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Journal articles on the topic 'Corneal lens'
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1
Mishra, S. K., G. S. Shrestha, P. Dhungel, and B. Aryal. "Visual outcome on Fitting Rose-K2 XL lens in a case with Terrien’s marginal degeneration." Journal of Chitwan Medical College 4, no. 4 (January 28, 2015): 49–51. http://dx.doi.org/10.3126/jcmc.v4i4.11974.
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Terrien’s marginal degeneration is an uncommon disease of the peripheral cornea occurring at any age that results in corneal thinning causing corneal irregular astigmatism. RoseK2 XL lens has an aspheric optical zone and employed in the fitting of irregular corneas for vision and comfort while maintaining corneal health. Rose K2 XL lens was fitted in a 17 year female presented to Contact lens clinic of B.P. Koirala Lions Center for Ophthalmic Studies, Kathmandu having RE Terrien’s marginal degeneration. Her presenting visual acuity was 6/60 in right eye and 6/6 in left eye with best subjective refraction OD: +2.00/-3.00X150 and OS: Plano. Her corneal topography revealed irregular corneal astigmatism as indicated by SimK49.85/41.63@137. RoseK2 XL which is a mini-scleral lens, showed an excellent fitting attaining visual acuity 6/6. RoseK2 XL lens provides not only good visual acuity also confirms comfort in patients with corneal marginal degeneration.DOI: http://dx.doi.org/10.3126/jcmc.v4i4.11974
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Shi, Rong, Weize Wang, Yu Che, Shaorong Linghu, and Taixiang Liu. "Effects of Corneal Stromal Lens Collagen Cross-Linking Regraft on Corneal Biomechanics." Journal of Ophthalmology 2022 (June 8, 2022): 1–7. http://dx.doi.org/10.1155/2022/8372156.
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Background. Corneal collagen cross-linking (CXL) therapy, a method that uses a combination of riboflavin and ultraviolet-A light (UVA), can promote the formation of covalent cross-linking of amino acid residues of corneal collagen and enhance the hardness of the cornea. In this study, we explored the effects of corneal stromal lens collagen cross-linking regraft on corneal biomechanics. Methods. A total of 15 New Zealand white rabbits were divided into 3 groups: normal control group (group A), SMILE + uncross-linked lens implantation group (Group B), and SMILE + cross-linking lens implantation group (group C). The design parameters of SMILE surgery were as follows: the corneal cap was 120 um thick, the lens diameter was 6.5 mm, and the diopter was -6.0D. Riboflavin and ultraviolet-A (UVA) were used as corneal stromal lens CXL, which was implanted into the allogeneic rabbit corneal stromal bag 24 hours after the operation. Postoperative corneal thickness (CCT), refraction, AS-OCT, and corneal biomechanics were performed before and then at 1 and 3 months after the operation. Results. All corneas appeared transparent and smooth 3 months after surgery. The corneal thicknesses of both group B and group C were lower than those before the operation. The corrected refraction of group B and group C after lens implantation was also lower than the expected corrected power; there was no significant difference between the two groups ( P > 0.05 ). AS-OCT results showed an uneven surface and thickness of the corneal stromal lens in two eyes of group B. Moreover, corneal elastic deformation increased with intraocular pressure in each group; displacement from large to small was group B > group C and > group A. The creep from large to small was group B > group C > group A. The fiberboard layers of groups B and C were disordered, and there were a few autophagosomes in the fibroblasts of group B by transmission electron microscopy (TEM). Conclusions. Allograft graft of corneal stromal lens collagen cross-linked can significantly increase the biomechanical properties of the cornea.
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Jester, J. V., T. Moller-Pedersen, J. Huang, C. M. Sax, W. T. Kays, H. D. Cavangh, W. M. Petroll, and J. Piatigorsky. "The cellular basis of corneal transparency: evidence for ‘corneal crystallins’." Journal of Cell Science 112, no. 5 (March 1, 1999): 613–22. http://dx.doi.org/10.1242/jcs.112.5.613.
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In vivo corneal light scattering measurements using a novel confocal microscope demonstrated greatly increased backscatter from corneal stromal fibrocytes (keratocytes) in opaque compared to transparent corneal tissue in both humans and rabbits. Additionally, two water-soluble proteins, transketolase (TKT) and aldehyde dehydrogenase class 1 (ALDH1), isolated from rabbit keratocytes showed unexpectedly abundant expression (approximately 30% of the soluble protein) in transparent corneas and markedly reduced levels in opaque scleral fibroblasts or keratocytes from hazy, freeze injured regions of the cornea. Together these data suggest that the relatively high expressions of TKT and ALDH1 contribute to corneal transparency in the rabbit at the cellular level, reminiscent of enzyme-crystallins in the lens. We also note that ALDH1 accumulates in the rabbit corneal epithelial cells, rather than ALDH3 as seen in other mammals, consistent with the taxon-specificity observed among lens enzyme-crystallins. Our results suggest that corneal cells, like lens cells, may preferentially express water-soluble proteins, often enzymes, for controlling their optical properties.
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Severinsky, Boris. "Silicone Hydrogel Miniscleral Contact Lenses after Corneal Collagen Crosslinking for Post-LASIK Keratoectasia." International Journal of Keratoconus and Ectatic Corneal Diseases 3, no. 3 (2014): 127–29. http://dx.doi.org/10.5005/jp-journals-10025-1092.
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ABSTRACT Purpose To report successful visual rehabilitation of post refractive surgery keratoectasia shortly after corneal collage crosslinking (CXL) procedure achieved with silicone hydrogel mini-scleral (SHmS) contact lens. Materials and methods A 29-year-old woman attended to our clinic with complaints on decreased vision in her left eye. Twelve years earlier she underwent bilateral laser-assisted in situ keratomileusis (LASIK) procedure for myopia correction. Corneal topography revealed bilateral central keratoectasia with maximal keratometry values of 55.4 Diopter (D) for her right eye and 59.7 D for the left, corneal thicknesses were 422 and 443 respectively. The patient underwent an uneventful CXL procedure in her left eye and was fitted with SHmS lens 5 weeks later. The lens was designed to rest over the patients’ sclera and perilimbal cornea and vault the central cornea with minimal support over it. Results SHmS lens fitting resulted in significant subjective improvement in visual acuity (from 20/200, unaided to 20/25, contact lens corrected). The patient was able to wear the lens upto 10 hours a day with stable contact lens corrected vision. No contact lens related complications, such as edema or neovascularization were observed during 3 months follow-up period. As a result of successful restoration of vision in the CXL-treated eye, the patient was scheduled for the procedure in her other eye. Conclusion SHmS contact lens should be considered as an option for the visual rehabilitation of corneas shortly after collagen corneal crosslinking procedure. This novel contact lens modality made from flexible and highly gas permeable material minimizes contact lens influence on corneal recovery after CXL and provides an excellent visual outcome. How to cite this article Severinsky B. Silicone Hydrogel Mini-scleral Contact Lenses after Corneal Collagen Crosslinking for Post-LASIK Keratoectasia. Int J Kerat Ect Cor Dis 2014;3(3):127-129.
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Rathor, Jogendra Kumar, Usman Memon, and Jignesh Jethva. "Effect of spherical rigid gas permeable lens on correction of corneal astigmatism." International Journal Of Community Medicine And Public Health 7, no. 12 (November 25, 2020): 4958. http://dx.doi.org/10.18203/2394-6040.ijcmph20205169.
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Background: Objectives were to study an effect of spherical RGP (rigid gas permeable) contact lens in correcting high corneal astigmatism more than 3 diopter.Methods: Total 48 eyes with corneal astigmatism greater than 3.00 diopter were included in study. At the first visit, routine preliminary examination, parameter assessment and subjective refraction has been carried out followed by patient counselling for RGP lens wear. Based on the corneal parameters considering keratometry as well as corneal topography, RGP lens trial was done. Post adaptation period, lens fitting analysis was done by understanding Fluorescein pattern with slit lamp and over refraction was done. Final lens has been ordered on this basis with understanding of tear lens formed, lens performance on cornea and edge width minimal of 0.80 mm to 1.00 mm. Patients were assessed at an interval of every two months from a date of lens dispensing.Results: The spherical RGP lens did correct the corneal astigmatism of more than 3D by formation of tear lens between cornea and lens. Vision improved by 2 to 3 lines compared to the spectacle correction without compromising corneal integrity at the central or peripheral cornea. Keratoconic eye showed significant vision improvement without the use of toric lens.Conclusions: Astigmatic eyes showed significant improvement in acuity with spherical RGP lens without compromising corneal integrity.
