Journal articles: 'Full-field ERG'

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Hochstein, Grant D., Fanni E. Molnar, and Michael F. Marmor. "Intrasession variability of the full-field ERG." Documenta Ophthalmologica 115, no. 2 (May 9, 2007): 77–83. http://dx.doi.org/10.1007/s10633-007-9057-x.

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Hood, Donald C., William Seiple, Karen Holopigian, and Vivienne Greenstein. "A comparison of the components of the multifocal and full-field ERGs." Visual Neuroscience 14, no. 3 (May 1997): 533–44. http://dx.doi.org/10.1017/s0952523800012190.

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AbstractThe multi-input technique of Sutter and Tran (1992) yields multiple focal ERGs. The purpose here was to compare the components of this multifocal ERG to the components of the standard, full-field ERG. To record multifocal ERGs, an array of 103 hexagons was displayed on a monitor. Full-field (Ganzfeld) ERGs were elicited by flashes presented upon steady background fields. The latencies of two prominent subcomponents of the full-field ERG were altered by varying the intensity of the incremental flash or the intensity of the background field. By showing that similar manipulations of the multi-input parameters produce similar changes in latency, we were able to relate the components of the multifocal ERG to the components of the full-field ERG. The biphasic responses of the multifocal ERG appear to be generated by the same cells generating the a-wave and positive peaks of the full-field cone ERG.

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Tzekov, Radouil. "Full-field ERG in diabetic retinopathy: a screening tool?" Graefe's Archive for Clinical and Experimental Ophthalmology 253, no. 7 (May 9, 2015): 987–88. http://dx.doi.org/10.1007/s00417-015-3037-8.

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Machida, Shigeki, Kunifusa Tamada, Taku Oikawa, Yasutaka Gotoh, Tomoharu Nishimura, Muneyoshi Kaneko, and Daijiro Kurosaka. "Comparison of Photopic Negative Response of Full-Field and Focal Electroretinograms in Detecting Glaucomatous Eyes." Journal of Ophthalmology 2011 (2011): 1–11. http://dx.doi.org/10.1155/2011/564131.

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Purpose. To compare the photopic negative response (PhNR) of the full-field electroretinogram (ERG) to the PhNR of the focal ERGs in detecting glaucoma.Methods. One hundred and three eyes with glaucoma and 42 normal eyes were studied. Full-field ERGs were elicited by red stimuli on a blue background. The focal ERGs were elicited by a15∘white stimulus spot centered on the macula, the superotemporal or the inferotemporal areas of the macula.Results. In early glaucoma, the areas under the receiver operating characteristic curves (AUCs) were significantly larger for the focal PhNR (0.863–0.924) than those for the full-field PhNR (0.666–0.748) (P<.05). The sensitivity was significantly higher for the focal PhNR than for the full-field PhNR in early (P<.01) and intermediate glaucoma (P<.05). In advanced glaucoma, there was no difference in the AUCs and sensitivities between the focal and full-field PhNRs.Conclusions. The focal ERG has the diagnostic ability with higher sensitivity in detecting early and intermediate glaucoma than the full-field ERG.

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Blum, Maren-Christina, Lilly Leydolph, and Sascha Klee. "Influence of electric field orientation on the effect of ocular current stimulation using full field electroretinogram." Current Directions in Biomedical Engineering 7, no. 2 (October 1, 2021): 167–70. http://dx.doi.org/10.1515/cdbme-2021-2043.

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Abstract Ocular current stimulation (CS) exhibits potential for the treatment of neurodegenerative ocular diseases. For a full field electroretinogram (ffERG) we found no CS effect on the characteristic waves (a-wave, b’-wave, and b-wave). To investigate whether the orientation of the generated electric field has an influence on the CS effect, this study repeated the previous ffERG study with changing one CS electrode position and compared the results of both studies. In the first study 15 (8 m, 27.5 ± 4.5 years) and in the second study 17 (7 m, 22.0 ± 1.9 years) healthy volunteers were stimulated with an anodal, cathodal, and sham direct CS of 800 μA for 5 min in three sessions (randomized, different days). For both studies, a cut-sized ring rubber electrode was placed around the eye. A square rubber electrode was placed for the first study at the ipsilateral temple and for the second study at the visual cortex. Before (ERG 1) and during (ERG 2) the CS, the ffERG was measured. For both studies, the difference between the ERG 1 and ERG 2 measurement (CS effect) for the three characteristic waves was analyzed and compared between the studies. For statistical analysis, the Mann-Whitney U test with Bonferroni correction was applied (α = 0.05). The comparison of the data distribution showed only slight differences between the studies. The Mann-Whitney U test found no significant difference of the CS effect between the studies for all amplitudes and CS groups (p ≥ 0.0055). In the mean, the latency differences were smaller than the time resolution, therefore no statements for latency effects were possible. It can be concluded that the retinal cells generating the ffERG are not affected by ocular CS in either electrode montages tested.

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Ponjavic, Vesna, Lotta Granse, Elisabeth Bengtsson Stigmar, and Sten Andreasson. "Reduced full-field electroretinogram (ERG) in a patient treated with methotrexate." Acta Ophthalmologica Scandinavica 82, no. 1 (February 2004): 96–99. http://dx.doi.org/10.1046/j.1600-0420.2003.00181.x.

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Robson, A. G., C. Pavesio, E. M. Graham, and G. E. Holder. "The role of pattern ERG and full-field ERG in the characterisation and management of birdshot chorioretinopathy." Clinical Neurophysiology 118, no. 5 (May 2007): e166-e167. http://dx.doi.org/10.1016/j.clinph.2006.07.270.

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Schieding, Nikola, Thomas Reuter, Andreas Grundmann, Sebastian Walther, and Sascha Klee. "Full-field electroretinography examinations of the human eye with the eye diagnostic device PEP-2000 – First results." Current Directions in Biomedical Engineering 8, no. 2 (August 1, 2022): 636–39. http://dx.doi.org/10.1515/cdbme-2022-1162.

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Abstract Full-field electroretinography (full-field ERG) forms the diagnostic basis for numerous pathologies of the eye. For this reason, fast and accurate diagnostics in the field of ophthalmology are essential. Two examination techniques, full-field ERG and pupillometry were combined in a diagnostic device developed by ICM e.V. to reduce the examination process for both examiners and patients. In this paper, the device is examined for the quality of the full-field ERG measurements. A feasibility study with 12 healthy subjects (3 f, 9 m, 36.33 ± 11.94 years) was conducted to evaluate the device. The results showed that the peak times for both light- and dark-adapted measurements were within the range of the researched literature values. However, the amplitudes were markedly lower in both measurements compared to the averaged literature values (dark-adapted about 8.5-fold and light-adapted about 5.5-fold) and are clearly outside the range of values researched. The main reason for this is the use of cup electrodes, which were placed on the skin of the lower eyelid. Nevertheless, plausible and comparable analysis values could be obtained with the eye diagnostic device PEP-2000. Further studies with wire electrodes will be performed.

