Multifocal Electroretinogram Research Articles

Electrophysiological findings in extensive macular atrophy with pseudodrusen.

To present electroretinogram findings in extensive macular atrophy with pseudodrusen (EMAP) and describe associated systemic factors. Retrospective case series. Data on medical history, visual symptoms, multimodal imaging findings, and visual field were collected from the medical records of patients with extensive macular atrophy with pseudodrusen who attended a visual electrophysiology laboratory. Electrophysiological tests, including full-field electroretinogram, multifocal electroretinogram and photopic negative response, were performed. Eighteen patients (10 [56%] females, age 49-66years) were included. Of these, 17 (94%) had a history of rheumatic fever in childhood and/or adolescence, 7 (39%) had cardiovascular disease, 4 (22%) had autoimmune disease, and 10 (56%) had inflammatory conditions. The primary visual complaints were nyctalopia (95%), followed by visual field loss (67%) and dyschromatopsia (67%). The key retinal findings included retinal pigmented epithelium atrophy in the macular region and subretinal drusenoid deposits. Regarding electrophysiological results, 100% of patients had abnormalities on multifocal electroretinogram, 94% displayed alterations in photopic negative response, and 78% showed changes in the full-field electroretinogram. In this cohort, electrophysiologic evaluation demonstrated diffuse retinal dysfunction affecting all layers of the retina in patients with EMAP. The disease is associated with immune-mediated systemic conditions, chiefly rheumatic fever.

Decreased perifoveal ganglion cell complex thickness - a first sign for macular damage in patients using hydroxychloroquine.

Aim: To examine ganglion cell complex (GCC) thickness detected by optical coherence tomography (OCT) in patients using hydroxychloroquine (HCQ), without any structural and functional macular changes to evaluate the initial symptoms of macular toxicity for early diagnosis before clinical evaluation. Methods: Eighty eyes of forty patients (Group 1) and forty eyes of twenty healthy volunteer persons (Group 2) were included in the study. Detailed ophthalmologic and mydriatic fundus examination were applied to all patients and volunteers (controls). Spectral domain OCT, visual field (VF) and color vision test were performed. Measurements of macula thickness, GCC thickness (involving nerve fiber layer, ganglion cell layer and inner plexiform layer) and peripapillary retinal nerve fiber layer (RNFL) were performed with OCT. Patients with retinal pigment epithelial changes, VF paracentral scotoma and defected color vision were excluded from the planned study. Results: Perifoveal GCC layer thickness in all quadrants was significantly thinner in group 1 compared to group 2 (p=0.017, p=0.001, p=0.019, p=0.001). The mean global inferior hemifield and nasal quadrant RNFL thickness were lower than in the control groups (p=0,012, p=0,009, p=0,005, respectively). Conclusion: Changes in the thickness of nerve fiber layer and ganglion cell layer detected by optical coherence tomography can be thought to be used as a diagnostic aid for the early diagnosis of hydroxychloroquine-toxic maculopathy Abbreviations: GCC = Ganglion cell complex, OCT = Optical coherence tomography, HCQ = Hydroxychloroquine, BCVA = Best-corrected visual acuity, IOP = Intraocular pressure, VF = Visual field, RNFL = Retinal nerve fiber layer, SD OCT = Spectral-domain optical coherence tomography, mfERG = Multifocal electroretinogram, FAF = Fundus autofluorescence, IS/ OS = Inner segment-outer segment junction, SITA = Swedish Interactive Threshold Algorithm, RA = Rheumatoid arthritis, SLE = Systemic lupus erythematosus, SS = Sjogren syndrome.