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Yang, Seung Ahn, Su Hwan Park, and Ji Eun Lee. "Clinical Use of Mini-Scleral Contact Lens in Ocular Surface Diseases." Annals of Optometry and Contact Lens 21, no. 3 (September 30, 2022): 99–103. http://dx.doi.org/10.52725/aocl.2022.21.3.99.
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A scleral contact lens lies on the sclera, not the cornea, which differs from a rigid gas permeable (RGP) contact lens, and has shown successful clinical outcomes in patients unable to tolerate glasses or RGP contact lenses because of a severely deformed cornea. In addition, a scleral lens forms a tear film between the cornea and contact lens that stabilizes the ocular surface and could be a useful therapeutic option. The mini-scleral contact lens is a useful therapeutic option for visual improvement and symptom control in patients with corneal abnormalities such as keratoconus, corneal opacity, ocular surface disease, and irregular corneal astigmatism.
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Spiteri, Natasha, Anshoo Choudhary, and Stephen Kaye. "Pigmentation of the Cornea Secondary to Tinted Soft Contact Lens Wear." Case Reports in Ophthalmological Medicine 2012 (2012): 1–2. http://dx.doi.org/10.1155/2012/852304.
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Purpose. To report a case of pigmented corneal iron lines following use of tinted soft contact lenses (CL).Methods. A retrospective case report.Results. A 16-year-old girl was referred with suspected CL-related keratopathy OU, having recently switched to tinted soft monthly disposable CLs (8.4/14.0 −3.00 OD, −3.25 OS Aquamarine SofLens Natural Colours, Bausch and Lomb, New York, USA). Both corneas exhibited symmetric superficial corneal pigmented iron lines, which gradually disappeared following discontinuation of CL wear.Conclusions. Pigmented corneal rings have been reported in normal ageing corneas, in certain pathological conditions, and in association with altered corneal topography following LASIK and orthokeratology. We suspect a poorly fitting CL resulted in localised tear pooling between the CL and cornea, and subsequent iron pigment deposition, similar to that seen with orthokeratology. Cosmetic CLs bought via the Internet can be used in an unsupervised manner, with possible impacts on visual function and potential complications.
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Willcox, M. D. P., and B. A. Holden. "Contact Lens Related Corneal Infections." Bioscience Reports 21, no. 4 (August 1, 2001): 445–61. http://dx.doi.org/10.1023/a:1017991709846.
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This article describes microbial keratitis, infection of the cornea by micro-organisms. Contact lens wear is a predisposing factor for the development of microbial keratitis. Micro-organisms probably adhere to the contact lens, transfer from the contact lens to a damaged or compromised corneal epithelial surface, penetrate into the deeper layers of the cornea and produce corneal damage. Host responses to the invading micro-organisms, while designed to protect the eye, can often exacerbate the situation and the resulting microbial keratitis can lead to permanent blindness. The microbial, biochemical and immunological aspects of MK will be described in detail.
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Grzybowski, Andrzej, and Piotr Kanclerz. "Tadeusz Krwawicz, MD: The inventor of cryosurgery in ophthalmology." European Journal of Ophthalmology 29, no. 3 (January 14, 2019): 348–56. http://dx.doi.org/10.1177/1120672118823125.
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Tadeusz Krwawicz (1910–1988) pioneered the use of cryosurgery in, as ophthalmology. The idea arose in 1959 while experimenting because on lyophilization to store corneas and lenses for transplantation it was difficult to remove the lens without damage the capsule was usually torn. Subsequent experiments on rabbits revealed that touching the lens with a wire cooled to 203°K (–70°C) resulted in firm attachment of the lens capsule and subcapsular masses. A cryoextractor was developed and employed for clinical use in cataract extraction, likewise in intumescent cataracts and lens subluxation. Cataract surgery utilizing cryoextraction led to substantial progress to ophthalmology by reducing the number of complications, particularly capsule rupture, and resulted in achieving better outcome compared to other methods. This surgery soon and for almost 20 years became a routine method used all around the world in cataract removal. Simultaneously, Krwawicz developed techniques for corneal refractive surgery—partial lamellar removal of the corneal stroma and temporary interlaminar introduction of a plastic disk in order to change the corneal curvature. Krwawicz presented other ophthalmic interests—his research concerned immunology, histology, histochemistry, biochemistry of ocular tissue, and mainly corneal and experimental surgery with a particular focus on the pathology of the cornea.
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Chukwuemeka, Obinwanne Junior, Damian C. Echendu, Isaura Ilorena D'Alva Brito dos Santos, Sharon Onwuka, and Osazee Agbonlahor. "REGIONAL VARIATION IN FLUID RESERVOIR THICKNESS, OXYGEN TRANSMISSIBILITY AND CORNEAL OEDEMA DURING SCLERAL LENS WEAR." Journal of Contact lens Research and Science 5, no. 1 (December 17, 2021): e32-e43. http://dx.doi.org/10.22374/jclrs.v5i1.48.
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Purpose: To determine if regional variation in post lens fluid reservoir thickness (PLFT) during scleral lens wear leads to regional variation in oxygen transmissibility and corneal edema during 4 hours of non-fenestrated scleral lens wear.Methods: About 20 healthy subjects (mean age, 28.8 ± 4.2 years) were fitted with nonfenestrated rotationally symmetric scleral lenses. Anterior segment optical coherence tomography was used to measure cornea thickness before and after lens wear, PLFT 10 minutes and 4 hours after lens application, and scleral lens thickness (with the scleral lens in situ) 4 hours after scleral lens application. These measurements were limited to the central 6 mm and divided into three zones (central, mid-peripheral, and peripheral zones). In the mid-peripheral and peripheral zones, eight principal meridians were measured, generating 17 measurement points in total. Scleral lens thickness and PLFT measurements were corrected for optical distortions by a series of equations. Oxygen transmissibility was calculated by dividing the scleral lens oxygen permeability by the optically-corrected scleral lens thickness, taking into account the oxygen permeability of saline and fluid reservoir thickness.Results: A significant regional variation in PLFT (F = 12.860, P = 0. 012) was observed after 10 minutes of the lens application, PLFT was thickest and thinnest in the inferotemporal and the superonasal region of the peripheral zones( 322.6 ± 161.8 µm and 153.8 ± 96.4 µm, respectively); however, this variation was not statistically significant at 4 hours of scleral lens wear (F = 4.692; P = 0.073). Despite significant regional variation in oxygen transmissibility (F = 48.472; P = 0.001) and relatively low oxygen transmissibility through the scleral lens, induced corneal edema did not vary significantly in different regions (F = 3.346; P = 0.126). In the central corneal region, the induced corneal edema correlated moderately with PLFT (r = 0.468; P = 0.037) and oxygen transmissibility (r = -0.528; P = 0.017). This relationship was insignificant in the peripheral cornea.Conclusion: The inferotemporal peripheral region had the thickest PLFT and least oxygen transmissibility, and the superonasal region had the vice versa. Despite significant variation in PLFT and oxygen transmissibility initially, in healthy corneas, this variation does not seem to induce statistically significant regional variation in corneal edema. Increased central PLFT and decreased oxygen transmissibility moderately correlate with central corneal edema.
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Obraztsova, M. R., I. A. Mushkova, and N. V. Maychuk. "Application of the method of accelerated ultraviolet crosslinking of corneal collagen using a customized protective contact lens without an ultraviolet filter in a patient with secondary keratoectasia after Lasik (a clinical case)." Modern technologies in ophtalmology, no. 2 (June 15, 2021): 71–74. http://dx.doi.org/10.25276/2312-4911-2021-2-71-74.
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Purpose. To evaluate the clinical and functional results of the technique of ultraviolet crosslinking on the thin cornea using a customized soft contact lens without an ultraviolet filter in a patient with secondary corneal ectasia. Material and methods. Under observation was patient S., 32 years old, diagnosed with secondary keratoectasia of the left eye after LASIK surgery, performed in 2008 for moderate myopia. To stabilize the keratectatic process, complicated by the presence of a thin cornea with a thickness of less than 400 microns, an operation was performed: ultraviolet crosslinking of corneal collagen using a customized protective lens without an ultraviolet filter. Results. There were no complications during and after the operation. According to keratorefractometry and keratotopography, there was no progression of the disease after surgery, and no loss of endothelial cells was detected. Conclusion. Thus, conducting ultraviolet crosslinking of corneal collagen using a protective customized lens without an ultraviolet filter is a promising technique that allows you to achieve stabilization of the keratectatic process. Key words: corneal ectasia, thin cornea, UV crosslinking, customized lens.