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Safatle, Angélica M. V., Ana Paula Hvenegaard, Denise Otsuki, Terezinha L. Martins, Márcia Kahvegian, Adriana Berezovsky, Solange R. Salomão, and Paulo S. M. Barros. "Comparison of full-field electroretinogram in diabetic and non diabetic dogs with cataracts." Pesquisa Veterinária Brasileira 30, no. 12 (December 2010): 1071–76. http://dx.doi.org/10.1590/s0100-736x2010001200012.

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Being the commonest ocular disorder, dense cataracts disable fundoscopic examination and the diagnosis of retinal disorders, which dogs may be predisposed. The aim of this study was to compare the electroretinographic responses recorded according to the International Society for Clinical Electrophysiology of Vision human protocol to evaluate retinal function of diabetic and non diabetic dogs, both presenting mature or hypermature cataracts. Full-field electroretinogram was recorded from 66 dogs, with ages varying from 6 to 15 years old allocated into two groups: (1) CG, non diabetic cataractous dogs, and (2) DG, diabetic cataractous dogs. Mean peak-to-peak amplitude (microvolts) and b-wave implicit time (milliseconds) were determined for each of the five standard full-field ERG responses (rod response, maximal response, oscillatory potentials, single-flash cone response and 30 Hz flicker). Comparing CG to DG, ERGs recorded from diabetic dogs presented lower amplitude and prolonged b-wave implicit time in all ERG responses. Prolonged b-wave implicit time was statistically significant (p< 0.05) at 30 Hz flicker (24.0 ms versus 22.4 ms). These data suggests full-field ERG is capable to record sensible alterations, such as flicker's implicit time, being useful to investigate retinal dysfunction in diabetic dogs.

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Granse, Lotta, Vesna Ponjavic, and Sten Andreasson. "Full-field ERG, multifocal ERG and multifocal VEP in patients with retinitis pigmentosa and residual central visual fields." Acta Ophthalmologica Scandinavica 82, no. 6 (December 2004): 701–6. http://dx.doi.org/10.1111/j.1600-0420.2004.00362.x.

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Schmid, Katrina L., Cassie L. Rayner, and Brian Brown. "Hemi-field and full-field form-deprivation induce timing changes in multifocal ERG responses in chick." Ophthalmic and Physiological Optics 33, no. 3 (May 2013): 257–66. http://dx.doi.org/10.1111/opo.12055.

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Marmor, Michael F., Lorella Cabael, Shefalee Shukla, John C. Hwang, and Mira Marcus. "Clinical S-cone ERG recording with a commercial hand-held full-field stimulator." Documenta Ophthalmologica 109, no. 1 (July 2004): 101–7. http://dx.doi.org/10.1007/s10633-004-3299-7.

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Karagiannis, Dimitrios, Georgios A. Kontadakis, Artemios S. Kandarakis, Nikolaos Markomichelakis, Ilias Georgalas, Efstratios A. Parikakis, and Stamatina A. Kabanarou. "Acute Zonal Occult Outer Retinopathy with Atypical Findings." Case Reports in Medicine 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/290696.

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Background. To report a case of acute zonal occult outer retinopathy (AZOOR) with atypical electrophysiology findings.Case Presentation. A 23-year-old-female presented with visual acuity deterioration in her right eye accompanied by photopsia bilaterally. Corrected distance visual acuity at presentation was 20/50 in the right eye and 20/20 in the left eye. Fundus examination was unremarkable. Visual field (VF) testing revealed a large scotoma. Pattern and full-field electroretinograms (PERG and ERG) revealed macular involvement associated with generalized retinal dysfunction. Electrooculogram (EOG) light rise and the Arden ratio were within normal limits bilaterally. The patient was diagnosed with AZOOR due to clinical findings, visual field defect, and ERG findings.Conclusion. This is a case of AZOOR with characteristic VF defects and clinical symptoms presenting with atypical EOG findings.

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Góes, Ana C. A., Tatiane Villar, Denise A. Otsuki, Ricardo Lisak, Ricardo A. Pecora, and Angélica M. V. Safatle. "Normal values of b-wave responses of full-field electroretinogram in Lhasa Apso dogs with cataracts according to age." Pesquisa Veterinária Brasileira 35, no. 3 (March 2015): 274–80. http://dx.doi.org/10.1590/s0100-736x2015000300011.

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Lhasa Apso dogs with immature, mature or hypermature cataracts were divided into four groups according to their age (G1: 1 to 3 years old, G2: 4 to 7 years old, G3: 8 to 11 years old, G4: more than 12 years old). All animals were evaluated under the same sedation protocol to allow the performance of the electroretinogram (ERG) exam to determine normal value of b-wave response of the full-field ERG according to age. Three ERG responses were recorded: rod, maximal and cone responses. The amplitude values and b-wave implicit time of the responses of all groups were compared and analyzed by Kruskal-Wallis test (variance analysis for non-repeated measures), followed by the Dunn post-test (when p<0,05). A significant decrease was observed in maximal responses' amplitude, when comparing the G4 group with G1 and G2. No statistically relevant differences were observed in the b-wave implicit time values between groups. The ERG values are directly influenced by the animal's age. Older patients presented a decrease in the amplitude of the maximal response. The study determined the normal parameters of ERG b-waves for Lhasa Apso dogs with cataract according to their age group.

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McCulloch, Daphne L., and Vasudevan Lakshminarayanan. "The Stiles–Crawford effect of the first kind and the full-field electroretinogram (ERG)." Journal of Modern Optics 56, no. 20 (November 20, 2009): 2176–80. http://dx.doi.org/10.1080/09500340903374169.

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Meredith, S. P., M. A. Reddy, L. E. Allen, A. T. Moore, and K. Bradshaw. "Full-field ERG responses recorded with skin electrodes in paediatric patients with retinal dystrophy." Documenta Ophthalmologica 109, no. 1 (July 2004): 57–66. http://dx.doi.org/10.1007/s10633-004-1752-2.

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Kjellström, Ulrika, Monica Lövestam-Adrian, Sten Andréasson, and Vesna Ponjavic. "Full-field ERG and visual fields in patients 5 years after discontinuing vigabatrin therapy." Documenta Ophthalmologica 117, no. 2 (January 10, 2008): 93–101. http://dx.doi.org/10.1007/s10633-007-9108-3.

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VARANO, L., F. CAMPAGNA, C. RUSSO, V. SCORCIA, GB SCORCIA, D. BRUZZICHESSI, S. PARISE, G. CARNOVALE SCALZO, and G. SCORCIA. "Full field ERG values before and after anti-VEFG treatment in AMD affected subjects." Acta Ophthalmologica Scandinavica 85 (October 2, 2007): 0. http://dx.doi.org/10.1111/j.1600-0420.2007.01062_3367.x.

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Tillman, Megan A., Athanasios Panorgias, and John S. Werner. "Age-related change in fast adaptation mechanisms measured with the scotopic full-field ERG." Documenta Ophthalmologica 132, no. 3 (April 28, 2016): 201–12. http://dx.doi.org/10.1007/s10633-016-9541-2.

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McCulloch, Daphne L., Mineo Kondo, Ruth Hamilton, Pierre Lachapelle, André M. V. Messias, Anthony G. Robson, and Shinji Ueno. "ISCEV extended protocol for the stimulus–response series for light-adapted full-field ERG." Documenta Ophthalmologica 138, no. 3 (March 30, 2019): 205–15. http://dx.doi.org/10.1007/s10633-019-09685-8.