Evaluation of retinal structure and function in prediabetes

PurposeAlterations in retinal structure and function have been well documented in type 2 diabetes (T2DM). However, few studies have evaluated the eye in prediabetes (preDM), a precursor to T2DM. It is unknown which retinal deficits, if any, occur before T2DM diagnosis. This study evaluates retinal structure via optical coherence tomography (OCT) and retinal function via multifocal electroretinogram (mfERG) N1 and P1 in those with PreDM. The goal is to evaluate associations between structure and function across glucose dysfunction. Methods85 subjects (aged 28–69yrs) were tested with VERIS mfERG and Heidelberg Spectralis OCT. Demographic and health information was collected. Subjects were grouped by HbA1c: 33 controls (HbA1c <5.7%), 31 with preDM (HbA1c 5.7–6.4%), and 21 with T2DM (HbA1c >6.4% at the time of testing or diagnosed by physician) and mild or no retinopathy. mfERG N1 and P1 latency and amplitude were measured for the right eye in the foveal hexagon (central 2.4°). Average macular thickness was also measured over the central 3.3°. Groups were compared with ANOVA and corrected t-tests. Models of these associations with diabetes diagnosis (in groups above) were created with backward multivariate regression. ResultsThe T2DM group was exceptionally well-controlled with an HbA1c of 7.0% ± 0.68 but also had elevated systolic blood pressure compared to other groups (P<0.01). The age of the control group was younger (P<0.01), so other testing was age controlled. There was a borderline but statistically significant difference in P1 between the control group and both the preDM and T2DM groups after Bonferroni corrections (P<0.03). There was also a difference in N1 latency between the control and other groups (P<0.001). A multivariate model demonstrated a significant relationship between T2DM/PreDM diagnosis and delayed N1 latency, reduced foveal thickness, and age. ConclusionsStructure and function together can provide an associative model of preDM or T2DM changes for patients. Based on this multivariate model, N1 is strongly associated with preDM and T2DM. N1 findings and decreasing foveal thickness are additive and can together inform ocular health related to preDM. Future longitudinal studies are needed to understand changes in function and structure in preDM and T2DM.

Dual-focus contact lenses for myopia control modify central retinal electrophysiology in humans.

Dual-focus contact lenses create two focal planes, one providing a clear retinal image while the other imposes myopic defocus on the retina to slow myopia progression. This study used global-flash multifocal electroretinogram (gmfERG) response amplitudes to compare central versus peripheral retinal responses under dual-focus conditions and to assess the optimal degree of myopic defocus compared with a single-vision control lens. Twenty participants each underwent three gmfERG trials, wearing a spectacle correction over dual-focus contact lenses with plano central power and peripheral secondary focal powers of either +2.00D, +4.00D or a plano single-vision lens. We compared amplitudes and latencies of the gmfERG direct and induced components (DC and IC) within participants, between the three different contact lens powers and at different retinal eccentricities (gmfERG ring). We observed significant differences in the gmfERG responses between the single-vision and dual-focus contact lenses. Overall, DC amplitudes peaked between zero and +2.00D secondary power, while IC amplitudes were maximal between +2.00D and +4.00D. Compared with the single-vision control, the greatest increase in DC and IC amplitudes while wearing dual-focus lenses occurred within the central 10° of the retina. There was no interaction effect between gmfERG ring (eccentricity) and secondary power, and no difference in the latency of the gmfERG responses between different powers. We found that dual-focus contact lenses with a +2.00D secondary power are close to that expected to induce the greatest increase in gmfERG responses relative to a single-vision lens. Dual-focus lenses produced the highest DC and IC response amplitudes relative to a single-vision lens in the central 10° of the retina. This suggests that dual-focus contact lenses slow myopia progression by modifying central rather than peripheral retinal activity.

Neurophysiological visual assessment in patients with idiopathic intracranial hypertension: visual evoked potential and multifocal field electroretinography

BackgroundDetermining the cause of visual deterioration in idiopathic intracranial hypertension (IIH) patients is of clinical necessity. This study aimed to study the effect of chronic increased ICP on the retina and optic nerve through objective electrophysiological measures in chronic IIH patients.MethodsThirty patients with chronic IIH and thirty age and sex-matched healthy controls were included in this study. Papilledema grade and CSF pressure were evaluated in the patients’ group. Both groups were submitted to visual evoked potentials (VEP) and multifocal electroretinogram (mfERG).ResultThe mean value of P100 latencies of the right and left on two check sizes, 1 deg and 15ṁ in chronic IIH patients, was significantly delayed than controls (P-value < 0.001 for each). Chronic IIH patients showed a significantly lower amplitude of the right and left R1, R2, R3, R4 & R5 compared to controls (P-value < 0.001, < 0.001) (P-value < 0.001, < 0.001) (P-value < 0.001, < 0.001) (P-value < 0.001, = 0.001) (P-value = 0.002, < 0.001), respectively. Also, patients showed a significantly delayed peak time of the right and left R1 and R2 compared to controls (P-value < 0.001, < 0.001) (P-value = 0.001, = 0.009), respectively. There was a significant positive correlation between each of CSF pressure and papilledema grade with right and left PVEP latencies. In contrast, there was no statistically significant correlation between either CSF pressure or papilledema grade and PVEP amplitudes in both eyes.ConclusionIn chronic IIH patients, both optic nerve dysfunction and central retinal changes were identified, supported by VEP and the mfERG findings.