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Pyltsina, N. Yu, E. A. Bezbabnova, A. A. Selezneva, and M. S. Shmelkova. "A Clinical Case of Fitting Scleral Lens for Correction of Pellucid Marginal Degeneration." EYE GLAZ 23, no. 4 (December 12, 2021): 17–20. http://dx.doi.org/10.33791/2222-4408-2021-4-17-20.
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Background. Pellucid Marginal Degeneration (PMD) is a rare bilateral degenerative corneal disease. It causes corneal ectasia with bilateral, clear, inferior (typically 4 o’clock to 8 o’clock), peripheral corneal thinning. It usually affects about 80% of corneal stroma, which leads to the corneal ectasia above the thinning area as well as provokes the irregular astigmatism and visual impairment that are difficult to correct. Purpose. To study the possibilities of correction and social rehabilitation in a patient with PMD wearing scleral lenses. Materials and methods. The study included a patient with PMD, signs of corneal dysfunction and narrow-angle subcompensated glaucoma in the right eye, and PMD of the cornea resulted in a corneal leukoma – terminal glaucoma in the left eye. In addition to standard ophthalmic methods, we performed corneal topography and optical coherence tomography (OCT). For intraocular pressure measurement, ICARE IOP tonometer was used in several areas of the intact peripheral cornea. Results. Prior to lens fitting, UCVA in the right eye amounted to 0.06. Scleral lens helped achieve a high visual acuity of 0.9–1.0. The lens was well-tolerated by the patient. Conclusion. Scleral lenses may be a good choice for patients with irregular cornea caused by corneal dystrophy. Not only they are easy to use and have a good visual effect, but they also help patients with social rehabilitation.
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Erdinest, Nir, Ortal Palatchi Sabag, Naomi London, and Abraham Solomon. "Quadrant Asymmetric Design Contact Lens for Visual Rehabilitation after Eye Trauma." Case Reports in Ophthalmology 12, no. 2 (May 6, 2021): 330–36. http://dx.doi.org/10.1159/000512505.
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The purpose of this case report is to demonstrate the efficacy of an asymmetric peripheral design scleral contact lens in a case of highly irregular corneal-scleral pattern due to trauma. A 63-year-old patient was involved in a jeep accident which caused a partial-thickness penetrating injury to the peripheral cornea of his left eye. The subsequent corneal irregularity extended beyond the limbus into the sclera which made it difficult to stabilize a contact lens. A quadrant specific peripheral curve (quadrant asymmetric periphery) scleral contact lens successfully resulted in improved comfort and visual acuity. This is the first known published case to use this lens design to correct a post-trauma irregular cornea-scleral relationship. Quadrant asymmetric periphery scleral contact lenses can be effective in cases of severe irregular corneal-scleral patterns.
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Steiber, Zita, András Berta, and László Módis. "Contact lens-related keratitis." Orvosi Hetilap 154, no. 45 (November 2013): 1781–89. http://dx.doi.org/10.1556/oh.2013.29717.
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Nowadays, keratitis, corneal infection due to wearing contact lens means an increasingly serious problem. Neglected cases may lead to corneal damage that can cause blindness in cases of otherwise healthy eyes. Early diagnosis based on the clinical picture and the typical patient history is an important way of prevention. Prophylaxis is substantial to avoid bacterial and viral infection that is highly essential in this group of diseases. Teaching contact lens wearers the proper contact lens care, storage, sterility, and hygiene regulations is of great importance. In case of corneal inflammation early accurate diagnosis supported by microbiological culture from contact lenses, storage boxes or cornea is very useful. Thereafter, targeted drug therapy or in therapy-resistant cases surgical treatment may even be necessary in order to sustain suitable visual acuity. Orv. Hetil., 154(45), 1781–1789.
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Lundanes, Eilin, and Jörgen Gustafsson. "Refitting a patient with pellucid marginal degeneration from a corneal rigid gas permeable lens to scleral lens." Scandinavian Journal of Optometry and Visual Science 13, no. 1 (July 31, 2020): 19–23. http://dx.doi.org/10.5384/sjovs.vol13i1p19-23.
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This case report describes a 66 years old male patient with pellucid marginal degeneration (PMD). The patient had fallen out of a regular follow-up scheme and presented with a poorly fitting corneal rigid lens that he had worn for almost five years. Correction had failed to improve vision in the left eye, so the patient wears a contact lens in his right eye only. Scleral lenses vault over the cornea, the tear layer between the lens and the cornea masks corneal irregularities and are a good correction option for corneal ectasias. This patient was fitted with an Onefit scleral lens that provided good visual acuity and comfort. Lens handling was no obstacle to this patient. A heart surgery postponed the first follow-up examination. Follow-up examination 8 months after the refit resulted in no changes of lens parameters as the fitting was still acceptable and the patient was happy. Attention to the inferior limbal clearance will be the focus at the next follow-up in 6 months’ time.
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Farid, Marjan. "Pearls for Secondary Intraocular Lens Implantation." US Ophthalmic Review 10, no. 01 (2017): 13. http://dx.doi.org/10.17925/usor.2017.10.01.13.
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Marjan Farid is Director of the Cornea, Cataract, and Refractive Surgery Faculty and Vice-chair of the Ophthalmic Faculty at the Gavin Herbert Eye Institute (GHEI) at the University of California, Irvine (UCI), California, US. Dr Farid’s clinical practice is divided between patient care, teaching, and research. She enjoys teaching ophthalmology to medical students, ophthalmology residents, and cornea fellows. She serves on the Residency Education Committee and is the Director of the cornea fellowship program at the GHEI. Her research interests focus on corneal surgery, specifically in the use of the femtosecond laser for corneal transplantation. She performs all forms of corneal transplantation—femtosecond enabled and lamellar keratoplasty (DSEK and DALK). Dr Farid is also the founder of the severe ocular surface disease center at UCI. She performs limbal stem cell transplants, as well as artificial corneal transplantation for the treatment of patients with severe ocular surface disorders. She serves as an associate medical director for the Sight Life Eye Bank. Her work has been published in numerous peer-reviewed journals, she has authored six textbook chapters, and travels to multiple national meetings to present her research work. She serves as an Editorial Board member of Ophthalmology, the leading journal in her field. Dr Farid graduated summa cum laude from UCLA with a degree in biology. She earned her medical degree at UC-San Diego in 2002 and completed a transitional year internship at Scripps-Mercy Hospital in San Diego. She completed her residency training in ophthalmology at UCI. She subsequently completed her fellowship training in the area of cornea/external disease and refractive surgery under the mentorship of Dr Roger Steinert at UCI.
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Park, Young Kee. "How to Improve Success Rate of Rigid Gas Permeable Lens Prescription." Annals of Optometry and Contact Lens 20, no. 3 (September 25, 2021): 94–98. http://dx.doi.org/10.52725/aocl.2021.20.3.94.
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A rigid gas permeable (RGP) lens is good for correcting corneal astigmatism without inducing corneal hypoxia. However, despite the optical advantage of the RGP lens for correcting visual acuity, there may be circumstances in which a patient may choose not to wear the RGP lens. For example, because the RGP lens is smaller than the cornea, it may cause a foreign body sensation due to lens movement and blurring, especially at night. Thus, the success of the RPG lens prescription depends on the selection of the proper candidates and lenses, with appropriate fitting and follow-up management by a doctor.
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Terzariol, Mariana, Paula S. Hünning, Gustavo Brambatti, Luciane de Albuquerque, Carolina Neumann, and João A. T. Pigatto. "Effects of intracameral brilliant blue on the corneal endothelium of swine: in vitro study." Pesquisa Veterinária Brasileira 36, no. 8 (August 2016): 775–80. http://dx.doi.org/10.1590/s0100-736x2016000800016.
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Abstract: The aim was to investigate the ultrastructural changes in the corneal endothelium of pigs induced by intracameral 0.05% brilliant blue. Twenty swine corneas were separated into two groups, the right eye bulbs (control group) and the left eye bulbs (experimental group) of the same animal. All the eye bulbs were evaluated with specular microscopy. The cornea of the right eye bulbs was excised and in the left eye bulbs 0.2ml of 0.05% brilliant blue vital dye (OPTH-blue±) was injected into the anterior chamber, where it remained for one minute. Then the anterior chamber was cleaned with a balanced salt solution injection and the cornea was excised too. All the corneas were evaluated by scanning electron microscopy to evaluate the changes on the endothelium caused by the brilliant blue dye. There were no significant differences between the right corneal endothelium cells and the left corneal endothelium cells with scanning electron microscopy after intracameral use of 0.05% brilliant blue dye. The 0.05% brilliant blue dye concentration did not cause deleterious effects for the swine corneal endothelium after intracameral use and can be a choice for safe staining of the anterior capsule of the lens in cataract surgery.
