OBJECTIVE: The aim of this exploratory study is to investigate the role of S-cones in oscillatory potentials (OPs) generation by individuals with blue-cone monochromacy (BCM), retaining S-cones, and achromatopsia (ACHM), lacking cone functions.
METHODS: This retrospective study analyzed data from 39 ACHM patients, 20 BCM patients, and 26 controls. Central foveal thickness was obtained using spectral-domain optical coherence tomography, while amplitude and implicit time (IT) of a- and b-waves were extracted from the ISCEV Standard dark-adapted 3 cd.s.m-2 full-field ERG (ffERG). Time-frequency analysis of the same measurement enabled the extraction of OPs, providing insights into the dynamic characteristics of the recorded signal.
RESULTS: Both ACHM and BCM groups showed a significant reduction (p < .00001) of a- and b-wave amplitudes and ITs as well as the power of the OPs compared to the control groups. The comparison between ACHM and BCM didn\'t show any statistically significant differences in the electrophysiological parameters. The analysis of covariance revealed significantly reduced central foveal thickness in the BCM group compared to ACHM and controls (p < .00001), and in ACHM compared to controls (p < .00001), after age correction and Tukey post-hoc analysis.
CONCLUSIONS: S-cones do not significantly influence OPs, and the decline in OPs\' power is not solely due to a reduced a-wave. This suggests a complex non-linear network influenced by photoreceptor inputs. Morphological changes don\'t correlate directly with functional alterations, prompting further exploration of OPs\' function and physiological role.

BACKGROUND: Diabetic retinopathy (DR) is a neurodegenerative disease of the retina. The aim of our study was to analyze latency changes in a full-field electroretinogram (ERG) in patients with type 2 diabetes.
METHODS: This prospective study included 15 diabetic patients without DR, 16 diabetic patients with non-proliferative DR, 14 patients with pre-proliferative DR, 15 patients with proliferative DR, and 14 age-matched controls. All the participants underwent ophthalmologic examination and full-field ERGs. The ERGs were recorded with the Metrovision MonPackOne system. The latencies were analyzed for \"a\"- and \"b\"-waves in the dark-adapted (DA) 0.01 ERG, DA 3.0 ERG, DA oscillatory potentials, light-adapted (LA) 3.0 ERG, and 30 Hz flicker ERG.
RESULTS: The delayed responses of healthy subjects compared to diabetic patients without DR were the DA oscillatory potentials (25.45 ± 1.04 ms vs. 26.15 ± 0.96 ms, p = 0.027). When comparing diabetic patients without DR and with non-proliferative DR, we did not obtain statistically significant delays. Significant delays in the DA 0.01 \"b\"-wave (61.91 ± 5.52 ms vs. 66.36 ± 8.12 ms, p = 0.029), DA 3.0 \"b\"-wave (41.01 ± 2.50 ms vs. 44.16 ± 3.78 ms, p = 0.035), and LA 3.0 \"a\"-wave (16.21 ± 0.91 ms vs. 16.99 ± 1.16 ms, p = 0.045) were found between non-proliferative DR and pre-proliferative DR. When comparing the groups of patients with pre-proliferative DR and proliferative DR, the LA 3.0 ERG \"b\"-wave (32. 63 ± 2.53 ms vs. 36.19 ± 3.21 ms, p < 0.0001), LA 30 Hz flicker ERG \"a\"-wave (19.56 ± 3.59 vs. 21.75 ± 4.74 ms, p= 0.025), and \"b\"-wave (32.23 ± 4.02 vs. 36.68 ± 3.48 ms, p = 0.017) were delayed.
CONCLUSIONS: the electrophysiological findings from our study indicate that there is a substantial dysfunction of the neural retina in all stages of DR.

Electroretinogram (ERG) is a sensitive and useful tool for the measurement of the retina\'s electrical response to flash stimuli. It provides a functional evaluation of the photoreceptors and downstream associated retinal cells. Similar to those conducted on humans, mouse ERGs include the amplitudes of a- and b-waves as well as the implicit time from those ERGs. Applications of ERGs include identification of retinal phenotypes, measurement of retinal function (at one and various time points), and evaluation of treatment efficacy. However, there are some differences between the manifestation of disease in patients as compared to mouse models that should be taken into consideration when implementing mouse ERGs. Herein, this chapter will introduce how to perform and obtain mouse ERGs.