Assessment of the Human Retinal Neural Selectivity to Square Gratings’ Orientation with the Multifocal and Pattern Electroretinograms

The retinal response to particular orientations might start a signaling cascade of events that help to modulate eye growth and respond to myopia control treatments. The purpose of this study was to investigate the retinal electrical activity in response to grids of different spatial orientations. The multifocal (mfERG) and pattern (PERG) ERG responses of nine eyes (spherical equivalent of −0.45 ± 1.15 D; mean age of 32.9 ± 7.7 years) were recorded with four grids (1.2 cpd) oriented at 60°, 90°, 120° and 180° under pupils’ dilation. The mfERG was analyzed by retinal eccentricity, quadrants and meridians with the same orientation of the grids. The response density of mfERG, the amplitudes of PERG and the implicit times of each peak from both tests were analyzed. The grid’s orientation did not evoke different implicit times in both tests. All retinal meridians showed higher response density with grids of parallel orientation to the meridian and lower response density with perpendicularly oriented grids. These differences were statistically significant in the horizontal and 60° meridians (p &lt; 0.050). PERG response did not change with the grids’ orientations. The mfERG was sensitive to detect changes in the outer retinal activity with variations in stimulus orientation. The paradigm of meridional analysis of mfERG results might be more sensitive to orientation changes than the traditional analysis by rings, quadrants or hemifields.

Adaptive Optics Flood Illumination Ophthalmoscopy in Nonhuman Primates: Findings in Normal and Short-term Induced Detached Retinae

To describe adaptive optics flood illumination ophthalmoscopy (AO-FIO) of the photoreceptor layer in normal nonhuman primates (NHPs) and in the case of a short-term induced retinal detachment (RD). Longitudinal fundamental research study. Four NHPs were used to image normal retinae with AO-FIO (in comparison with 4 healthy humans); 2 NHPs were used to assess the effects of RD. The photoreceptor layer (cone mosaic metrics, including cone density, cone spacing, and cone regularity) was followed with AO-FIO imaging (rtx1, Imagine Eyes) during a surgically induced RD in 2 NHPs using a vehicle solution containing dimethyl sulfoxide, classically used as a chemical solvent. We also performed functional testing of the retina (full-field and multifocal electroretinogram [ERG]). Correlation of cone mosaic metrics (cone density, spacing, and regularity) between normal retinae of NHPs and humans, and cone metrics, power spectrum, and ERG wave amplitudes after RD. Imaging features were very similar in terms of cone reflectivity, cell density, regularity, and spacing values, showing strong positive correlations between NHPs and humans. After RD, AO-FIO revealed several alterations of the cone mosaic slowly recovering during the 3 months after the reattachment, which were not detected functionally by ERG. These results demonstrate by invivo AO-FIO imaging the transient structural changes of photoreceptors after an RD in the primate retina. They also provide an interesting illustration of the AO-FIO potential for investigating photoreceptor toxicity during preclinical studies in NHPs with a high translatability to human studies. Proprietary or commercial disclosure may be found after the references.

Acute zonal occult outer retinopathy misdiagnosed as giant cell arteritis: a challenging case

Background: Acute zonal occult outer retinopathy (AZOOR) is a rare autoimmune retinopathy that is challenging to diagnose and treat. It usually presents with subtle fundus changes and severe visual symptoms. Herein, we report a challenging case of AZOOR, emphasizing that multimodal imaging could be valuable in diagnosis and monitoring of treatment response.&#x0D; Case Presentation: A 53-year-old woman presented to the emergency department with a one-week history of subacute, severe, painless vision loss without photopsia in her right eye. Her best-corrected distance visual acuity was 20/800 in the right eye and 20/20 in the left eye. Slit-lamp examination findings were unremarkable, and intraocular pressure was normal in both eyes. Initially, fundus examination findings appeared normal; however, serum levels of inflammatory markers were elevated. Brain and orbital magnetic resonance imaging results were unremarkable. A relative afferent pupillary defect was present in subsequent follow-up examinations at the hospital. The patient initially received a diagnosis of posterior ischemic optic neuropathy secondary to occult giant cell arteritis, underwent steroid treatment, and was evaluated by rheumatology and neurology consultants. Both consultants concurred with the presumed diagnosis. Subsequent multimodal imaging in the ophthalmology clinic revealed a trizonal pattern of fundus autofluorescence. Corresponding to these areas, we noted a loss of the ellipsoid zone on optical coherence tomography, depression on multifocal electroretinogram, and scotoma on visual field testing. Accordingly, the diagnosis of AZOOR was made. The patient was referred back to the rheumatologist for initiation of steroid-sparing treatment, and methotrexate was administered. Five months after the initial presentation, the patient showed significant visual field improvement in both eyes.&#x0D; Conclusions: Eye care practitioners should consider AZOOR in the differential diagnosis of patients with subacute painless severe unilateral vision loss and unremarkable findings on fundus examination. Multimodal imaging could be valuable in diagnosis and monitoring of treatment response, as observed in the current case. Further studies with larger sample sizes are needed to confirm the value of multimodal imaging and the available management options for AZOOR.