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Reneker, L. W., D. W. Silversides, L. Xu, and P. A. Overbeek. "Formation of corneal endothelium is essential for anterior segment development - a transgenic mouse model of anterior segment dysgenesis." Development 127, no. 3 (February 1, 2000): 533–42. http://dx.doi.org/10.1242/dev.127.3.533.
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The anterior segment of the vertebrate eye is constructed by proper spatial development of cells derived from the surface ectoderm, which become corneal epithelium and lens, neuroectoderm (posterior iris and ciliary body) and cranial neural crest (corneal stroma, corneal endothelium and anterior iris). Although coordinated interactions between these different cell types are presumed to be essential for proper spatial positioning and differentiation, the requisite intercellular signals remain undefined. We have generated transgenic mice that express either transforming growth factor (alpha) (TGF(alpha)) or epidermal growth factor (EGF) in the ocular lens using the mouse (alpha)A-crystallin promoter. Expression of either growth factor alters the normal developmental fate of the innermost corneal mesenchymal cells so that these cells often fail to differentiate into corneal endothelial cells. Both sets of transgenic mice subsequently manifest multiple anterior segment defects, including attachment of the iris and lens to the cornea, a reduction in the thickness of the corneal epithelium, corneal opacity, and modest disorganization in the corneal stroma. Our data suggest that formation of a corneal endothelium during early ocular morphogenesis is required to prevent attachment of the lens and iris to the corneal stroma, therefore permitting the normal formation of the anterior segment.
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Kummelil, Mathew Kurian, Rohit Shetty, Luci Kaweri, Shama Shaligram, and Mukesh Paryani. "Outcomes of a Management Strategy in Eyes with Corneal Irregularity and Cataract." BioMed Research International 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/8497858.
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Purpose. To evaluate the outcomes of a management strategy in patients with irregular corneas and cataract.Methods. Six eyes of four patients presented for cataract surgery with irregular corneas following corneal refractive surgery. Topoguided ablation regularised the cornea, followed by phacoemulsification and intraocular lens implantation. Zonal keratometric coefficient of variation (ZKCV) measured structural changes and visual quality metrics measured functional improvement.Results. The mean duration after corneal refractive surgery was7.83±2.40years. The logmar uncorrected distance visual acuity (0.67±0.25) and the corrected distance visual acuity (0.38±0.20) improved to0.34±0.14and0.18±0.10, respectively. The changes in the standard deviations of the zonal keratometry values and the ZKCV were statistically significant in the 2, 3, and 4 mm zones. The changes in the Strehl ratio (ANOVAp=0.043) were also statistically significant.Conclusions. Corneal regularisation followed by phacoemulsification resulted in lower residual refractive error with improved visual quality metrics. This strategy is a viable option in patients with symptomatic cataracts and irregular corneas.
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JEONG, Se-Kwon. "From contact lens to ‘Dream Lens’ - Cultural History of Vision Correction Technology." Korean Journal of Medical History 32, no. 1 (April 30, 2023): 81–111. http://dx.doi.org/10.13081/kjmh.2023.32.81.
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This paper traces how medical technologies to correct vision were introduced and changed in Korean society until the introduction of Orthokeratology called ‘Dream Lens’ in the late 1990s. First of all, I outlines the historical background of the introduction and spread of the relatively unfamiliar and expensive Orthokeratology, which is said to “cure” myopia and astigmatism by pressing the cornea. ‘Dream Lens’, a ‘lens for correcting corneal refractive error’, was a popular vision correction technology in terms of its name, treatment method, and effect. Not only was it introduced with a name similar to contact lens used instead of glasses from decades ago, but the way it was attached to and removed from the cornea was also similar. On the other hand, the public was already familiar with the principle of correcting the refractive index by pressing the cornea and improving visual acuity in the long term, just like LASIK which became popular in the mid-1990s. The use of contact lens which was similar in terms of the name ‘lens’ and the effect of ‘correcting vision’, and the trend of LASIK which was similar in principle of controlling corneal refraction, was a historical stage that helped soft landing of orthokeratology.However, from contact lens, vision correction technology did not settle down without any conflict. There was a conflict between medical experts traditionally responsible for optometry and production of spectacles and lens, and opticians who were newly in charge of that area. Ophthalmologists who have been in charge of optometry and prescriptions for a long time had no choice but to hand over some of the inspection areas to opticians due to the rapidly increasing number of opticians and the implementation of the optician system in 1989. And they had no choice but to watch the expansion of the business of opticians who manufactured glasses based on their own vision tests and sold them together with contact lens. Instead, corneal resection, which is not a technique for correcting visual acuity due to corneal refractive error, but a surgical technique for treating the corneal refractive error itself, has become an ophthalmologist's unique task. In addition, Dream Lens, which corrects corneal refractive error using a similar principle, has also become an object of professional medical practice because it required more precise examination and treatment than eyeglasses or contact lenses. By understanding the process by which vision correction technologies, from contact lens to dream lens, have been introduced into Korean society over the past few decades, this paper gives a new understanding how different medical technologies with the same or similar purposes are settling down, and the tension between experts in charge of them.
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Nadeem, Sana. "Tree Sap Induced Corneal and Lens Crystals." Pakistan Journal of Ophthalmology 35, no. 4 (January 23, 2020): 298–301. http://dx.doi.org/10.36351/pjo.v35i4.885.
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This is a peculiar case of localized, silvery, iridescent crystal deposition in the cornea and lens, discovered twenty seven years after injury with an overhanging tree branch with sap exposure. The corneal tear at the time of injury was self sealing and there was also associated lens trauma, both managed conservatively on an inpatient basis, and leading subsequently to a corneal scar and localized cortical cataract, respectively, both demonstrating fine, silver, interspersed crystals. This is the first case to be reported in the world, of corneal crystal deposition in conjunction with lenticular crystals as a result of a tree branch injury.
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Ivachev, E. A., E. V. Anisimova, and I. P. Denisova. "Results of Cataract Extraction in Patients with Corneal Opacity." Ophthalmology in Russia 16, no. 2 (June 30, 2019): 179–84. http://dx.doi.org/10.18008/1816-5095-2019-2-179-184.
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Purpose. To evaluate the effectiveness of cataract extraction in patients with varying degrees of corneal opacity.Patients and methods. We performed cataract extraction with implantation of the intraocular lenses of 14 eyes (9 patients) with varying degree of corneal opacity. The causes of corneal opacities were: keratitis in anamnesis — 6 cases, the result of wearing soft contact lenses — 2 eyes, eye injury — 2, the outcome of dermatitis of unspecified genesis with eye damage — 3, perforation of the corneal ulcer — 1 case. In 9 eyes, opacity of the cornea occupied the optic part of the cornea, in 5 cases, the opacity of the cornea was in the paraoptic zone. The middle uncorrected visual acuity of all cases is 0.05 ± 0.03, and the middle best corrected visual acuity is 0.14 ± 0.07. The phacoemulsification of the cataract with implantation of the intraocular lens was performed for all the patients.Results. There were no complications during the operation, in the early and late postoperative periods. As a result of cataract extraction, all patients, regardless of the degree of cornea opacity, noted vision improvement. On the first day after the operation, the middle best corrected visual acuity was 0.06 ± 0.02 in 4 eyes, in 10 cases the middle best corrected visual acuity was 0.09 ± 0.03. The middle best corrected visual acuity 7 days after the surgery was 0.31 ± 0.07. After 6 months of observation of patients with corneal opacity after phacoemulsification of the cataract with implantation of the intraocular lens, the most corrected visual acuity was 0.27 ± 0.19.Conclusions. All patients with corneal opacity of varying degrees of intensity after cataract extraction noted improved vision. The central location of the opacity of the cornea significantly reduced visual acuity, and paraoptic — influenced the vision to a lesser extent. The degree of cornea turbidity was also affected the initial visual acuity — the more clouding and the depth of the cornea, the lower the vision. The result of the lens extraction also depended on the maturity of the cataract — with a more turbid lens the result was higher in relation to preoperative indices.
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Barodawala, Fakhruddin. "RESHAPING TORIC CORNEAS WITH ORTHOKERATOLOGY." Journal of Contact lens Research and Science 6, no. 1 (March 14, 2022): e1-e8. http://dx.doi.org/10.22374/jclrs.v6i1.49.