Electroretinogram (ERG) captures the electrical responses of photoreceptors, the summation of action potentials from all neurons in the retina elicited by illumination. ERG testing is an incredibly useful tool in obtaining more specific information regarding a retinal dystrophy. Specifically, ERGs are typically used to test photoreceptors and inner retinal function in humans and animals, to diagnose retinal dystrophies, and to monitor disease progression. In this chapter, we will introduce the components of ERGs and the standard ERG protocols for clinical examination. We will also introduce the various specialized ERG tests, which can help to differentiate retinitis pigmentosa (RP) from other retinal disorders. Lastly, we will elaborate on how to use ERGs to predict visual prognosis in RP.

To describe vitamin A deficiency using multimodal functional visual assessments and imaging.
A 50-year-old female with past medical history significant for Roux-en-Y gastric bypass surgery complained of nyctalopia and \"yellowing\" of vision.
Vitamin A levels were noted to be < 0.06 mg/L (normal 0.3-0.12 mg/L). Fundus examination was notable for peripheral yellow punctate lesions, superior arcuate defects on HVF 30-2 testing, an indistinct ellipsoid zone on SD-OCT, and absent rod responses and severely reduced amplitudes for the cone photoreceptors on full-field ERG. These findings resolved with initiation of parenteral vitamin A supplementation.
This report documents an example of vitamin A deficiency in the developed world. We aim to provide a comprehensive description of clinical examination and multimodal imaging findings before and after vitamin supplementation for vitamin A deficiency.

OBJECTIVE: To compare retinal function assessed by full-field electroretinography (ffERG) and multifocal electroretinography (mfERG) in diabetes without retinopathy, diabetes with moderate non-proliferative diabetic retinopathy (NPDR) and in the absence of diabetes.
METHODS: Scotopic and photopic ffERG and mfERG was made in non-fasting volunteers, including 26 diabetic participants without retinopathy, 22 diabetic participants with moderate NPDR and 22 participants without diabetes using full International Society for Clinical Electrophysiology of Vision protocols.
RESULTS: Of the ffERG responses, significant deviation (p ≤ 0.05, corrected for multiple sampling and other relevant confounders) from the non-diabetic participants was seen in the diabetic participants only for the OP1-OP3 oscillatory amplitudes and the OP2 implicit time. This finding was independent of whether retinopathy was present or not. For the mfERG, minor amplitude or implicit time deviations were found for a small number of rings (R2, R4 and R5). Receiver of operating characteristic analysis showed that the single most prominent abnormality of the ffERG in diabetes, regardless of whether retinopathy was present or not, was the OP2 implicit time (area under the curve ≥ 0.80).
CONCLUSIONS: This bi-modal study of electroretinographic characteristics found that the most prominent anomaly associated with diabetes was a prolongation of the implicit time of the OP2 of the scotopic ffERG, while the most prominent added effect of non-proliferative diabetic retinopathy was a further prolongation of the OP2 implicit time. Although the variation in ERG characteristics is far too large for diagnostic purposes, the close association of the oscillatory potentials with the amacrine cells of the retina indicate that their function is particularly sensitive to diabetes.

The full-field electroretinogram (ERG) is a mass electrophysiological response to diffuse flashes of light and is used widely to assess generalized retinal function. This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV), presents an updated and revised ISCEV Standard for clinical ERG testing. Minimum protocols for basic ERG stimuli, recording methods and reporting are specified, to promote consistency of methods for diagnosis, monitoring and inter-laboratory comparisons, while also responding to evolving clinical practices and technology. The main changes in this updated ISCEV Standard for clinical ERGs include specifying that ERGs may meet the Standard without mydriasis, providing stimuli adequately compensate for non-dilated pupils. There is more detail about analysis of dark-adapted oscillatory potentials (OPs) and the document format has been updated and supplementary content reduced. There is a more detailed review of the origins of the major ERG components. Several tests previously tabulated as additional ERG protocols are now cited as published ISCEV extended protocols. A non-standard abbreviated ERG protocol is described, for use when patient age, compliance or other circumstances preclude ISCEV Standard ERG testing.

