To compare the baseline signal between two conditions used to generate the photopic negative response (PhNR) of the full-field electroretinogram (ERG): red flash on a blue background (RoB) and white flash on a white background (LA3). The secondary purpose is to identify how the level of pre-stimulus signal affects obtaining an unambiguous PhNR component. A retrospective chart review was conducted on four cohorts of patients undergoing routine ERG testing. In each group, LA3 was recorded the same way while RoB was generated differently using various luminances of red and blue light. The background bioelectrical activity 30 ms before the flash was extracted, and the root mean square (RMS) of the signal was calculated and compared between RoB and LA3 using Wilcoxon test. Pre-stimulus noise was significantly higher under RoB stimulation versus LA3 in all four conditions for both right and left eyes (ratio RoB/LA3 RMS 1.70 and 1.57 respectively, p < 0.033). There was also no significant difference between the RMS of either LA3 or RoB across protocols, indicating that the baseline noise across cohorts were comparable. Additionally, pre-stimulus noise was higher in signals where PhNR was not clearly identifiable as an ERG component versus signals with the presence of unambiguous PhNR component under RoB in all four groups for both eyes (p < 0.05), whereas the difference under LA3 was less pronounced. Our study suggests that LA3 produces less background bioelectrical activity, likely due to decreased facial muscle activity. As it seems that the pre-stimulus signal level affects PhNR recordability, LA3 may also produce a better-quality signal compared to RoB. Therefore, until conditions for a comparable bioelectrical activity under RoB are established, we believe that LA3 should be considered at least as a supplementary method to evaluate retinal ganglion cell function by ERG.

This review aims to consolidate the available information on use of electroretinography as a diagnostic tool in psychiatry. The electroretinogram (ERG) has been found to have diagnostic utility in cocaine withdrawal (reduced light-adapted b-wave response), major depressive disorder (reduced contrast gain in pattern ERG), and schizophrenia (reduced a- and b-wave amplitudes). This review examines these findings as well as the applicability of ERG to substance use disorder, Alzheimer’s disease, autism spectrum disorder, panic disorder, eating disorders, attention deficit hyperactivity disorder, and medication use. While there have been promising results, current research suffers from a lack of specificity. Further research that quantifies anomalies in ERG present in psychiatric illness is needed.

The objective of the study was to examine whether a nutritional antioxidant supplementation could improve visual function in healthy dogs as measured by electroretinography (ERG) and autorefraction. A total of twelve Beagles, 6 to 8 years of age, with normal eyes upon indirect ophthalmoscopy and slit lamp biomicroscopy, were age and sex matched and randomly assigned to receive a feeding regimen for 6 months with or without a daily antioxidant supplementation. Portable, mini-Ganzfeld ERG and a Welch Allyn hand-held autorefractor were used to test retinal response and refractive error in the dogs at baseline and at the end of the supplementation period. All ERG a-wave amplitudes obtained were increased in the treatment group compared with those of dogs in the control group, with significant improvements in the scotopic high and photopic single flash cone ERG responses (P < 0·05 for both). For the b-wave amplitudes, all responses were similarly increased, with significant improvements in responses for the scotopic high light intensity stimulation (P < 0·05), and for photopic single flash cone and 30 Hz flicker (P < 0·01 for both) recordings. Change in refractive error was significantly less in the treatment group compared with that of the control group during the 6-month study (P < 0·05). Compared with the control group, the antioxidant-supplemented group showed improvement to varying degrees for retinal function and significantly less decline in refractive error. Dogs, like humans, experience retinal and lens functional decline with age. Antioxidant supplementation as demonstrated may be beneficial and effective in the long-term preservation and improvement of various functions of the canine eye.

Lutein and zeaxanthin are lipid-soluble antioxidants found within the macula region of the retina. Links have been suggested between increased levels of these carotenoids and reduced risk for age-related macular disease (ARMD). Therefore, the effect of lutein-based supplementation on retinal and visual function in people with early stages of ARMD (age-related maculopathy, ARM) was assessed using multi-focal electroretinography (mfERG), contrast sensitivity and distance visual acuity. A total of fourteen participants were randomly allocated to either receive a lutein-based oral supplement (treated group) or no supplement (non-treated group). There were eight participants aged between 56 and 81 years (65·50 (sd 9·27) years) in the treated group and six participants aged between 61 and 83 years (69·67 (sd 7·52) years) in the non-treated group. Sample sizes provided 80 % power at the 5 % significance level. Participants attended for three visits (0, 20 and 40 weeks). At 60 weeks, the treated group attended a fourth visit following 20 weeks of supplement withdrawal. No changes were seen between the treated and non-treated groups during supplementation. Although not clinically significant, mfERG ring 3 N2 latency (P= 0·041) and ring 4 P1 latency (P= 0·016) increased, and a trend for reduction of mfERG amplitudes was observed in rings 1, 3 and 4 on supplement withdrawal. The statistically significant increase in mfERG latencies and the trend for reduced mfERG amplitudes on withdrawal are encouraging and may suggest a potentially beneficial effect of lutein-based supplementation in ARM-affected eyes.