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The use of specially designed reverse geometry lenses, known as orthokeratology (ortho-K) lenses, has gained popularity recently. There are various names to this technique: corneal reshaping therapy, corneal refractive therapy, overnight corneal reshaping, corneal molding system, Vision Shaping Treatment, and many more. The advantage of applying this technique is that it results in a temporary reduction of the refractive error by flattening the central cornea with overnight wear of the specially designed lens. Ortho-K lenses are also widely used as a modality for slowing myopia progression in children. With advances in technology and lens design, high refractive errors and astigmatism are now possible to correct. This case presentation summarizes a successful fitting of toric ortho-K lenses to reshape a toric cornea with highmyopia and astigmatism.
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Mishra, Sanjeeb Kumar, Meenu Chaudhary, Niraj Dev Joshi, Ayush Chandan, and Pragati Gautam. "Visual outcome of fitting Rose-K2 XL lens in a case with advanced keratoconus." Journal of Physiological Society of Nepal 3, no. 1 (June 30, 2022): 27–30. http://dx.doi.org/10.3126/jpsn.v3i1.57766.
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Keratoconus is a progressive non inflammatory bilateral but usually asymmetric corneal disease characterised by paraxial stromal thinning and weakening that leads to corneal surface distortion. Rose K2 XL lens has an aspherical optical zone and employed in the fitting of irregular corneas for vision and comfort while maintaining corneal health. Rose K2 XL lens was fitted in a 35 year old male presented to contact lens clinic of BP Koirala Lions Centre for Ophthalmic Studies, Kathmandu having advanced keratoconus. His presenting best corrected visual acuity was 6/36 in right eye with plano and 2/60 in left eye with plano with no improvement with glasses.The corneal topography performed with Bon Sirius showed keratoconus compatible in both eyes. Rose K2 XL is a mini scleral lens which saw excellent fitting attending visual acuity of 6/12 in both eye. Rose K2 XL lenses are of viable alternative in the visual rehabilitation of patients with advanced keratoconus.
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Matsuzaki, Yusuke, Hiroshi Toshida, Toshihiko Ohta, and Akira Murakami. "A Case of Atypical Mucin Balls Wearing Extended Wear of Silicone Hydrogel Lens for Therapeutic Use." Case Reports in Ophthalmological Medicine 2013 (2013): 1–3. http://dx.doi.org/10.1155/2013/167854.
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A 25-year-old man visited our hospital showing atopic conjunctivitis and corneal shield ulcer on his left eye. Although eye drops of 0.1% of betamethasone sodium phosphate and 0.1% of hyaluronic acid ophthalmic solution were prescribed, calcific corneal opacities developed. The corrected visual acuity decreased to 6/20 in Snellen chart. After corneal epithelial exfoliation, removal of calcific corneal opacity was scrubbed with MQA soaked in 0.05 M of ethylenediaminetetraacetic acid (EDTA). After washing the eye with 200 mL of physiological saline, a silicon hydrogel lens, PureVision (balafilcon A), was inserted to obtain pain relief for the therapeutic use. At postoperative day 11, mucin balls were found between cornea and contact lens and stained by rose bengal dye. One of them was atypically larger than usual, and the major axis was approximately 1.5 mm. Wearing lens was stopped, and all of mucin balls and corneal staining were disappeared at postoperative day. Little corneal opacity remained, and visual acuity after surgery recovered to 14/20 at five months.
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Teo, Alvin Wei Jun, Jingwen Zhang, Lei Zhou, and Yu-Chi Liu. "Metabolomics in Corneal Diseases: A Narrative Review from Clinical Aspects." Metabolites 13, no. 3 (March 3, 2023): 380. http://dx.doi.org/10.3390/metabo13030380.
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Corneal pathologies may have subtle manifestations in the initial stages, delaying diagnosis and timely treatment. This can lead to irreversible visual loss. Metabolomics is a rapidly developing field that allows the study of metabolites in a system, providing a complementary tool in the early diagnosis and management of corneal diseases. Early identification of biomarkers is key to prevent disease progression. The advancement of nuclear magnetic resonance and mass spectrometry allows the identification of new biomarkers in the analysis of tear, cornea, and aqueous humor. Novel perspectives on disease mechanisms are identified, which provide vital information for potential targeted therapies in the future. Current treatments are analyzed at a molecular level to offer further information regarding their efficacy. In this article, we provide a comprehensive review of the metabolomic studies undertaken in the cornea and various pathologies such as dry eye disease, Sjogren’s syndrome, keratoconus, post-refractive surgery, contact lens wearers, and diabetic corneas. Lastly, we discuss the exciting future that metabolomics plays in cornea research.
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Yingmei, Jiang, Jin Tao, Yang Xueqi, Dai Xiaoli, Jin Ri, Xu Huancai, and Wang Xiuying. "An Analysis on the Change Rule of Eyeball's Biological Parameters of Different Types in the Refraction State and Vision Before and After Refraction." Journal of Medical Imaging and Health Informatics 8, no. 9 (December 1, 2018): 1881–85. http://dx.doi.org/10.1166/jmihi.2018.2532.
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The ametropia is the most widespread eye disease for the humans. Wherein, the myopia is the commonest ophthalmological reason influencing the distant vision. The excimer laser corneal refractive surgery has always been an operation mode most widely used in myopic correction operations for a number of years. The laser assisted in-situ keratomi (LASIK) mainly transforms the frontal surface appearance of the cornea to change the corneal refraction power, and its correction effect is influenced by a great many factors such as regression and hydration of cornea. Thus, a lot of surgeons would combine own experience in conducting LASIK myopic correction. The myopic regression would affect the foreseeability, operation effect and stability of corneal refractive surgery, which results in reduction of the patients' visual quality in turn. The pathogenesis still needs further study. The change of lens thickness does not only lead to change in depth of central anterior chamber, but also would cause the change in refractive power of lens, thereby influencing the whole dioptric system of the eyeball. The previous research on postoperative regression was mostly focused on the corneal refraction, while few efforts were put in the changes of lens thickness and refractive power after LASIK.
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Goldberg, Joe B. "Corneal lens flexure." International Contact Lens Clinic 17, no. 9-10 (September 1990): 249. http://dx.doi.org/10.1016/0892-8967(90)90065-n.
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Kawahara, Atsushi, Tatsuhiko Sato, and Ken Hayashi. "Multivariate Regression Analysis to Predict Postoperative Refractive Astigmatism in Cataract Surgery." Journal of Ophthalmology 2020 (January 14, 2020): 1–7. http://dx.doi.org/10.1155/2020/9842803.
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Purpose. To assess the correlation between postoperative refractive astigmatism and preoperative parameters in cataract surgery. Methods. Left eyes of 100 consecutive patients scheduled for cataract surgery with a 2.4 mm clear corneal incision were examined prospectively. Refractive astigmatism was measured using an autokerato/refractometer. Corneal astigmatism of the total cornea was calculated using a Scheimpflug camera. The vertical/horizontal component (J0) and oblique component (J45) of refractive and total corneal astigmatism were determined using power vector analysis. Refractive astigmatism at 8 weeks postoperatively was estimated using multivariate linear regression analysis. Independent variables analyzed included age, sex, refractive astigmatism, total corneal astigmatism, sphere, intraocular pressure, corneal thickness, anterior chamber depth, lens thickness, axial length, and pupil diameter. Results. Multivariate regression analysis identified total corneal J0 and age as significant contributors to postoperative refractive J0 (P<0.001 and P=0.029, respectively). The standard partial regression coefficients in the multiple regression analysis were 0.59 and −0.16 for total corneal J0 and age, respectively. Significant contributors to postoperative refractive J45 were total corneal J45 and lens thickness (P<0.001 and P=0.015, respectively). The standard partial regression coefficients were 0.79 and −0.15 for total corneal J45 and lens thickness, respectively. Conclusion. These results suggest that preoperative total corneal astigmatism is the most significant predictor of postoperative refractive astigmatism when performing astigmatism correction in cataract surgery.
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Tereshchenko, A. V., I. G. Trifanenkova, Yu Y. Golubeva, S. K. Demianchenko, and E. N. Vishnyakova. "Ultraviolet crosslinking of corneal collagen in patients with thin cornea. Literature review." Acta Biomedica Scientifica 6, no. 6-1 (December 28, 2021): 229–36. http://dx.doi.org/10.29413/abs.2021-6.6-1.26.