To investigate the magnitude and time course of pseudorandom ffERG during light adaptation.
Ten healthy subjects (26 ± 10.1 years) underwent 20 min of dark adaptation, and then the ffERG was evoked by pseudorandom flash sequences (4 ms per flash, 3 cd.s/m2) driven by m-sequences (210-1 stimulus steps) using Veris Science software and a Ganzfeld dome over a constant field of light adaptation (30 cd/m2). The base period of the m-sequence was 50 ms. Each stimulation sequence lasting 40 s was repeated at 0, 5, 10, 15 and 20 min of light adaptation. Relative amplitude and latency (corrected by values found at 0 min) of the three components (N1, P1, and N2) of first-order (K1) and first slice of the second-order (K2.1) kernel at 5 time points were evaluated. An exponential model was fitted to the mean amplitude and latency data as a function of the light adaptation duration to estimate the time course (τ) of the light adaptation for each component. Repeated one-way ANOVA followed by Tukey post-test was applied to the amplitude and latency data, considering significant values of p < 0.05.
Regarding the K1 ffERG, N1 K1, P1 K1, and N2 K1 presented an amplitude increase as a function of the light adaptation (N1 K1 τ value = 2.66 min ± 4.2; P1 K1 τ value = 2.69 min ± 2.10; and N2 K1 τ value = 3.49 min ± 2.96). P1 K1 and N2 K1 implicit time changed as a function of the light adaptation duration (P1 K1 τ value = 3.61 min ± 5.2; N2 K1 τ value = 3.25 min ± 4.8). N1 K1 had small implicit time changes during the light adaptation. All the K2,1 components also had nonsignificant changes in amplitude and implicit time during the light adaptation.
Pseudorandom ffERGs showed different mechanisms of adaptation to retinal light. Our results suggest that K1 ffERG is generated by retinal mechanisms with intermediate- to long-term light adaptation, while K2.1 ffERG is generated by retinal mechanism with fast light adaptation course.

To describe a patient with combined central serous chorioretinopathy and achromatopsia.
Clinical examination, enhanced depth imaging- optical coherence tomography, fundus autofluorescence, fluorescein angiography and electroretinography were used to study a 33-year-old female presented with the complaint of poor vision since childhood in both eyes, which worsened in the left eye (LE) recently.
In slit-lamp examination, there was a macular elevation in the LE and macular pigmentary change as well as optic disk pallor in both eyes. Enhanced depth imaging optical coherence tomography revealed central inner/outer segment (IS/OS) disruptions, subretinal fluid and thick choroid. Accessory tests included the full-field ERG with severe reduced photopic response (with relatively normal scotopic responses) and fluorescein angiography (FA), which found distinct leakage points in OD and barely visible hyperfluorescent spots in OS. Based on the history of nystagmus, lifelong stable poor vision, loss of foveal cone thickness with IS/OS disruption and severe reduced photopic response with relatively normal scotopic responses, we determined that the diagnosis was most consistent with achromatopsia (ACHM). On the other hand, OCT and FA findings show the simultaneous occurrence of pachychoroid-related central serous chorioretinopathy in this patient.
This case highlights a case of CSC and ACHM.

To evaluate the physiology of the macular and whole retina after intravitreal aflibercept (IVAs) injections in patients with macular edema associated with a central retinal vein occlusion (CRVO) by electroretinography (ERG).
We studied 20 eyes of 20 patients with non-ischemic CRVO (72.0 ± 9.2 years). All patients were treated with monthly injections of IVA for the initial 3 months and then treated by the treat-and-extend (TAE) regimen for 12 months. The best-corrected visual acuity (BCVA), optical coherence tomographic images, focal macular ERGs (fmERGs), and full-field ERGs recorded before and after the treatment were compared. The fmERGs were elicited by a 15° white stimulus spot centered on the fovea. The full-field ERGs were recorded by a protocol recommended by International Society for Clinical Electrophysiology of Vision. The amplitudes and implicit times determined before and after the IVA were compared.
The foveal thickness was significantly reduced accompanied by improvement of the BCVA after the treatments, and the improvements were maintained for at least 12 months. The amplitudes and implicit times of the fmERGs improved continuously for the 12 months. On the other hand, the reduced amplitudes of the full-field ERG, summed oscillatory potentials, and the photopic negative responses remained unchanged for the 12-month period. However, the implicit times of the maximum and cone responses were significantly shortened after the IVA.
IVA injections by the TAE regimen led to a continuous improvement of the macular function in patients with ME associated with a CRVO. However, the function of the whole retina changed differently than the macula after the treatment.