Replacement of retinal pigment epithelium (RPE) cells by transplantation is a potential treatment for some retinal degenerations. Here, we used a combination of invasive and noninvasive methods to characterize the structural and functional consequences of subretinal injection of RPE cells. Pigmented cells from primary cultures were injected into albino mice. Recovery was monitored over 8 weeks by fundus imaging, spectral domain optical coherence tomography (sdOCT), histology, and electroretinography (ERG). sdOCT showed that retinal reattachment was nearly complete by 1 week. ERG response amplitudes were reduced after injection, with cone-mediated function then recovering better than rod function. Photoreceptor cell loss was evident by sdOCT and histology, near the site of injection, and is likely to have been the main cause of incomplete recovery. With microscopy, injected cells were identified by the presence of apical melanosomes. They either established contact with Bruch’s membrane, and thus became part of the RPE monolayer, or were located on the apical surface of the host’s cells, resulting in apposition of the basal surface of the injected cell with the apical surface of the host cell and the formation of a series of desmosomal junctions. RPE cell density was not increased, indicating that the incorporation of an injected cell into the RPE monolayer was concomitant with the loss of a host cell. The transplanted and remaining host cells contained large vacuoles of ingested debris as well as lipofuscin-like granules, suggesting that they had scavenged the excess injected and host cells, and were stressed by the high digestive load. Therefore, although significant functional and structural recovery was observed, the consequences of this digestive stress may be a concern for longer-term health, especially where RPE cell transplantation is used to treat diseases that include lipofuscin accumulation as part of their pathology.

Congenital achromatopsia is a stationary retinal disorder with autosomal recessive inheritance. It is characterized by significant attenuation of cone-photoreceptor function. Symptoms include photophobia, nystagmus, and poor visual acuity from birth. Unlike in cone or cone–rod dystrophies, the retinal fundus usually appears normal. Here we describe two siblings with congenital achromatopsia, who exhibit different ophthalmic phenotypes. History was taken, and ophthalmic examinations were performed in a 7-year-old girl and her 5-year-old brother, who were referred to our department because of poor visual acuity. Two of their grandparents were brother and sister, suggesting an autosomal recessive transmission in inheritance. They have been followed for more than 13 years since the initial evaluation. Symptoms, visual acuity, and kinetic visual field were very similar to each other, consistent with findings of typical congenital achromatopsia. However, color-vision tests suggested that the brother had residual color discrimination, but the sister did not. The siblings had different full-field electroretinographic and spectral-sensitivity findings: residual cone functions were detected in only the brother, in agreement with his residual color vision. They also had different findings of retinal fundi and ocular refractions: the sister had bilaterally atrophic-appearing macular lesions and myopic errors. In contrast, the brother remains hyperopia and has exhibited no specific retinal findings until age 18 years. The causes why both complete and incomplete achromats occur in the siblings are uncertain but might be caused by modifying effects of sex-related genes or by environmental factors influencing certain gene regulations in cone photoreceptors.

Objectives: To conduct a systematic review of the evidence for the effectiveness of five visual electrodiagnostic tests to inform the Medical Services Advisory Committee (MSAC) of the Department of Health and Ageing (Australia) in its decision in allocating public funding for new technologies.

Methods: We searched the biomedical literature to identify English-language articles published from 1966 to September 2000. We assessed validity of methodology of included studies against the following criteria: investigators (i) compared test with an appropriate reference test; (ii) tested an appropriate spectrum of patients; (iii) masked assessment of study and reference tests; (iv) measured the study test independently of clinical information; and (v) measured the reference test before any interventions.

Results: Sixty-one articles met inclusion criteria for critical appraisal: nineteen were cross-sectional studies that compared a study test with another test, thirty-four were case-control studies that compared a test in a group of patients with an eye disease to a group of subjects without eye disease, and eight studies were case series. None of the included studies met all of the validity criteria. Only four studies provided enough information to calculate diagnostic characteristics but were flawed due to inclusion of patients already diagnosed with disease or lack of an appropriate reference test and, thus, overestimated test accuracy.

Conclusions: Identified studies did not provide sufficient valid evidence of the clinical value of the five visual tests in diagnosing diseases of the retina or optic nerve. Thus, MSAC recommended that the tests not be supported by public funding.

Kang Derwent and Linsenmeier (2000) reported that the a- and b-waves of the cat electroretinogram (ERG) are resistant to hypoxemia, at least for PaO2 above 40 mm Hg. The a-wave may be resistant because the photoreceptor can increase glycolysis during hypoxemia. This hypothesis was tested by making the animal hypoglycemic, which should minimize the ability of the photoreceptor to switch to glycolysis. The ERG of dark-adapted anesthetized cats was recorded between an Ag/AgCl electrode in the vitreous humor and a reference electrode near the eye. Responses to bright flashes of diffuse white light were recorded at 3-min intervals during hypoxic episodes at three levels of blood glucose. The moderate hypoglycemia (50 to 70 mg/dl) had a relatively small effect on the a-wave amplitude. Furthermore, the a-wave amplitude increased transiently by 16 ± 7% within 30–40 min of the start of severe hypoglycemia (20 to 40 mg/dl), before recovering to near normal. Severe hypoglycemia alone decreased the b-wave amplitude by 15 ± 13%. Combined hypoxemia and hypoglycemia decreased the b-wave amplitude more than the a-wave amplitude. At all levels of blood glucose, b-wave decreases began at a higher PaO2 than the a-wave changes. For both the a- and b-waves, hypoxemic effects began at higher PaO2 when the animal was hypoglycemic. The increased sensitivity to hypoxemia during severe hypoglycemia suggests that a switch from oxidative to glycolytic metabolism ordinarily protects the retina from moderate hypoxemia. Because the a- and b-waves were affected to different degrees and at different PaO2s, it is unlikely that inner retinal changes are caused completely by changes in the photoreceptor.