Association between relative peripheral refraction and corresponding electro-retinal signals.

Considering the potential role of the peripheral retina in refractive development and giventhat peripheral refraction varies significantly with increasing eccentricity from the fovea, we investigated the association between relative peripheral refraction (RPR) and corresponding relative peripheral multifocal electroretinogram (mfERG) responses (electro-retinal signals) from the central to the peripheral retina in young adults. Central and peripheral refraction using an open-field autorefractor and mfERG responses using an electrophysiology stimulator were recorded from the right eyes of 17 non-myopes and 24 myopes aged 20-27 years. The relative mfERG N1, P1 and N2 components (amplitude density and implicit time) of a mfERG waveform were compared with the corresponding RPR measurements at the best-matched eccentricities along the principal meridians, that isatthe fovea (0°), horizontal (±5°, ±10° and ± 25°) and vertical meridians (±10° and ± 15°). The mean absolute mfERG N1, P1 and N2 amplitude densities (nV/deg2 ) were maximum at the fovea in both non-myopes (N1: 57.29 ± 14.70 nV/deg2 , P1: 106.29 ± 24.46 nV/deg2 , N2: 116.41 ± 27.96 nV/deg2 ) and myopes (N1: 56.25 ± 15.79 nV/deg2 , P1: 100.79 ± 30.81 nV/deg2 , N2: 105.75 ± 37.91 nV/deg2 ), which significantly reduced with increasing retinal eccentricity (p < 0.01). No significant association was reported between the RPR and corresponding relative mfERG amplitudes at each retinal eccentricity (overall Pearson's correlation, r=-0.25 to 0.26, p ≥ 0.09). In addition, the presence of relative peripheral myopia or hyperopia at extreme peripheral retinal eccentricities did not differentially influence the corresponding relative peripheral mfERG amplitudes (p ≥ 0.24). Relative peripheral mfERG signals are not associated with corresponding RPR in young adults. It is plausible that the electro-retinal signals may respond to the presence of absolute hyperopia (and not relative peripheral hyperopia), which requires further investigation.

DAPSONE-INDUCED TOXIC MACULOPATHY IN LEPROSY PATIENT

Introduction: Dapsone has been widely used as a part of multidrug therapy for leprosy patients. Ocular side effects are rare. Ocular toxicity manifestations include retinal necrosis, optic atrophy, macular infarction, bilateral exudative retinal detachment, and choroidal detachment. We reported a rare case of dapsone-induced toxic maculopathy in a leprosy patient. Case Report: A 32-year-old male complained of blurred vision and a gray spot in central vision in the left eye (LE) for one month prior to admission. He had been treated with multidrug therapy (MDT) for leprosy for seven months. The MDT consists of dapsone, clofazimine, and rifampicin. The best-corrected visual acuity (BCVA) of the right eye (RE) and the LE were 6/6 and 6/12, respectively. A funduscopy of the LE showed decreased macular reflex. A color vision defect following the tritan axis was found in the LE. The Humphrey visual field (HVF) test of the LE revealed a central scotoma. Macular optical coherence tomography (OCT) showed intraretinal hyperreflectivity and subretinal fluid. Dapsone was then stopped in collaboration with a dermatologist. Two months after the discontinuation of Dapsone, the BCVA of the LE improved to 6/7.5, then 6/6 three months later. Color vision, macular OCT, and HVF tests revealed improvements. Multifocal ERG of both eyes (BE) also showed improvement in N1 and P1 wave amplitude in both eyes on 9-month follow-up after dapsone discontinuation. Discussion: Instead of direct drug toxicity, the mechanism of ocular side effects is thought to be ischemia caused by two distinct mechanisms. Macular ischemia is caused by acute, severe peripheral hypoxia and the physical effect of red cell fragmentation due to the hemolytic process. After discontinuation of dapsone, this case showed improvement in visual function and macular structure. Conclusion: Toxic maculopathy may be present in leprosy patients receiving dapsone treatment, although it is uncommon. Regular follow-up and evaluation of visual function and macular involvement are essential. Early detection of dapsone-induced toxic maculopathy and prompt discontinuation of dapsone may result in an improvement of visual functions.