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You, Yuyi, Elizabeth C. Graham, Ting Shen, Con Yiannikas, John Parratt, Vivek Gupta, Joshua Barton, et al. "Progressive inner nuclear layer dysfunction in non-optic neuritis eyes in MS." Neurology - Neuroimmunology Neuroinflammation 5, no. 1 (December 15, 2017): e427. http://dx.doi.org/10.1212/nxi.0000000000000427.

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Objective:To investigate primary retinal functional changes in non-optic neuritis (ON) eyes of patients with MS by full-field electroretinography (ERG).Methods:Seventy-seven patients with relapsing-remitting MS with no history of clinical ON in at least 1 eye and 30 healthy controls were recruited in the cohort study. Full-field ERGs were recorded, and retinal optical coherence tomography scans were performed to assess the thicknesses of peripapillary retinal nerve fiber layer (RNFL) and retinal ganglion cell layer–inner plexiform layer (GCL-IPL). Annual MRI scans were also carried out to evaluate the disease activity in the brain. Patients were followed up for 3 years.Results:At baseline, a delayed b-wave peak time was observed in the cone response (p < 0.001), which was associated with the thicknesses of RNFL and GCL-IPL. The peak time of the delayed b-wave also correlated with the Expanded Disability Status Scale, T2 lesion volume, and disease duration. During the 3-year follow-up, progressive ERG amplitude reduction was observed (both a- and b-waves, p < 0.05). There was a correlation between the b-wave amplitude reduction and longitudinal RNFL loss (p = 0.001). However, no correlation was found between longitudinal ERG changes and disease activity in the brain.Conclusions:This study demonstrated progressive inner nuclear layer dysfunction in MS. The borderline a-wave changes suggested some outer retinal dysfunction as well. The correlation between full-field ERG changes and retinal ganglion cell loss suggested that there might be subclinical retinal pathology in MS affecting both outer and inner retinal layers.

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Schwitzer, Thomas, Matthieu P. Robert, Anne Giersch, Karine Angioi-Duprez, Isabelle Ingster-Moati, Amandine Pon-Monnier, Raymund Schwan, and Vincent Laprevote. "Transient Retinal Dysfunctions after Acute Cannabis Use." European Addiction Research 22, no. 6 (2016): 287–91. http://dx.doi.org/10.1159/000446823.

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Although cannabis is very widespread worldwide, the impact of cannabis on visual function remains poorly understood. This is partly due to numerous difficulties met in developing clinical studies in cannabis users. Here, we report the first documented case of neuroretinal dysfunction after acute cannabis smoking. This observation was favored by the need of an annual ophthalmic evaluation in the context of a chloroquine intake for a systemic lupus erythematosus in a 47-year-old heavy cannabis user. A complete ophthalmic evaluation including visual acuity tests, intraocular pressure, fundoscopic examination, automated 10° central visual field, full-field electroretinogram (ERG) and multifocal ERG was performed twice - 30 min and 5 h after cannabis smoking. A strong decrease (up to 48%) in the a-wave amplitude of the full-field ERG was measured 30 min after cannabis smoking for all scotopic responses compared with the responses 5 h after smoking. Other tests showed reproducible results between the 2 series of measurements. This clinical case suggests that acute inhalation of cannabis affects the photoreceptors functioning. This rare situation suggests further investigations are required on the impact of cannabis on retinal processing, especially since cannabis has been incriminated in car injuries.

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VENTURA, DORA F., MARCELO T. V. COSTA, MARCELO F. COSTA, ADRIANA BEREZOVSKY, SOLANGE R. SALOMÃO, ANA LUÍZA SIMÕES, MARCOS LAGO, et al. "Multifocal and full-field electroretinogram changes associated with color-vision loss in mercury vapor exposure." Visual Neuroscience 21, no. 3 (May 2004): 421–29. http://dx.doi.org/10.1017/s0952523804213372.

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We evaluated the color vision of mercury-contaminated patients and investigated possible retinal origins of losses using electroretinography. Participants were retired workers from a fluorescent lamp industry diagnosed with mercury contamination (n= 43) and age-matched controls (n= 21). Color discrimination was assessed with the Cambridge Colour Test (CCT). Retinal function was evaluated by using the ISCEV protocol for full-field electroretinography (full-field ERG), as well as by means of multifocal electroretinography (mfERG). Color-vision losses assessed by the CCT consisted of higher color-discrimination thresholds along the protan, deutan, and tritan axes and significantly larger discrimination ellipses in mercury-exposed patients compared to controls. Full-field ERG amplitudes from patients were smaller than those of the controls for the scotopic responseb-wave, maximum response, sum of oscillatory potentials (OPs), 30-Hz flicker response, and light-adapted cone response. OP amplitudes measured in patients were smaller than those of controls for O2 and O3. Multifocal ERGs recorded from ten randomly selected patients showed smaller N1–P1 amplitudes and longer latencies throughout the 25-deg central field. Full-field ERGs showed that scotopic, photopic, peripheral, and midperipheral retinal functions were affected, and the mfERGs indicated that central retinal function was also significantly depressed. To our knowledge, this is the first demonstration of retinal involvement in visual losses caused by mercury toxicity.

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Yang, Jung-Je, Chu-Hsuan Huang, Chang-Hao Yang, Chung-May Yang, Chao-Wen Lin, Tzyy-Chang Ho, Chang-Ping Lin, et al. "The Clinical Contribution of Full-Field Electroretinography and 8-Year Experiences of Application in a Tertiary Medical Center." Journal of Personalized Medicine 11, no. 10 (October 12, 2021): 1022. http://dx.doi.org/10.3390/jpm11101022.

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Electroretinography (ERG) is an important and well-established examination for retinal and visual pathway diseases. This study reviewed the medical records of patients who received full-field ERG (ffERG) at a single medical center between 2012 and 2019, which was an 8-year experience in the clinical contribution of ERG. Based on the indication for scheduling ffERG and the final diagnosis, patients could be classified into six groups: ‘retinal dystrophies’, ‘other retinal or macular diseases’, ‘optic neuropathies’, ‘visual complaints’, ‘systemic diseases’, and ‘others’. A total of 1921 full-field electroretinograms (ffERGs) (1655 patients) were included. The average number of ffERGs performed per year was 262 and the number of annual ffERGs was constant. The ‘retinal dystrophies’ group accounted for 36.5% of the studied population, followed by the ‘other retinal or macular diseases’ group (20.2%). The most common systemic disease was central nervous system disease. The rates of abnormal ffERGs in the ‘systemic diseases’, ‘optic neuropathies’, and ‘visual complaints’ groups were 27.3%, 22.6%, and 10.1%, respectively (p < 0.001). Higher rates were found in patients <20 years old in the ‘systemic diseases’ and ‘optic neuropathies’ groups; epilepsy and optic nerve atrophy were the most common diagnoses, respectively. In brief, by quantifying the functional response in the retina, ffERG is indispensable for diagnosis and prognosis in ophthalmologic and multidisciplinary practice.