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For the treatment of progressive keratoconus in the early stages, corneal collagen crosslinking is currently actively used. This technique is based on the stabilization of the pathological process by increasing the biomechanical properties of the own cornea. The thickness of the cornea less than 400 microns significantly limits the possibility of a standard cross-linking procedure performing.The article analyzes the literature data on the use of various methods of corneal crosslinking with a corneal thickness of less than 400 microns, which signifi cantly limits the possibilities of the standard procedure.It is known, that during crosslinking, at the initial stage, de-epithelialization of the cornea is performed, which, in the postoperative period, leads to a pronounced corneal syndrome. This determined the direction of the fi rst modifi cations of the technique associated with the use of partial de-epithelialization or its complete absence. Later, during cross-linking of “thin” corneas, techniques with the use of additional covering materials were actively used in order to replenish the missing corneal tissue of the patient during the UV irradiation procedure. Among them are the use of a soft contact lens without an ultraviolet fi lter, the use of a corneal lenticule obtained after SMILE surgery, the use of a protective fl ap of the donor cornea obtained using a femtosecond laser from the residual stroma of the corneal disc after descemet membrane transplantation or posterior lamellar keratoplasty. The variety of the proposed modifications and the ongoing search for better options indicate the demand for this technology and the need for further research, taking into account the individual characteristics of the patient’s ectasia.
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Ono, Takashi, Yosai Mori, Ryohei Nejima, Takuya Iwasaki, Shiro Amano, and Kazunori Miyata. "Optical Coherence Tomography Examination of the Anterior Segment in a Case of Corneal Perforation and Lens Trauma by Chestnut Burr." Case Reports in Ophthalmology 9, no. 1 (February 14, 2018): 160–65. http://dx.doi.org/10.1159/000487076.
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Chestnut burrs, the thorny encapsulation of chestnut fruit, can sometimes cause corneal injuries and ulceration, with poor prognoses. We report a case of corneal perforation and damaged anterior lens capsule due to a chestnut burr, using anterior segment optical coherence tomography (AS-OCT). A 67-year-old woman with a chestnut burr injury in her right eye was referred to our hospital. Her right best-corrected visual acuity (BCVA) was 0.8. Slit-lamp examination and AS-OCT showed perforation involving the endothelial layer at the center of the cornea. The iris and anterior lens capsule were damaged. Cell infiltration was observed around the wound. Bacterial examination showed gram-positive cocci but no fungi. The patient was diagnosed with a corneal perforation and bacterial keratitis. Levofloxacin 1.5% and cefmenoxime treatments were initiated and a soft contact lens was placed to seal the wound. On day 3, there was no improvement in the corneal cell infiltration, but AS-OCT suggested that the inner wound had closed. A culture test revealed the presence of Propionibacterium acnes, which was sensitive to both levofloxacin and cefmenoxime. Therefore, we continued the same antibiotic treatment. On day 26, the opacification and cell infiltration at the center of the cornea had improved. AS-OCT showed healing of the corneal wound with reduction in the central corneal thickness. Her BCVA improved to 1.0. AS-OCT was a valuable tool to noninvasively observe wound shape and detect the presence of any intracorneal foreign bodies.
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Maxam, Annika. "Kontaktoptische Rehabilitation eines Auges mittels Sklerallinse nach einer Schwefelsäureverletzung." Optometry & Contact Lenses 1, no. 3 (September 29, 2021): 105–10. http://dx.doi.org/10.54352/dozv.bydp2245.
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Purpose. The case report describes the optical rehabilitation of one eye by scleral lens fitting after a sulfuric acid related occupational accident. Material and Methods. Based on the corneal topography determined by Pentacam and other slit-lamp examinations relevant for contact lens fitting, a custom-made scleral lens was fitted on the basis of diagnostic contact lenses. The fit assessment of the diagnostic contact lens was performed by interpreting the fluorescein image as well as the centration behavior of the lens. Results. With the help of the fitted scleral lens a sufficient visual acuity of 20/25 in the right eye with a stereopsis in connection with a good subjective and objective acceptance could be achieved. This was associated with a professional reintegration. Conclusion. In many cases of complex ocular injuries, con- tact lens fitting with scleral lenses is the means of choice for optical rehabilitation of the affected eye. The fitting of scleral lenses requires an experienced practitioner both in the evaluation of the issues relevant for the contact lens design and in the evaluation of the anterior segment of the eye and here in particular the cornea. Keywords acid burn, corneal erosion, irregular cornea, mini scleral lens, scleral lens, sulfuric acid
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Hakim, Affannul, and Christina Aritonang. "Good Outcome of Corneal Ulcer With Hypopion After Long Use of Contact Lens." Vision Science and Eye Health Journal 2, no. 3 (July 31, 2023): 74–79. http://dx.doi.org/10.20473/vsehj.v2i3.2023.74-79.
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Introduction: Microbial keratitis is a corneal infection caused by microorganisms and is characterized by a profound corneal epithelial defect that infects the cornea and causes severe and progressive visual loss. In recent years, the incidence of microbial keratitis has increased. One of the critical risk factors for increasing this incidence is using contact lenses. As the number of contact lens users increases, the number of corneal ulcers associated with contact lenses also increases. Case Presentation: A 25-year-old man was admitted to the emergency department with a complaint of gradually blurry vision in his left eye four days after using contact lenses for overnight uses since the previous few days and did not routinely clean contact lenses or replace contact lens cleaning fluid. The visual acuity of the patient's left eye was hand movement with conjunctival and pericorneal injection in the conjunctiva and 6 x 7 mm stromal level infiltrate, blurred margin, and whitish color in the center of the cornea. After 28 days of treatment, an examination showed the patient's left eye improvement. Visual acuity was 3/60, conjunctival injection disappeared, corneal swelling significantly resolved, hypopyon disappeared, and ulcer completely re-epithelialized. Conclusions: Empirical therapy with broad-spectrum antibiotics and other adjunctive therapy has a good outcome in treating contact lens-related corneal ulcers.
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Parthasarathi, Priyadarshini, Venipriya, Justin Prashanth, and Hannah Ranjee Prasanth. "Atypical presentation of macular corneal dystrophy." Indian Journal of Clinical and Experimental Ophthalmology 8, no. 3 (October 15, 2022): 428–30. http://dx.doi.org/10.18231/j.ijceo.2022.086.
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A 65-year old male patient presented to our ophthalmology OPD for regular check up. On examination visual acuity of the right eye was 6/24 improving to 6/12p with pinhole and left eye was 6/18 improving with pinhole 6/9. On examination of anterior segment both eyes cornea showed multiple white round deposits at deep posterior stroma and Descemet membrane – endothelium complex scattered circumferentially in the peripheral cornea and the central cornea clear and lens showed Immature cataract. Fundus examination was within normal limits. A differential diagnosis of stromal corneal dystrophy or endothelial corneal dystrophy was made. By exclusion, we came to the diagnosis of macular corneal dystrophy.
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Ruan, Xiaoting, Zhenzhen Liu, Lixia Luo, and Yizhi Liu. "The Structure of the Lens and Its Associations with the Visual Quality." BMJ Open Ophthalmology 5, no. 1 (September 2020): e000459. http://dx.doi.org/10.1136/bmjophth-2020-000459.
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In humans, the lens is the organ with the ability to change morphology and refractive power, designated as accommodation, to focus light from various distances and obtain clear retinal image. The accommodative ability of the lens depends on its structure and biological parameters. The lens grows throughout the life, forming specific lens sutures and a unique gradient refractive index, and possesses regenerative ability under certain circumstances. Minimally invasive lens surgery that preserves endogenous lens epithelial stem/progenitor cells (LECs) can achieve functional lens regeneration in humans. The lens is the main source of intraocular aberration, especially intraocular higher-order aberrations (IHOAs) which is found to be binocularly symmetrical in phakic eyes. There is a compensation mechanism between corneal aberrations and lens aberrations. Therefore, the structure and the biological parameters of the lens, the binocular relationship of the lens and the correlation between the lens and cornea affect visual quality. This paper summarises the above findings and their current and potential applications in refractive surgeries, providing a comprehensive understanding of the lens as a strong determinant of visual quality in the optical system.
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Cherny, Christina, Suzanne Sherman, and Danielle Trief. "CONTACT LENS MODIFICATIONS FOR BOSTON KERATOPROSTHESIS." Journal of Contact lens Research and Science 6, no. 1 (November 3, 2022): e9-e17. http://dx.doi.org/10.22374/jclrs.v6i1.50.
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Boston Keratoprosthesis Type 1 (KPro), an artificial cornea, is a therapeutic option for patients in need of corneal transplantation when the prognosis of traditional keratoplasty is guarded. Bandage contact lens wear is essential in the post-operative management of KPro eyes in order to maintain adequate corneal graft hydration, and minimize the risk of adverse complications. Suitable bandage contact lens selection is imperative to preserve keratoprosthesis function, and customized modifications of contact lens parameters may be necessary to ensure adequate fitting. The available contact lens options, modifications, and protocols for the continued care of Boston Keratoprosthesis are discussed. A simple, yet unreported modification for contact lenses fit over KPro eyes in the setting of ocular surface irregularities is proposed, which may hold clinical utility when fitting keratoprosthesis patients with scleral elevations and glaucoma filtrationdevices.