Observations for Sjögren’s Pigment Epithelial Reticular Dystrophy in a 16-Year-Old Boy—An Extremely Rare Retinal Case Report

The purpose of this publication is to present an extremely rare case of Sjögren's pigment epithelial reticular dystrophy. So far, 10 such publications have been found in world literature. A 16-year-old boy was diagnosed due to a slight loss of visual acuity, confirmed in static perimetry/24-2/. Abnormal dense clusters of retinal pigment epithelium (RPE) cells forming a reticular network pattern (resembling a fishing net) with marked knots were detected by fundoscopy in the macular area and the mid-periphery of the retina. No abnormalities were found in the anterior segment, intraocular pressure, kinetic perimetry, Ishihara or Farnsworth D-15 tests or OCT. Fluorescein angiography confirmed blocked fluorescence from the choroidal vessels caused by the pigment in RPE. An autofluorescence test showed hypofluorescent foci corresponding to symmetrical and bilateral retinal hyperpigmentation with an RPE reticular pattern. Multifocal ERG (mfERG) revealed slight cone photoreceptor and bipolar bioelectrical dysfunction. Electrooculography (EOG) showed significant asymmetry (Arden Ratio 1.8), suggesting bioelectrical dysfunction of RPE/photoreceptors. Flash ERG (ERG) revealed only slight increase in implicit time of the a and b waves of the rod and cone responses and exclude cone-rod dystrophies. This article highlights the importance of the results of ophthalmoscopy, fluorescein angiography, autofluorescence, mfERG, fERG, EOG and genetic tests for Sjögren's reticular dystrophy with a pathogenic variant in the region of the C2 gene-c.841_849+19del (dbSNP rs9332736).

Use of multifocal electroretinograms to determine stage of glaucoma.

To determine whether multifocal electroretinograms (mfERGs) recorded with natural pupils and skin electrodes can be used to determine the stage of open angle glaucoma (OAG). Two hundred eighteen eyes of 132 OAG patients and 62 eyes of 62 normal subjects whose best-corrected visual acuity (BCVA) was 0.1 logarithm of the minimum angle of resolution (logMAR) units (20/25) or less were studied. The mean deviations (MDs) obtained by Humphrey Visual Field Analyzer (HFA), optical coherence tomographic (OCT) images, and mfERGs were analyzed. The glaucoma was classified into 4 stages: preperimetric glaucoma (PPG), early stage, moderate stage, and advanced stage glaucoma. The parameters of the mfERGs examined were the amplitudes of the two positive peaks (P1, P2) of the second order kernels in the nasal and temporal fields within the central 15° diameter. The mean age of all participants (patients and normals) was 63.8 ± 10.8 years. With the progression of glaucoma, the amplitudes of P1 in the nasal hemifield increased and the amplitudes of P2 decreased. The nasal to temporal ratio (N/T ratio) of the P1 amplitudes and the negative slope of the line between P1 and P2 (P1P2 Slope) in the nasal field were larger at each glaucoma stage except at the PPG stage. Both the N/T amplitude ratio and P1P2 Slope were weakly but significantly correlated with the MD (r = -0.3139, P<0.0001; r = 0.4501, P<0.0001, respectively), and the OCT parameters (all P<0.0001) except the outer layer thickness. Our findings indicate that the amplitudes of P1 and P2 of the second order kernel of the mfERGs in the nasal field of the center region can be good markers for the stages of glaucoma.

Functional and structural readouts for early detection of retinal involvement in multiple sclerosis.

The retina, a window into the brain, allows for the investigation of many disease-associated inflammatory and neurodegenerative changes affecting the central nervous system (CNS). Multiple sclerosis (MS), an autoimmune disease targeting the CNS, typically impacts on the visual system including the retina. Hence, we aimed to establish innovative functional retinal measures of MS-related damage, e.g., spatially resolved non-invasive retinal electrophysiology, backed by established morphological retinal imaging markers, i.e., optical coherence tomography (OCT). 20 healthy controls (HC) and 37 people with MS [17 without history of optic neuritis (NON) and 20 with (HON) history of optic neuritis] were included. In this work, we differentially assessed photoreceptor/bipolar cells (distal retina) and retinal ganglion cell (RGC, proximal retina) function besides structural assessment (OCT). We compared two multifocal electroretinography-based approaches, i.e., the multifocal pattern electroretinogram (mfPERG) and the multifocal electroretinogram to record photopic negative response (mfERG PhNR ). Structural assessment utilized peripapillary retinal nerve fiber layer thickness (pRNFL) and macular scans to calculate outer nuclear thickness (ONL) and macular ganglion cell inner plexiform layer thickness (GCIPL). One eye was randomly selected per subject. In NON, photoreceptor/bipolar cell layer had dysfunctional responses evidenced by reduced mfERG PhNR -N1 peak time of the summed response, but preserved structural integrity. Further, both NON and HON demonstrated abnormal RGC responses as evidenced by the photopic negative response of mfERG PhNR (mfPhNR) and mfPERG indices (P < 0.05). Structurally, only HON had thinned retina at the level of RGCs in the macula (GCIPL, P < 0.01) and the peripapillary area (pRNFL, P < 0.01). All three modalities showed good performance to differentiate MS-related damage from HC, 71-81% area under curve. In conclusion, while structural damage was evident mainly for HON, functional measures were the only retinal read-outs of MS-related retinal damage that were independent of optic neuritis, observed for NON. These results indicate retinal MS-related inflammatory processes in the retina prior to optic neuritis. They highlight the importance of retinal electrophysiology in MS diagnostics and its potential as a sensitive biomarker for follow-up in innovative interventions.