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Birch, D. G., and D. C. Hood. "The full-field ERG as an outcome measure for treatment trials in hereditary retinal diseases." Journal of Vision 2, no. 10 (December 1, 2002): 107. http://dx.doi.org/10.1167/2.10.107.

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Teixeira, C., A. Rocha-Sousa, D. Trump, E. Brandäo, and F. Falcäo-Reis. "Identification of XLRS1 Gene Mutation (608C>T) in a Portuguese Family with Juvenile Retinoschisis." European Journal of Ophthalmology 15, no. 5 (September 2005): 638–40. http://dx.doi.org/10.1177/112067210501500515.

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Purpose To characterize electroretinogram (ERG) and molecular genetic findings in a family with XLRS1 mutation. The authors present two cases of a Portuguese family with juvenile retinoschisis with a mutation in exon 6. Methods Two brothers and their parents, grandmother, and uncle underwent a full ophthalmic examination. The two brothers with ophthalmic disease were evaluated with color fundus photography, fluorescein angiography, optical coherence tomography (OCT), molecular genetic study (Group VI of Retinoschisis Consortium), pattern visual evoked potential (PVEP), and full field ERG. Results Both patients presented funduscopic manifestations of vitreoretinal degeneration. They presented peripheral schisis and retinal detachment. However, foveal schisis had never been observed at funduscopy. A negative ERG was recorded in both. Six months after that, the younger brother showed a typical foveal schisis at fundus examination. A retinoschisis gene (XLRS1) mutation with transition of cytosine by thymine at position 608 (608C>T) had been identified in both. Conclusions Negative ERG is the most secure clinical marker to establish the diagnosis of juvenile retinoschisis. XLRS1 gene 608C>T mutation was described for the first time in a Portuguese family.

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Değirmenci, Mehmet Fatih Kağan, Sibel Demirel, Figen Batıoğlu, and Emin Özmert. "Role of a mydriasis-free, full-field flicker ERG device in the detection of diabetic retinopathy." Documenta Ophthalmologica 137, no. 3 (October 17, 2018): 131–41. http://dx.doi.org/10.1007/s10633-018-9656-8.

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Drazek, M., M. Lew, S. Lew, and A. Pomianowski. "Electroretinography in dogs: a review ." Veterinární Medicína 59, No. 11 (December 9, 2014): 515–26. http://dx.doi.org/10.17221/7816-vetmed.

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Electroretinography (ERG) in the form of full-field, flash ERG is the most commonly used technique in veterinary ophthalmology for diagnosing the functioning of the outer retina. Under light stimulation spatially distributed different cell types within the retina produce time-varying electric responses. These are recorded in the form of ERG traces consisting of a series of positive and negative wavelets. The possibility of selective stimulation of individual types of retinal cells and the analysis of constituent components of ERGs are the basis for determining the source of abnormalities and diagnosis of various types of dysfunction. In many cases, the ERG allows diagnosis of hereditary retinal disorders in dogs before the appearance of behavioural and ophthalmoscopic symptoms. This review is an introduction to the electrophysiology of vision, intended for small animal practitioners, and aimed at presenting the benefits of ERG for early ophthalmic diagnostics in dogs.

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Rubin, Glen R., Yuquan Wen, Michael S. Loop, and Timothy W. Kraft. "ERG and Behavioral CFF in Light-Damaged Albino Rats." International Journal of Molecular Sciences 23, no. 8 (April 8, 2022): 4127. http://dx.doi.org/10.3390/ijms23084127.

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The full-field ERG is useful for index rod- or cone-mediated retinal function in rodent models of retinal degeneration. However, the relationship between the ERG response amplitudes and visually guided behavior, such as flicker detection, is not well understood. A comparison of ERG to behavioral responses in a light-damage model of retinal degeneration allows us to better understand the functional implications of electrophysiological changes. Flicker-ERG and behavioral responses to flicker were used to determine critical flicker frequency (CFF) under scotopic and photopic conditions before and up to 90 d after a 10-day period of low-intensity light damage. Dark- and light-adapted ERG flash responses were significantly reduced after light damage. The a-wave was permanently reduced, while the b-wave amplitude recovered over three weeks after light damage. There was a small, but significant dip in scotopic ERG CFF. Photopic behavioral CFF was slightly lower following light damage. The recovery of the b-wave amplitude and flicker sensitivity demonstrates the plasticity of retinal circuits following photopic injury.

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Zolnikova, I. V., V. V. Kadyshev, A. V. Marakhonov, A. B. Chernyak, S. V. Milash, Yu A. Bobrovskaya, N. A. Urakova, N. Sh Kokoeva, S. I. Kutsev, and R. A. Zinchenko. "Clinical and Genetic Correlations of Inherital Retinal Disease with Mutations in the ABCA4 Gene by Patients of the Russian Population." Ophthalmology in Russia 18, no. 4 (December 29, 2021): 897–907. http://dx.doi.org/10.18008/1816-5095-2021-4-897-907.

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Aim: to study genotype-phenotype correlations in patients with inherited retinal diseases with mutations in ABCA4 gene in Russian Federation.Patients and methods. 21 patients from Russian population aged from 7 to 51 years old (mean age 20 ± 11 years with best-corrected visual acuity from 0,02 to 0,6 (0,14 ± 0,11) with ABCA4-associated retinopathy, verified by molecular genetics methods. All patients besides standard ophthalmic examination and photodocumentation were performed Spectral-Domain OCT and fundus autofluorescence on Spectralis ®HRA+OCT (Heidelberg Engineering, Germany). Full-field electroretinogram (ERG), 30-Hz flicker ERG and macular chromatic ERG (MERG) to red stimulus were recorded on electroretinographic system MBN (MBN, Russia). (Russia) Molecular genetic studies were performed using Next Generation Sequencing (NGS) and Sandger direct sequencing. Results: In ABCA4-associated Stargardt disease 1 type (STGD1) genotype [p.L541P, p.A1038V] of «frequent» mutations was revealed in 9 patients, in 2 cases in was associated another “frequent” mutation p.G1961E. In 4 patients with genotype [p.L541P, p.A1038V] “severe” phenotype of Stargardt disease was found: with large defect of the ellipsoid zone and large zone of central reduced autofluorescence, severely subnormal macular ERG (MERG) to red stimulus and subnormal 30 Hz flicker and full-field maximal ERG. In one patient with these mutations in homozygous state ABCA4-associated cone-rod dystrophy (CORD3, clinically looking alike secondary retinal dystrophy is diagnosed. In 2 patients with genotype [p.L541P, p.A1038V] and mutation p.G1961E was found mild phenotype. One patient with homozygous mutation p.R653C autosomal recessive ABCA4-associated retinitis pigmentosa (RP19) was diagnosed. Clinical picture and autofluorescence were polymorphic in all patients.Conclusions. Our study with ophthalmological, molecular genetics and instrumental methods widens the spectrum of clinical signs of inherited eye diseases associated with mutations in АВСА4 gene, widens the spectrum mutations in Russian Federation and reveals clinicо-genetic genotype-phenotype correlations.

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Kato, Kumiko, Mineo Kondo, Masahiko Sugimoto, Kengo Ikesugi, and Hisashi Matsubara. "Effect of Pupil Size on Flicker ERGs Recorded With RETevalSystem: New Mydriasis-Free Full-Field ERG System." Investigative Opthalmology & Visual Science 56, no. 6 (June 5, 2015): 3684. http://dx.doi.org/10.1167/iovs.14-16349.