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Rhem, Marcus N., Elizabeth M. Lech, Joseph M. Patti, Damien McDevitt, Magnus Höök, Dan B. Jones, and Kirk R. Wilhelmus. "The Collagen-Binding Adhesin Is a Virulence Factor in Staphylococcus aureus Keratitis." Infection and Immunity 68, no. 6 (June 1, 2000): 3776–79. http://dx.doi.org/10.1128/iai.68.6.3776-3779.2000.
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ABSTRACT A collagen-binding strain of Staphylococcus aureusproduced suppurative inflammation in a rabbit model of soft contact lens-associated bacterial keratitis more often than its collagen-binding-negative isogenic mutant. Reintroduction of thecna gene on a multicopy plasmid into the mutant helped it regain its corneal adherence and infectivity. The topical application of a collagen-binding peptide before bacterial challenge decreasedS. aureus adherence to deepithelialized corneas. These data suggest that the collagen-binding adhesin is involved in the pathogenesis of S. aureus infection of the cornea.
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Nagy, Zoltan Z. "The Role of Femtolaser in Cataract Surgery." European Ophthalmic Review 06, no. 05 (2012): 286. http://dx.doi.org/10.17925/eor.2012.06.05.286.
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Femtolasers were recently introduced into the surgery of the crystalline lens after having great success in corneal surgery. The most important indications and features are: perfectly centred and sized capsulotomy, liquefaction of softer lenses, fragmentation of harder lenses to help chopping of the cataractous lens without phaco energy, and lastly to create corneal wound in any position and size and also to control pre-operative astigmatism using arcuate incisions in the desired depth within the cornea. As a result of controlled steps in cataract surgery wide acceptance and spread is to be expected.
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Afifah, Nabilah, Herwindo Dicky Putranto, and Lely Retno Wulandari. "A Challenging Management of Pseudomonas Perforated Corneal Ulcer with Multilayer Amniotic Membrane Transplantation and Pericardial Patch Graft in Pediatric Patient." Vision Science and Eye Health Journal 1, no. 1 (November 29, 2021): 22–27. http://dx.doi.org/10.20473/vsehj.v1i1.2021.22-27.
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Introduction: Pseudomonas aeruginosa (P. aeruginosa) is the leading cause of corneal ulcers in children 0 to 3 years of age compared to children in general. Case presentation: A two-months-old infant presented with whitish patches on the right eye two days before admission. A central corneal ulcer with a size of 7-mm x 7-mm accompanied by corneal thinning and melting was shown on the right cornea. It is was surrounded by greyish white creamy infiltrates. Corneal scraping showed Pseudomonas aeruginosa specimens. The cornea became perforate and crystalline lens extrusion was found at the day after intravenous ceftriaxone, levofloxacin eye drop, and cefazoline fortified eye drop administering. It might be caused by bacterial elastase and toxin which contributed to corneal damage. The patient was underwent a multilayer Amniotic Membrane Transplantation (AMT) combined with a pericardial patch graft due to corneal perforation. Two months post-AMT and pericardial patch graft the corneal perforation became entirely heal due to multilayer AMT, despite lysis of the pericardial patch graft. Corneal scar formation and reduction of vitreous opacity in ultrasound examination were shown. The patient was planned to undergo keratoplasty. Conclusions: Corneal ulcers due to Pseudomonas aeruginosa are highly destructive. The levels of infection, diagnostic, and therapeutic are still problems in pediatric patients. Lens extrusion and lysis of the pericardial patch graft are examples in this case. Keratoplasty is the definitive treatment for corneal ulcers with perforation; however, multilayer AMT combined with pericardial patch graft can be used as an alternative therapy to accelerate wound healing, reduce inflammation, and maintain the integrity of the eyeball.
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Ucgul Atilgan, Cemile, Pinar Kosekahya, Dilara Ozkoyuncu Kocabas, Mustafa Koc, and Yasin Sakir Goker. "Densitometric analysis of cornea in patients with neovascular age-related macular degeneration after intravitreal aflibercept loading dose." Therapeutic Advances in Ophthalmology 12 (January 2020): 251584142095085. http://dx.doi.org/10.1177/2515841420950857.
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Purpose: To evaluate the anatomic changes in the cornea and anterior segment following intravitreal aflibercept loading dose for neovascular age-related macular degeneration. Methods: The study included 40 eyes of 40 patients with neovascular age-related macular degeneration. Each patient underwent a loading dose of one injection per month for three consecutive doses of aflibercept (0.05 ml/2 mg). Before and after the loading dose, a record was made for each patient of corneal topography, anterior segment, corneal densitometry, and lens densitometry parameters with the Pentacam HR and specular microscopy parameters with a non-contact specular microscope. The data before and after the aflibercept loading dose were compared. Results: Corneal densitometry parameters in the 0- to 2-mm and 2- to 6-mm concentric zones of the posterior layer were significantly higher after the loading dose compared with baseline ( p = 0.03, p = 0.04, respectively). Corneal densitometry parameters of the anterior, central, and total corneal layer in the 10- to 12-mm concentric zone were also significantly higher after the loading dose compared with baseline ( p = 0.009, p = 0.02, and p = 0.007, respectively). No significant changes were determined in respect of corneal topography, anterior segment, lens densitometry, and specular microscopy parameters ( p > 0.05 for all). Conclusion: The aflibercept loading dose caused slightly increased densitometric values in some corneal regions while it did not affect the corneal topography, anterior segment, lens densitometry, and specular microscopy parameters.
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Bosco, L., G. Venturini, and D. Willems. "In vitro lens transdifferentiation of Xenopus laevis outer cornea induced by Fibroblast Growth Factor (FGF)." Development 124, no. 2 (January 15, 1997): 421–28. http://dx.doi.org/10.1242/dev.124.2.421.
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It has been shown that lens regeneration from outer cornea of larval Xenopus laevis is dependent on neural retina both in vivo and in tissue culture. The isolated outer cornea cultured in the presence of bovine brain-derived acidic Fibroblast Growth Factor (aFGF) is able to reprogram the differentiation into lens fibers, although this transdifferentiative process is not coupled with the formation of a normally organized lens. The capacity of aFGF to promote lens differentiation from cornea is not linked to its mitogenic activity. The cultured corneal cells can transdifferentiate into lens fibers in the presence of aFGF when DNA replication and cell proliferation are prevented by addition of aphidicolin, a specific inhibitor of DNA polymerase in eukaryotes, to the culture medium.
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Graham, Andrew D., and Meng C. Lin. "The relationship of pre-corneal to pre-contact lens non-invasive tear breakup time." PLOS ONE 16, no. 6 (June 28, 2021): e0247877. http://dx.doi.org/10.1371/journal.pone.0247877.
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Purpose To examine the relationship between pre-corneal and pre-contact lens tear film stability (TFS), and to determine whether pre-corneal TFS is a reliable predictor of subsequent pre-lens TFS after a contact lens is placed on the eye. Methods 667 records met inclusion criteria and were extracted from a soft contact lens multi-study database. Multivariable linear mixed effects models were fit to examine the association between pre-corneal and pre-lens TFS, adjusting for potential confounders and accounting for repeated measures. Receiver Operating Characteristic (ROC) analysis was employed to assess the predictive performance of pre-corneal TFS for subsequent pre-lens TFS. TFS was quantified for this analysis as the non-invasive tear breakup time (NITBUT). Results Pre-corneal NITBUT was significantly related to the pre-lens NITBUT at both 10 min (p<0.001) and 2–6 hrs (p<0.001) post-lens insertion. However, the sensitivities of pre-corneal NITBUT for predicting symptom-associated thresholds of pre-lens NITBUT ranged from 50–65%, and specificities ranged from 57–72%, suggesting poor-to-moderate diagnostic performance. Conclusions Despite the association of pre-corneal and pre-lens TFS, the inherent lability and sensitivity to environmental exposures of the tear film introduce significant variability into NITBUT measurements. Using pre-corneal NITBUT to identify likely successful contact lens candidates prior to fitting is thus not sufficiently accurate to be relied upon in the clinical setting.
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Zaman, Shah, Hussain Ibrar, Jan Sanaullah, Mahar P S, Ishaq Mazhar, and Rizvi Fawad. "Treatment of advance keratoconus using donor bowman layer: the zaman technique of bowman layer transplantation (Type I & Type II)." International Journal of Clinical and Experimental Ophthalmology 6, no. 1 (May 6, 2022): 015–25. http://dx.doi.org/10.29328/journal.ijceo.1001045.