Evaluation of Fundus Function in Mature Cataract Patients by Visual Electrophysiology

Purpose. To explore the value of visual electrophysiology in evaluating the fundus function of mature cataract patients. Methods. 124 mature cataract patients (153 eyes) were examined before cataract surgery; the examinations included best corrected visual acuity (BCVA), pattern visual evoked potential (PVEP), full‐field electroretinogram (ffERG), and multifocal electroretinogram (mfERG). According to the postoperative fundus conditions, the subjects were divided into two groups: the no fundus disease group and the fundus disease group. Approximately one month after the operation, BCVA was measured, and visual electrophysiology was performed on subjects who had a stable fundus condition and had not received treatment for fundus disease. Results. One month after cataract surgery, BCVA ≤ 0.3 logMAR was found in 60 eyes (96.8%) without fundus disease and 59 eyes (64.8%) with fundus disease. Compared with the group without fundus disease, the preoperative electrophysiological examination of the group with fundus disease showed that the amplitude of ffERG waves and the amplitude density of the P1 wave in the 2nd to 5th rings of mfERG were decreased (all P &lt; 0.05). ffERG and mfERG can be used for differential diagnosis of fundus disease (all P &lt; 0.05), while PVEP has no significant diagnostic value for fundus disease (all P &gt; 0.05). In the group without fundus disease, the amplitude of the PVEP 15′ P100 wave and the amplitude of dark‐adapted (DA) 0.01 b‐wave, DA 3.0 a‐wave, and DA 10.0 a‐wave were negatively correlated with postoperative logMAR BCVA (all P &lt; 0.05). In the group with fundus disease, the amplitude of PVEP and ffERG and the amplitude density of mfERG were negatively correlated with postoperative logMAR BCVA (all P &lt; 0.05). In the eyes of cortical cataracts, some parameters of PVEP, ffERG, and mfERG were significantly different before and after surgery. In the eyes of nuclear cataracts, some parameters of ffERG and mfERG were significantly different before and after surgery. In the eyes of posterior subcapsular cataracts, some parameters of PVEP and ffERG were significantly different before and after surgery. Conclusions. ffERG and mfERG can be used to detect fundus disease in mature cataract patients. The preoperative visual electrophysiological examination has high clinical value in predicting postoperative vision of mature cataract patients with fundus disease. Different types of cataracts have different effects on electrophysiological examination results. When interpreting the electrophysiological report, it is necessary to consider the existence of cataracts. This trial is registered with 2019-K068.

Analysis of the Outcomes of the Screen-Time Reduction in Computer Vision Syndrome: A Cohort Comparative Study.

To analyze the outcomes of screen-time reduction on the foveal responses that associates computer vision syndrome (CVS) using multifocal electroretinogram (mfERG) examination. This prospective multicenter cohort comparative study included 49 eyes of 49 medical students divided into two groups. Group A (control group) included 25 eyes with no CVS diagnosis while group B (CVS group) included 24 eyes with CVS diagnosis. All students responded to the valid and reliable CVS-Form 3 (CVS-F3) questionnaire and underwent complete ophthalmic and mfERG examinations twice at the time recruitment in the study and four weeks after strict reduction of the daily screen-hours to ≤1 screen-hour daily to document associated foveal responses. We documented statistically significant reduction in foveal responses in CVS versus control groups in mean mfERG Rings 1, 2, and 5 with Quadrants 1, 2, and 4 (P=<0.0001, 0.0001, 0.0003, 0.001, 0.002, and 0.006, respectively). Following the screen-time reduction, the second mfERG examination revealed significant post-reduction improvements in foveal responses in CVS group particularly in mean mfERG Rings 1, 2, 3, and 5 with Quadrants 1 and 4 (P=<0.0001, <0.0001, 0.0005, 0.02, <0.0001, and 0.04, respectively). This study documented the screen-induced foveal dysfunction that associates CVS using mfERG examination, which revealed remarkable significant improvements in foveal responses in the 4 weeks following strict screen-time reduction. These improvements were also associated with corresponding improvements in the visual performances. We suggest that the potential screen-induced foveal dysfunction outcomes might be reversible with strict screen-time reduction. We also recommend that educational institutional policies should limit online education-hours and redesign the mandated computer system use program to guard against visual sequelae of CVS. ClinicalTrials.gov (ID: NCT04405648).