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Eksandh, Louise, Vesna Ponjavic, Patricia B. Munroe, Hans Eiberg, Paul Uvebrant, Berndt Ehinger, Sara E. Mole, and Sten Andréasson. "Full-field ERG in patients with Batten/Spielmeyer-Vogt disease caused by mutations in the CLN3 gene." Ophthalmic Genetics 21, no. 2 (January 2000): 69–77. http://dx.doi.org/10.1076/1381-6810(200006)2121-8ft069.

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Eksandh, Louise, Vesna Ponjavic, Patricia B. Munroe, Hans Eiberg, Paul Uvebrant, Berndt Ehinger, Sara E. Mole, and Sten Andr�asson. "Full-field ERG in patients with Batten/Spielmeyer-Vogt disease caused by mutations in the CLN3 gene." Ophthalmic Genetics 21, no. 2 (June 1, 2000): 69–77. http://dx.doi.org/10.1076/1381-6810(200006)21:2;1-8;ft069.

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Johnson, Mary A., Brett G. Jeffrey, André M. V. Messias, and Anthony G. Robson. "ISCEV extended protocol for the stimulus–response series for the dark-adapted full-field ERG b-wave." Documenta Ophthalmologica 138, no. 3 (March 30, 2019): 217–27. http://dx.doi.org/10.1007/s10633-019-09687-6.

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Perlman, Ido, Mineo Kondo, Enid Chelva, Anthony G. Robson, and Graham E. Holder. "ISCEV extended protocol for the S-cone ERG." Documenta Ophthalmologica 140, no. 2 (November 20, 2019): 95–101. http://dx.doi.org/10.1007/s10633-019-09730-6.

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AbstractThe International Society for Clinical Electrophysiology of Vision (ISCEV) standard for full-field electroretinography (ERG) describes a minimum procedure for testing generalized retinal function but encourages more extensive testing. This extended protocol describes a method of assessing the function of the short-wavelength-sensitive cone (S-cone) retinal pathway, using a short-wavelength flash superimposed on a background that saturates the rods and adapts the L/M-cones to elicit a response, known as the S-cone ERG. Stimulus parameters such as the strength and luminance of the flash and background, respectively, and their spectral and temporal characteristics are specified. As a complement to the ISCEV standard, testing the S-cone ERG enables further characterization of light-adapted retinal function and may refine diagnosis of some retinal disorders. Typical applications are described including use in the diagnosis of rod monochromacy and S-cone monochromacy, identification and investigation of cone On-bipolar cell dysfunction and use of the technique to confirm the diagnosis of enhanced S-cone syndrome.

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McANANY, J. JASON, and KENNETH R. ALEXANDER. "Is there an omitted stimulus response in the human cone flicker electroretinogram?" Visual Neuroscience 26, no. 2 (March 2009): 189–94. http://dx.doi.org/10.1017/s0952523808080991.

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AbstractOmitting a stimulus from a train of repetitive stimuli, by either interrupting or terminating the train, can elicit an electrophysiological response that occurs at the time appropriate for the omitted stimulus. This study investigated whether such an omitted stimulus response (OSR) is present in the flicker electroretinogram (ERG) of the human cone system. ERGs were recorded from 11 visually normal subjects in response to full-field sinusoidal flicker trains presented against a rod-desensitizing adapting field at frequencies ranging from 12.5 to 100 Hz. Recordings were synchronized with the onset of the stimulus trains, and the amplitude and relative delay of any additional ERG responses following the offset of the flicker train were analyzed. At stimulus frequencies below 35 Hz, the number of ERG responses always equaled the number of stimulus cycles. However, over the frequency range of 38.5 to 100 Hz, the ERG contained an extra response following flicker train offset. At stimulus frequencies from 38.5 to 62.5 Hz, there was a constant delay between the peak of the extra ERG response and the time at which the next stimulus would have occurred had the flicker train continued. This constant delay is characteristic of an OSR. In addition, an extra ERG response was apparent at these same stimulus frequencies if the flicker train was interrupted by omitting stimulus cycles from the middle of the train. The pattern of ERG findings is consistent with a recently proposed model of the OSR that attributes the phenomenon to a resonant oscillation in retinal bipolar cells.

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Rösch, Sarah, Sandra Johnen, Frank Müller, Christiane Pfarrer, and Peter Walter. "Correlations between ERG, OCT, and Anatomical Findings in therd10Mouse." Journal of Ophthalmology 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/874751.

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Background. To evaluate the correlation between ERG, OCT, and microscopic findings in therd10mouse.Methods. C57BL/6J wild type mice andrd10mice were compared at the age of 2, 3, 5, 7, 9, 12, 24, and 48 weeks (each age groupn=3) using full-field electroretinography (ERG), spectral domain Optical Coherence Tomography (sd-OCT), fluorescein angiography (FA), Hematoxylin & Eosin histology (HE), and immunohistology (IH).Results. While in wild type mice, the amplitude of a- and b-wave increased with light intensity and with the age of the animals, therd10mice showed extinction of the ERG beginning with the age of 5 weeks. In OCT recordings, the thickness of the retina decreased up to 9 weeks of age, mainly based on the degradation of the outer nuclear layer (ONL). Afterwards, the ONL was no longer visible in the OCT. HE staining and immunohistological findings confirmed thein vivodata.Conclusion. ERG and OCT are useful methods to evaluate the retinal function and structurein vivo. The retinal changes seen in the OCT closely match those observed in histological staining.

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Brigell, Mitchell, Brett G. Jeffrey, Omar A. Mahroo, and Radouil Tzekov. "ISCEV extended protocol for derivation and analysis of the strong flash rod-isolated ERG a-wave." Documenta Ophthalmologica 140, no. 1 (January 4, 2020): 5–12. http://dx.doi.org/10.1007/s10633-019-09740-4.

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AbstractThe International Society for the Clinical Electrophysiology of Vision (ISCEV) standard for full-field electroretinography (ERG) describes a minimum set of tests, but encourages the use of additional protocols for clinical ERG testing. This extended protocol describes recording methods and derivations that will allow analysis of rod-driven components of the dark-adapted (DA) strong flash ERG a-wave, more closely related to rod phototransduction than ISCEV standard DA ERGs. The method involves recording ERGs to a flash strength equivalent to 30 cd s m2 under conditions of dark adaptation and additionally to the same stimulus following light adaptation (LA) and in the presence of a standard photopic background luminance of 30 cd m−2. The isolated rod-driven ERG a-wave is derived by subtracting the LA response from the DA ERG. The method is likely to be of value in the characterization of retinal disorders which affect rod quantal catch, diseases that affect the dynamics of any component of the activation phase of rod phototransduction, or those affecting total numbers of rod photoreceptors.

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GOWRISANKARAN, SOWJANYA, J. JASON McANANY, and KENNETH R. ALEXANDER. "Poststimulus response characteristics of the human cone flicker electroretinogram." Visual Neuroscience 30, no. 4 (July 2013): 147–52. http://dx.doi.org/10.1017/s0952523813000333.