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Commonly referred to as an ecstatic, non-inflammatory disease, Keratoconus, usually bilateral and asymmetric, is characterized by progressive steeping and thinning of the cornea. This results in irregular astigmatism which compromises vision [1,2]. Traditionally, early Keratoconus stages have been treated by prescribing a hard contact lens to obtain a regular anterior optical surface. This tendency was discontinued when contact lens intolerance in advanced stages required the use of penetrating keratoplasty (PKP) or deep anterior lamellar Keratoplasty (DALK). An alternative technique of corneal cross-linking was designed in 2003 as a treatment option for keratoconus. The cornea measured at least 400 um thickness after epithelium removal and pre-operative maximum keratometry (Kmax) measured 58D or less. As a result, no corneal transplantation was required or postponed [3].
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Wong, Anepmete, Melissa Fallon, Vildan Celiksoy, Salvatore Ferla, Carmine Varricchio, David Whitaker, Andrew J. Quantock, and Charles M. Heard. "A Composite System Based upon Hydroxypropyl Cyclodextrins and Soft Hydrogel Contact Lenses for the Delivery of Therapeutic Doses of Econazole to the Cornea, In Vitro." Pharmaceutics 14, no. 8 (August 4, 2022): 1631. http://dx.doi.org/10.3390/pharmaceutics14081631.
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Fungal keratitis, a disease in which the cornea becomes inflamed due to an invasive fungal infection, remains difficult to treat due in part to limited choices of available treatments. Topical eye drops are first-line treatment, but can be ineffective as low levels of drug reach the target site due to precorneal losses and the impenetrability of the cornea. The aim of this study was to determine the corneal delivery of econazole using a novel topical enhancement approach using a composite delivery system based upon cyclodextrins and soft hydrogel contact lenses. Excess econazole nitrate was added to hydroxypropyl-α-cyclodextrin (HP-α-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) solutions, and the solubility determined using HPLC. Proprietary soft hydrogel contact lenses were then impregnated with saturated solutions and applied to freshly enucleated porcine eyeballs. Econazole nitrate ‘eye drops’ at the same concentrations served as the control. After 6 h, the corneas were excised and drug-extracted, prior to quantification using HPLC. Molecular dynamic simulations were performed to examine econazole–HP-β-CD inclusion complexation and dissociation. The minimum inhibitory concentration (MIC) of econazole was determined against four fungal species associated with keratitis, and these data were then related to the amount of drug delivered to the cornea, using an average corneal volume of 0.19 mL. The solubility of econazole increased greatly in the presence of HP-β-CD and more so with HP-α-CD (p < 0.001), with ratios >> 2. Hydrogel contact lenses delivered ×2.8 more drug across the corneas in comparison to eye drops alone, and ×5 more drug delivered to the cornea when cyclodextrin was present. Molecular graphics demonstrated dynamic econazole release, which would create transient enhanced drug concentration at the cornea surface. The solution-only drops achieved the least satisfactory result, producing sub-MIC levels with factors of ×0.81 for both Fusarium semitectum and Fusarium solani and ×0.40 for both Scolecobasidium tshawytschae and Bipolaris hawaiiensis. All other treatments delivered econazole at > MIC for all four fungal species. The efficacies of the delivery platforms evaluated were ranked: HP-α-CD contact lens > HP-β-CD contact lens > contact lens = HP-α-CD drops > HP-β-CD drops > solution-only drops. In summary, the results in this study have demonstrated that a composite drug delivery system based upon econazole–HP-β-CD inclusion complexes loaded into contact lenses can achieve significantly greater corneal drug delivery with the potential for improved clinical responses.
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Kaluzny, Bartlomiej J., Joanna Stachura, Patryk Mlyniuk, Alfonso Jimenez-Villar, Magdalena Wietlicka-Piszcz, and Ireneusz Grulkowski. "Change in the geometry of positive- and negative-powered soft contact lenses during wear." PLOS ONE 15, no. 11 (November 9, 2020): e0242095. http://dx.doi.org/10.1371/journal.pone.0242095.
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Contact lens wear causes mutual interactions between the ocular surface and the lens, which may affect comfort as well as vision. The aim of this study was to examine deformations in modern positive- and negative-powered silicone hydrogel soft contact lenses (SiH SCLs) after 7 days of continuous wear. This pre-post interventional study included 64 eyes: 42 eyes with myopia of -3.00 D and 22 eyes with hyperopia of +3.00 D. All patients underwent general ophthalmic examination, corneal topography/tomography, total corneal and epithelial thickness mapping, and specular microscopy before and after the wearing period. SiH SCLs made of senofilcon A were worn continuously for 7 days on all eligible eyes. The geometry of the new and used lenses was measured 3 to 6 minutes after removal in two perpendicular planes using a custom-made swept source optical coherence tomography (SS-OCT) system for in vitro measurements. The anterior and posterior radii of curvature decreased in -3.00 D lenses in two perpendicular planes. This effect correlated significantly with average keratometry of the cornea. Sagittal lens height was lower in +3.00 D lens after wear, which correlated moderately with the corneal sagittal height. A significant decrease in central corneal epithelial thickness was observed after wearing +3.0 D lenses. In conclusion, SiH SCLs made of senofilcon A undergo minor deformations after 7-day continuous wear. Geometry modifications are different for -3.00 D and +3.00 D lenses, and they imitate the shape of the anterior eye surface. These geometric changes are accompanied by a decrease in the central thickness of corneal epithelium after +3.00 D lens wear.
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Catherine Bastion, Mae-Lynn. "Evaluation of the Relationship between Corneal Diameter and Lens Diameter in Children." Medicine & Health 15, no. 2 (December 31, 2020): 66–84. http://dx.doi.org/10.17576/mh.2020.1502.09.
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Primary intraocular lens (IOL) implantation has gained acceptance for management of infantile cataracts because of the advantage of reduced amblyopia risk. The aim of the study was to investigate the association between corneal diameter as measured from the white-to-white distance and natural lens diameter in children. This association may aid intraocular lens selection following cataract removal in infants and young children. A cross-sectional study was performed on forty eyes from 40 children less than 4 years, who needed to be examined, were planned for a procedure or operation under general anaesthesia. Subjects were recruited from Eye Clinic,Kuala Lumpur General Hospital from January 2010 to September 2011. Corneal diameter was measured with Holladay-Godwin corneal gauge while lens diameter was measured with ultrasound biomicroscope (UBM) during surgery. For the results, mean age of subjects was 24.7 + 12.1 months. Mean corneal diameter was 11.62 + 0.50 mm horizontally and 11.20 + 0.58 mm vertically. Mean horizontal lens diameter was 7.94 + 0.47 mm. A medium positive correlation was found between mean horizontal corneal diameter and lens diameter (r=0.479, p=0.002). Lens diameter had a strong correlation with patient’s age (r=0.718, p<0.001). Lens diameter can be calculated by using this model of equation: [Lens diameter (mm) = 7.010 + 0.021 Corneal Diameter (mm) + 0.028 Age (months)] (r2=0.52). In conclusion, there was a moderate positive correlation between corneal and lens diameter. UBM can be used to measure lens capsular bag size directly preoperatively.
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Ortenberg, Ilya, and Shmuel Behrman. "The Role of Scleral Lens in Ectatic Corneas." International Journal of Keratoconus and Ectatic Corneal Diseases 2, no. 1 (2013): 28–30. http://dx.doi.org/10.5005/jp-journals-10025-1044.
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ABSTRACT Scleral contact lenses can manage in treatment of keratoconus and ectatic corneal diseases. This article will review history, fitting technique and future of scleral lenses. How to cite this article Ortenberg I, Behrman S. The Role of Scleral Lens in Ectatic Corneas. Int J Kerat Ect Cor Dis 2013;2(1):28-30.
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Ortenberg, Ilya, and Shmuel Behrman. "The Role of Scleral Lens in Ectatic Corneas." International Journal of Keratoconus and Ectatic Corneal Diseases 2, no. 1 (2013): 31–33. http://dx.doi.org/10.5005/jp-journals-10025-1045.
Full textAbstract:
ABSTRACT Scleral contact lenses can manage in treatment of keratoconus and ectatic corneal diseases. This article will review history, fitting technique and future of scleral lenses. How to cite this article Ortenberg I, Behrman S. The Role of Scleral Lens in Ectatic Corneas. Int J Kerat Ect Cor Dis 2013;2(1):28-30.
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Walker, Thomas D. "Soft corneal lens infection." Medical Journal of Australia 143, no. 4 (August 1985): 174. http://dx.doi.org/10.5694/j.1326-5377.1985.tb122897.x.
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