Evaluation of retinal function and morphology in isoametropic amblyopia.

To observe the photoreceptor anomalies in cases of ametropic amblyopia. A prospective study with 25 isoametropic amblyopic children in the age group of 5-14 years and 25 age-matched controls was done. Examination included refraction, best-corrected visual acuity (BCVA), and color vision. Adaptive optics (AO) and multifocal electroretinogram (mf-ERG) were done to assess the anatomy and function of photoreceptors. The subgroup analysis of the improved and non-improved groups was done. The mean cone density in cases and control in the superior, temporal, and nasal quadrants was respectively as follows (21640 ± 5713, 24040 ± 3386, P = 0.01) (19755 ± 6282, 21832 ± 2911, P = 0.03) (19897 ± 5418, 22171 ± 3660, P = 0.01) (20768 ± 4799, 22819 ± 3241, P = 0.01). The amplitude of N1 wave and P1 wave in cases was significantly low compared to the controls. Cases with subnormal color vision had reduced BCVA (0.55 ± 0.018) in comparison to the children with normal response (0.350 ± 0.014). Cone density was also significantly reduced in children with subnormal color vision. Sixteen out of 25 cases showed BCVA improvement with spectacles. Baseline cone density was found to be significantly higher in the improved group. There was no correlation between BCVA and AO parameters. Patients with ametropic amblyopia show subnormal photoreceptor properties than controls. Low cone density may be associated with defective color vision and poor prognosis in these cases.

Electroretinogram changes before and after silicone oil removal in eyes with macula-off rhegmatogenous retinal detachment

Background: Pars plana vitrectomy (PPV) with silicone oil (SO) injection for rhegmatogenous retinal detachment (RRD) repair may adversely affect electroretinographic responses. This study was aimed at assessing retinal function using electrodiagnostic testing after successful PPV with SO tamponade in the eyes with macula-off RRD.&#x0D; Methods: In this interventional comparative study, eligible participants were recruited prospectively over 1 year. We included the eyes that underwent a single successful three-port PPV with SO tamponade for the primary repair of macula-off RRD. Full-field electroretinogram (ffERG) and multifocal electroretinogram (mfERG) were recorded 1 day before and 3 days after SO removal. The amplitude and implicit time of the a- and b-waves for ffERG and P1 and N1 waves for mfERG were evaluated. The unaffected fellow eyes of the patients were selected as controls.&#x0D; Results: We included the ten eyes of ten patients (seven men and three women) with a mean (standard deviation) age of 58.8 (6.2) years. The mean (SD) interval between the diagnoses of macula-off RRD and PPV was 11.7 (3.6) days. The mean (SD) duration of SO tamponade was 147.8 (34.9) days. Using ffERG, significantly lower a- and b-wave amplitudes were found in the eyes before and after SO removal or compared to the unaffected fellow eyes (all P &lt; 0.05). Using the mfERG, treated eyes had significantly lower P1 amplitudes in the central R1+R2+R3 rings and in the R4 and-R5 peripheral rings of the macular area in the eyes before and after SO removal or compared to the unaffected fellow eyes (all P &lt; 0.05). The wave implicit time in ffERG and mfERG did not differ significantly in the eyes before and after SO removal or compared to the unaffected fellow eyes (all P &gt; 0.05).&#x0D; Conclusions: The electrical retinal response density in ERG waveforms increased following SO removal, indicating amelioration of the electrical activity of the retina and macula. These results indicate that the adverse effects of SO tamponade on electroretinography responses may be reversible with removal. In addition, ffERG and mfERG can be used to monitor retinal function in the eyes with macula-off RRD and SO tamponade. Further clinical trials are required to verify the preliminary findings of this study.