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AbstractAt certain temporal frequencies, the human cone flicker electroretinogram (ERG) contains multiple additional responses following the termination of a flicker train. The purpose of this study was to determine whether these poststimulus responses are a continuing response to the terminated flicker train or represent the oscillation of a resonant system. ERGs were recorded from 10 visually normal adults in response to full-field sinusoidally modulated flicker trains presented against a short-wavelength rod-saturating adapting field. The amplitude and timing properties of the poststimulus responses were evaluated within the context of a model of a second-order resonant system. At stimulus frequencies between 41.7 and 71.4 Hz, the majority of subjects showed at least three additional ERG responses following the termination of the flicker train. The interval between the poststimulus responses was approximately constant across stimulus frequency, with a mean of 14.4 ms, corresponding to a frequency of 69.4 Hz. The amplitude and timing characteristics of the poststimulus ERG responses were well described by an underdamped second-order system with a resonance frequency of 70.3 Hz. The observed poststimulus ERG responses may represent resonant oscillations of retinal ON bipolar cells, as has been proposed for electrophysiological recordings of poststimulus responses from retinal ganglion cells. However, further investigation is required to determine the types of retinal neurons involved in the generation of the poststimulus responses of the human flicker ERG.

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Tzekov, Radouil, and Brian Madow. "Visual Electrodiagnostic Testing in Birdshot Chorioretinopathy." Journal of Ophthalmology 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/680215.

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Birdshot chorioretinopathy (BSCR) is a rare form of autoimmune posterior uveitis that can affect the visual function and, if left untreated, can lead to sight-threatening complications and loss of central vision. We performed a systematic search of the literature focused on visual electrophysiology studies, including electroretinography (ERG), electrooculography (EOG), and visual evoked potentials (VEP), used to monitor the progression of BSCR and estimate treatment efficacy. Many reports were identified, including using a variety of methodologies and patient populations, which makes a direct comparison of the results difficult, especially with some of the earlier studies using nonstandardized methodology. Several different electrophysiological parameters, like EOG Arden’s ratio and the multifocal ERG response densities, are reported to be widely affected. However, informal consensus emerged in the past decade that the full-field ERG light-adapted 30 Hz flicker peak time is one of the most sensitive electrophysiological parameters. As such, it has been used widely in clinical trials to evaluate drug safety and efficacy and to guide therapeutic decisions in clinical practice. Despite its wide use, a well-designed longitudinal multicenter study to systematically evaluate and compare different electrophysiological methods or parameters in BSCR is still lacking but would benefit both diagnostic and therapeutic decisions.

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Zolnikova, I. V., S. V. Milash, V. V. Kadyshev, A. B. Chernyak, D. V. Levina, R. A. Zinchenko, I. V. Egorova, E. A. Eremeeva, and S. Y. Rogova. "Choroideremia with Mutation in CHM Gene. Clinical Cases with Literature Review." Ophthalmology in Russia 16, no. 1 (March 30, 2019): 124–30. http://dx.doi.org/10.18008/1816-5095-2019-1-124-130.

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The purpose: to describe clinical cases of choroideremia with mutation in CHM gene with molecular genetic verification of the diagnosis. Methods. Two relatives: a patient aged 33 and his mother’s sibs aged 39 with a rare hereditary retinal disease — choroideremia were examined. Patients’ full ophthalmic examination including autorefractometry, visual acuity testing with full correction, tonometry, biomicroscopy, fundus examination and photo as well as kinetic perimetry were performed. Electrophysiological examination included maximal electroretinogram (ERG), ERG to 30 Hz flicker and macular ERG (MERG) that were registered with electroretinograph MBN (Russia). Family anamnesis was studied. Genetic examination was performed for the verification of the diagnosis and pathologic gene molecular. Results. In 33-year-old patient advanced stage was diagnosed: best corrected visual acuity (BCVA) was OU 0,9, visual field was constricted to 10 degrees in both eyes. High BCVA and subnormal MERG correlated with comparatively preserved foveal structure on OCT. There was the terminal stage of choroideremia: In 39 years old his mother’s sibs BCVA was 0,1 OU, constricted to 5 degrees in both eyes. Maximal ERG and ERG to 30 Hz flicker were nonrecordable. Low BCVA and nonrecordable MERG correlated with defected retinal layers and cystoids macular edema on OCT. In both patients we revealed previously described pathogenic variant of nucleotic sequence in 6 exon of CHM gene (chrX:85213886 G>A), causing nonsense-mutation (p.Arg267*, NM_000390.2) in hemizygous state. Conclusion. Etiopathogenetic approach in choroideremia diagnostics allows providing correct diagnosis, prevention and developing of new treatment methods considering etiological factor.

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Abdelkader, Mona, Mohamed Mamdouh, and Ayman Fawzy. "Evaluation of Macular Function after Vitrectomy in Diabetic Macular Edema." Journal of Advanced Plastic Surgery Research 5, no. 1 (December 28, 2021): 18–26. http://dx.doi.org/10.31907/2414-2093.2019.05.04.

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Purpose: To document the effects of successful vitrectomy on retinal function and anatomy in diabetic patients. Methods: Three-port pars plana vitrectomy with detachment of posterior vitrous face was performed in 30 eyes of 25 patients with diabetic macular oedema DME (11 male, 14 Female).For each patients, visual acuity (VA) examination, measurement of retinal thickness using optical coherence tomography (OCT), full field electro-retinogram (ERG) and multifocal eletroretinogram (MF-ERG) were performed before and 1week,1month and 3months after vitrectomy. Results: Mean postoperative visual acuity was significantly improved (P<0.05); mean retinal thickness was significantly (P=0.001 ) decreased after 3monthes of surgery (from 450±150 into 220±50 micron ) .b-wave amplitudes of all cone and rod responses of ERG were significantly decreased in all vitrectomized eyes after 1 week. At one month, rod response was still unimproved but improved after 3months. Reduction in foveal Function as well as in para-foveal areas detected in the MF-ERG within 1st month. Then, mean P1 wave amplitude of MF-ERG of central ring increased and mean P1 wave implicit time decreased. These changes of MF-ERG parameters observed 3 months after vitrectomy. Conclusion: Multifocal electroretinogram can be useful to provide objective criteria for functional evaluation before and after vitrectomy in diabetic oedema.

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Safatle, Angélica M. V., Ana Paula Hvenegaard, Débora Gomes, Daniela C. Leandro, Denise Otsuki, and Ricardo Lisak. "Importância do eletrorretinograma de campo total (Full field ERG) em cães da raça Cocker Spaniel Inglês portadores de catarata." Pesquisa Veterinária Brasileira 30, no. 2 (February 2010): 149–54. http://dx.doi.org/10.1590/s0100-736x2010000200009.

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Com o aumento do número de intervenções cirúrgicas para a remoção da catarata em cães, observa-se a necessidade de exames específicos que devem ser realizados antes da indicação cirúrgica. A catarata é uma das principais causas de cegueira em cães. Nos estágios mais avançados, impossibilita o exame fundoscópico e inviabiliza a observação de alterações retinianas como a atrofia progressiva da retina (APR), degeneração retiniana hereditária de acometimento bilateral que, quando diagnosticada, contra-indica a cirurgia. Com o intuito de reestabelecer a visão, o eletrorretinograma de campo total (Full field ERG) torna-se indispensável na avaliação pré-cirúrgica da remoção da catarata. Como os cães da raça Cocker Spaniel Inglês são predispostos à catarata e a degenerações retinianas, objetivamos neste estudo avaliar as respostas dos ERGs realizados nestes animais. Foram avaliados 136 eletrorretinogramas de cães da raça Cocker Spaniel Inglês (62 machos e 74 fêmeas, com idades entre 3 e 15 anos) no período de Setembro de 2004 a Maio de 2009. Todos os animais apresentavam baixa de visão e catarata durante o exame. O diagnóstico de degeneração retiniana foi baseado nos valores de amplitude pico a pico e tempo de culminação da onda-b nas 3 respostas (resposta escotópica de bastonetes, máxima resposta e resposta fotópica de cones), idade do paciente e estágio de maturação da catarata. Nos cães sem degeneração retiniana, a média da amplitude e do tempo de culminação nas três respostas obtidas foram, respectivamente: 71,55mV/65,15ms; 149,17mV/33,03ms; 31,06mV/27,90ms. Nos cães com degeneração retiniana, 38 animais apresentaram ERG extinto. Dentre os restantes que apresentavam baixas respostas, a média da amplitude e do tempo de culminação nas três respostas obtidas foram, respectivamente: 12,88mV/65,04ms; 24,16mV/36,25ms; 8,36mV/31,38ms. Foi observado que em 122 animais (89,7%) os exames eram compatíveis com diagnóstico de atrofia progressiva da retina. Frente aos resultados obtidos, conclui-se que os cães da raça Cocker Spaniel Inglês portadores de catarata devem ser submetidos ao eletrorretinograma de campo total antes da remoção cirúrgica devido à alta incidência de degeneração retiniana nesta raça.

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Han, Xin-Yao, Ji-Yang Tang, Lyu-Zhen Huang, Ran Tang, and Jin-Feng Qu. "A novel mutation of CYP4V2 gene associated with Bietti crystalline dystrophy complicated by choroidal neovascularization." International Journal of Ophthalmology 15, no. 6 (June 18, 2022): 940–46. http://dx.doi.org/10.18240/ijo.2022.06.11.

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AIM: To investigate the clinical characteristics and genetic features of a Bietti crystalline dystrophy (BCD) proband in a Chinese family. METHODS: A Chinese female diagnosed with BCD complicated by bilateral choroidal neovascularization (CNV) and her parents underwent complete ophthalmic examinations, including fundus autofluorescence (AF), fundus photography (FP), fundus fluorescein angiography (FFA), visual field testing, full-field electroretinography (ERG), optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). The sequencing of the CYP4V2 gene was performed to the whole family. RESULTS: Bilateral tiny glittering crystal-like deposits and differing extent of atrophy of the retinal pigment epithelium (RPE) were found in the posterior pole of her fundus. The diffuse hypo-fluorescence shown on AF images and window defects shown on FFA both indicated the atrophy of the RPE and choriocapillaris. OCT showed the thinning of the RPE and choriocapillaris layer, ellipsoid zone (EZ) band defect and CNV in both eyes. OCTA images proofed bilateral type 2 CNV. The visual field test showed central and paracentral scotoma. ERG showed a slightly decreased b-wave in scotopic ERG. Gene sequencing identified three mutations of the CYP4V2 gene, c.802_807del, c.810delT, and c.1388G>A. The mutation c.1388G>A was a novel substitution mutation. CONCLUSION: The novel mutation c.1388G>A may be a possible cause that could induce the clinical phenotype of BCD.

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PEACHEY, NEAL S., J. BRETT STANTON, and ALAN D. MARMORSTEIN. "Noninvasive recording and response characteristics of the rat dc-electroretinogram." Visual Neuroscience 19, no. 6 (November 2002): 693–701. http://dx.doi.org/10.1017/s0952523802196015.

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In response to light, the retinal pigment epithelium (RPE) generates a series of potentials that can be recorded using the dc-electroretinogram (dc-ERG). As these potentials can be related to specific cellular events, they provide information about RPE function and how that may be altered by disease or experimental manipulation. The purposes of the present study were to define a noninvasive means for recording the rat dc-ERG, to use this to define the stimulus–response properties of the major components, and to relate these results to measures of the rat electrooculogram (EOG). Parallel studies were conducted in two strains of rats (Long-Evans, LE; Sprague-Dawley, SD) that are commonly used in vision research. Rats were sedated with ketamine/xylazine and placed on a heating pad. Ag/AgCl wire electrodes were bridged with capillary tubes filled with Hanks balanced salt solution. The active electrode was placed in contact with the corneal surface and referenced to a second electrode placed within the orbit. The dc-ERG signal was amplified (dc-100 Hz), digitized, and stored offline. The duration of full-field flash stimuli was controlled using a mechanical shutter and flash luminance was controlled with neutral density filters. EOGs were recorded using subdermal platinum needle electrodes placed near the eye. In response to a 5-min light exposure, the dc-ERG of LE and SD rats included a distinct b-wave, after potential, c-wave, fast oscillation, and a slow potential of positive polarity the characteristics of which are consistent with a light peak.

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Müller, Philipp L., Tim Treis, Alexandru Odainic, Maximilian Pfau, Philipp Herrmann, Adnan Tufail, and Frank G. Holz. "Prediction of Function in ABCA4-Related Retinopathy Using Ensemble Machine Learning." Journal of Clinical Medicine 9, no. 8 (July 29, 2020): 2428. http://dx.doi.org/10.3390/jcm9082428.

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Full-field electroretinogram (ERG) and best corrected visual acuity (BCVA) measures have been shown to have prognostic value for recessive Stargardt disease (also called “ABCA4-related retinopathy”). These functional tests may serve as a performance-outcome-measure (PerfO) in emerging interventional clinical trials, but utility is limited by variability and patient burden. To address these limitations, an ensemble machine-learning-based approach was evaluated to differentiate patients from controls, and predict disease categories depending on ERG (‘inferred ERG’) and visual impairment (‘inferred visual impairment’) as well as BCVA values (‘inferred BCVA’) based on microstructural imaging (utilizing spectral-domain optical coherence tomography) and patient data. The accuracy for ‘inferred ERG’ and ‘inferred visual impairment’ was up to 99.53 ± 1.02%. Prediction of BCVA values (‘inferred BCVA’) achieved a precision of ±0.3LogMAR in up to 85.31% of eyes. Analysis of the permutation importance revealed that foveal status was the most important feature for BCVA prediction, while the thickness of outer nuclear layer and photoreceptor inner and outer segments as well as age of onset highly ranked for all predictions. ‘Inferred ERG’, ‘inferred visual impairment’, and ‘inferred BCVA’, herein, represent accurate estimates of differential functional effects of retinal microstructure, and offer quasi-functional parameters with the potential for a refined patient assessment, and investigation of potential future treatment effects or disease progression.