Comparison of DTL and gold cup skin electrodes for recordings of the multifocal electroretinogram

ObjectiveTo compare mfERG recordings with the Dawson–Trick–Litzkow (DTL) and gold cup skin electrode in healthy young and old adults and to test the sensitivity of both electrodes to age-related changes in the responses.MethodsTwenty participants aged 20–27 years (“young”) and 20 participants aged 60–75 (“old”) with a visual acuity of ≤ 0 logMAR were included. The mfERG responses were recorded simultaneously using DTL and skin electrodes. P1 amplitudes, peak times and signal-to-noise ratios (SNRs) were compared between both electrodes and across age groups, and correlation analyses were performed. The electrode’s performance in discriminating between age groups was assessed via area under curve (AUC) of receiver operating characteristics.ResultsBoth electrodes reflected the typical waveform of mfERG recordings. For the skin electrode, however, P1 amplitudes were significantly reduced (p < 0.001; reduction by over 70%), P1 peak times were significantly shorter (p < 0.001; by approx. 1.5 ms), and SNRs were reduced [(p < 0.001; logSNR ± SEM DTL young (old) vs gold cup: 0.79 ± 0.13 (0.71 ± 0.15) vs 0.37 ± 0.15 (0.34 ± 0.13)]. All mfERG components showed strong significant correlations (R2 ≥ 0.253, p < 0.001) between both electrodes for all eccentricities. Both electrodes allowed for the identification of age-related P1 changes, i.e., P1-amplitude reduction and peak-time delay in the older group. There was a trend to higher AUC for the DTL electrode to delineate these differences between age groups, which, however, failed to reach statistical significance.ConclusionsBoth electrode types enable successful mfERG recordings. However, in compliant patients, the use of the DTL electrode appears preferable due to the larger amplitudes, higher signal-to-noise ratio and its better reflection of physiological changes, i.e., age effects. Nevertheless, skin electrodes appear a viable alternative for mfERG recordings in patients in whom the use of corneal electrodes is precluded, e.g., children and disabled patients.

Retinal and Visual Pathways Involvement in Carriers of Friedreich's Ataxia.

Friedreich's ataxia (FRDA) is a rare autosomal recessive neurodegenerative disorder due to the homozygous pathological expansion of guanine-adenine-adenine (GAA) triplet repeats in the first intron of the FXN gene, which encodes for the mitochondrial protein frataxin. In the visual system, the typical manifestations are ocular motility abnormality, optic neuropathy, and retinopathy. Despite the evidence of ophthalmological impairment in FRDA patients, there is a lack of information about the morpho-functional condition of the retina and of the optic pathways in healthy heterozygous carriers of Friedreich's ataxia (C-FRDA). Ten C-FRDA subjects (providing 20 eyes) and thirty-five Controls (providing 70 eyes) underwent a complete neurological and ophthalmological examination comprehensive of functional (full-field Electroretinogram (ffERG), multifocal Electroretinogram (mfERG), Visual Evoked Potential (VEP), and Pattern Reversal Electroretinogram (PERG)) and morphological assessments (Optical Coherence Tomography, OCT) of the retina, macula, retinal ganglion cells, and visual pathways. The groups' data were compared using a two-sample t-test. Pearson's test was used to investigate the morpho-functional correlations. Statistically significant differences (p &lt; 0.01) between C-FRDA and Control eyes for the values of the following parameters were found: ffERG b-wave amplitude, mfERG Response Amplitude Densities, PERG P50 implicit time and P50-N95 amplitude, VEP P100 implicit time, Retinal Nerve Fiber Layer (RNFL) Overall, and Nasal thickness. The values of the OCT macular volume were not statistically different (p &gt; 0.01) between the two Groups. Therefore, our data suggest that, in C-FRDA, a dysfunction of retinal elements without morphological macular impairment may occur. In addition, a morphological impairment of RNFL associated with an abnormal neural conduction along the visual pathways can be also detected.

Optical coherence tomography and electrophysiological analysis of proptotic eyes due to thyroid-associated ophthalmopathy

PurposeTo study the degree of morphological and functional changes in thyroid-associated ophthalmology (TAO) patients using optical coherence tomography and electrophysiological studies and investigate their clinical correlation.MethodsA cross-sectional study including 40 patients with TAO and a control group with age- and sex-matched healthy subjects. All subjects underwent a complete ophthalmological examination, proptosis evaluation, spectral domain optical coherence tomography, and electrophysiological tests (pattern and multifocal electroretinograms, and visual evoked potentials).ResultsOn multiple regression analysis, the degree of proptosis and P50 amplitude were the most important predictors of central foveal thickness (CFT) (β = − 0.56 and 0.39 and p = 0.03 and 0.01, respectively); while duration of the disease, and clinical activity score (CAS) were the most important predictors of average RNFL thickness (β = 0.67 and − 0.81 and p = 0.004 and < 0.001, respectively).ConclusionIn the absence of fundus changes, macular thinning along with functional alterations noticed by pattern and multifocal electroretinogram could indicate presence of subclinical retinopathy in TAO cases.