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Neroev, Vladimir V., Marina V. Zueva, Natalia V. Neroeva, Denis V. Fadeev, Irina V. Tsapenko, Tatiana D. Okhotsimskaya, and Vladislav I. Kotelin. "Changes in Functional Activity of Rabbit’s Retina During Flicker Photostimulation with Scale-free Dynamics." International Journal of Clinical Medicine and Bioengineering 2, no. 2 (June 30, 2022): 1–19. http://dx.doi.org/10.35745/ijcmb2022v02.02.0001.

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Neuroplasticity-based stimulation therapy assists in restoring the visual system in neurodegenerative disorders. Scale-free fluctuations peculiar to healthy physiological rhythms disappear as the disease progresses. Fractal visual stimuli positively influence CNS plasticity and increase the efficiency of visual rehabilitation. To determine the effect of a lengthy course of fractal photostimulation (FS) on the electroretinogram (ERG) in healthy rabbits, a device for FS was created. For twelve healthy rabbits, 20-minute FS sessions were conducted once a day from 9 to 11 a.m., five times a week. Before and after 1, 4, and 12 weeks of FS, full-field ERGs, flicker ERGs, and the pattern-ERGs were registered. The observed positive impact of FS consisted of shortening peak latency of the maximal scotopic ERG b-wave and a significant increase in the amplitude of the cone ERG a- and b-waves and low-frequency flicker ERGs (p<0.05). For the first time, we describe the effect of FS on the ERG. The long-term FS does not impair retinal activity and can be safely used in the clinic. The dynamics of the positive influence of FS on retinal activity argue that the duration of the FS course of 1 to 4 weeks is optimal for subsequent studies.

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ALEXANDER, KENNETH R., MICHAEL W. LEVINE, and BOAZ J. SUPER. "Characteristics of period doubling in the human cone flicker electroretinogram." Visual Neuroscience 22, no. 6 (November 2005): 817–24. http://dx.doi.org/10.1017/s0952523805226111.

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Electroretinogram (ERG) responses of the cone system to a flickering stimulus can exhibit a cyclic variation in amplitude. This phenomenon of synchronous period doubling has been attributed to a nonlinear feedback mechanism within the retina that alters response gain. The aim of the present study was to investigate intersubject variability in period doubling in the ERG of the human cone system, and to assess the implications of this variability for signal processing within the retina. Period doubling was examined in a group of 12 visually normal subjects, using sinusoidal full-field flicker and harmonic analysis of the ERG waveforms. For all subjects, the ERG responses to 32-Hz flicker (a frequency commonly used clinically) were characterized by a harmonic component at the stimulus frequency and at higher harmonics that were integral multiples of the stimulus frequency, as expected. In addition, six of the subjects showed period doubling at 32 Hz, characterized by harmonic components at integer multiples of a frequency that was half the stimulus frequency (the subharmonic). However, the subharmonic itself did not exceed the noise level. These findings suggest that the subharmonic is generated prior to or at the site that produces the nonlinear higher harmonics of the ERG response, and that a subsequent band-pass filter attenuates this subharmonic. Examination of harmonic components of the subjects' ERG waveforms at other stimulus frequencies, as well as a cycle-by-cycle analysis of the ERG waveforms, suggested that individual differences in period doubling may be due to intersubject variation in the strength of the hypothesized feedback signal and/or the time constant of its decay.

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Zolnikova, I. V., V. V. Kadyshev, A. V. Marakhonov, S. I. Kutsev, and R. A. Zinchenko. "Аutosomal Dominant Oculodental-Digital Dysplasia with Mutation in Gene GJA1 (Clinical Case)." Ophthalmology in Russia 18, no. 1 (April 4, 2021): 157–64. http://dx.doi.org/10.18008/1816-5095-2021-1-157-164.

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The purpose: to describe clinical cases of oculodental-digital dysplasia (ODDD, OMIM #164200) with mutation in GJA1 (OMIM 121014) with molecular genetic verification of the diagnosis.Methods. The article describes the clinical case of oculodental-digital dysplasia in a 51 years old patient. Patient underwent full ophthalmic examination including autorefractometry, visual acuity testing with full correction, tonometry, biomicroscopy, fundus examination and photo as well as kinetic perimetry, autofluorescence and optical coherence tomography (OCT) of macula and optic disk were performed. Electrophysiological examination included Visual Evoked Potentials (VEP) to flash and pattern stimulation, ISCEV standard electroretinograms (ERG) and macular ERG. For the verification of the diagnosis and pathologic gene molecular genetic examination was performed with family anamnesis previously attained.Results. The patient was complaining the deterioration of vision, hearing loss and the sense of smell. Visual deterioration was associated with nyctalopia. Natural history revealed glaucoma 2а which was diagnosed when he was 48 years old. Best corrected visual acuity was 1,0. Peripheral visual field defects were revealed bilaterally. High visual acuity correlated with normal foveal structure on OCTs the retinal nerve fiber layer (RNFL) was thinner than normal in temporal half; deep excavation was visualized in both eyes. Normal MERG and bilateral decrease of scotopic, maximal full-field ERG was recorded which correlated with nyctalopia, as well as subnormal photopic responses indicating cone system involvement. The genetics revealed characteristic features of the face: a small nose with hypoplasia of the wings of the nose, unfolded nostrils and a wide bridge of the nose (pseudohypertelorism). On right-wing the ear sink was detected 2 antitraguses. Changes fingers upper extremities — operated syndactyly IV and V on the background of brachydactyly of the fingers. On the legs on both sides — syndactyly III–IV. 10 years the sense of smell has been dereriorated. In the study of DNA in proband in direct Sanger sequencing of all exons 1–2 and regions of exon-intron compounds of gene GJA1, was found the pathogenic variant in second exon c.412G>A (p.Gly138Ser) in heterozygous state. Was established autosomal dominant type of disease.Conclusion. We are the first to describe rod-cone dystrophy in oculodental-digital dysplasia.

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GREEN, DANIEL G., and NATALIA V. KAPOUSTA-BRUNEAU. "A dissection of the electroretinogram from the isolated rat retina with microelectrodes and drugs." Visual Neuroscience 16, no. 4 (July 1999): 727–41. http://dx.doi.org/10.1017/s0952523899164125.

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The origins of the a- and b-wave of the ERG were studied using simultaneous recordings made across the receptor layer and the full thickness of a piece of isolated albino rat retina. An inwardly directed current flowing across the rod outer segments was eliminated from the recording when postsynaptic activity was blocked with cobalt or when current source density measurements were made along the length of the outer segments. Rod photovoltages were inferred by removing extraneous field potentials from the recordings made across the photoreceptor layer. The spatial properties of the photovoltage indicates the responses came from an area about 100 μm in diameter. The glutamate analog, APB, which blocks depolarizing bipolar cells, eliminated the b-wave but left the a-wave unaffected. The ERG component due to depolarizing bipolar cells was inferred by subtracting recordings obtained before and after APB. After treatment with APB a slow component remained. This component was completely blocked by barium (200 μM), which blocks potassium channels on Müller cells. Barium had virtually no effect on low-intensity photovoltages but did affect the amplitude and shape of the saturated responses. Barium increased the amplitude of the component of the ERG which underlies the b-wave. It was concluded that the depolarizing bipolar cells directly generate the b-wave of the ERG.

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Journal articles on the topic 'Full-field ERG'

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