Multifocal Electroretinography Research Articles

Williams-Beuren Syndrome Case with Atypical Flattening of Fovea Centralis, Decreased ILM-RPE Thickness and Irregular Corneal Surface

This is an observational case report. The medical history of the patient was assessed. Ophthalmologic examination including slit-lamp biomicroscopy, dilated indirect ophthalmoscopy, fundus autofluorescence and optical coherence tomography (OCT) imaging, full-field electroretinography, multifocal electroretinography and corneal topography was performed and literature was reviewed.

Changes in Pattern and Multifocal Electroretinogram in Tuberculosis Patient with Ethambutol Therapy

Introduction: Tuberculosis (TB) is a world health problem, especially in Indonesia as the third biggest country for new emerging TB patients. Ethambutol is one of the standard therapies to treat TB patients in Indonesia. Ethambutol has a side effect called ethambutol optic neuropathy which is hard to diagnose due to normal fundus appearance in most cases and therefore often detected late. Early detection is necessary so that permanent damage can be prevented. Examination pattern electroretinography (pERG) and multifocal electroretinography (mfERG) have the advantage to detect and confirm ocular toxicity by ethambutol after the clinical problem had emerged. It is not yet known neither pERG nor mfERG could detect any changes to detect ethambutol ocular toxicity before the clinical problem emerged. Methods: This study was a prospective clinical trial with 40 eyes samples and analyzed with paired t and Wilcoxon tests. The ocular examination was conducted using the Snellen chart, HRR Richmond Plates, Pelli Robson, pERG, and mfERG in tuberculosis category 1 patient with 2 months follow-up. Result: Visual acuity, color, and contrast sensitivity were normal in all patients for 2 months follow-up period. In pERG examination, the mean implicit time wave P50 was shortened by -1.27± 4.71 mS (p=0.049), and the mean amplitude wave N95 was reduced by -0.93± 4.49 ?V (p=0.038). Both were statistically significant. In the mfERG examination, we did not find any statistically significant changes in both wave N1 and P1. Conclusion: Changes in pattern ERG presented earlier compared to mfERG after ethambutol therapy for 2 months.

Macular vascular density and visual function after phacoemulsification in cataract patients with non-pathological high myopia: a prospective observational cohort study.

This study aimed to evaluate changes in macular vascular density and macular function in patients with high myopia cataract (HMC) after phacoemulsification surgery, using optical coherence tomography angiography (OCTA) and multifocal electroretinography (mfERG). Patients with cataracts scheduled for phacoemulsification surgery were divided into a high myopia group (axial length > 26.5mm) and a control group (22mm < axiallength ≤ 24.5mm). OCTA examinations were performed before surgery and at 1day, 1week, 1month, and 3-6months post-surgery, while mfERG was conducted before surgery and at 3-6months post-surgery. A total of 38 patients were included, of whom 20 were HMC patients and 18 were control patients. The macular vascular density significantly increased after phacoemulsification surgery in both groups, while foveal avascular zone area decreased significantly (HMC group: all p < 0.01; control group: all p < 0.05). Mean changes in macular vascular density were significantly greater in HMC patients than in the control group at 1day after surgery (all p < 0.05). The amplitude density and latency of P1 wave in all macular rings (Ring1-5) did not differ significantly before or after surgery in either group (all p > 0.1). Phacoemulsification may not affect HMC patients' macular mfERG responses within 3-6months post-surgery, but it may influence macular microcirculation. HMC patients should be closely monitored after surgery, as their retinal vascular density may fluctuate substantially in the early postoperative period.

Electrophysiological evaluation and 18-month follow-up of two regimens with aflibercept for neovascular age-related macular degeneration

PurposeTo compare two aflibercept treatment regimens and the electrophysiological outcome concerning cone and rod function in age-related macular degeneration (nAMD) over 18 months.Methods41 patients with treatment-naïve nAMD were randomized 1:1 to either arm 1 or 2. Arm 1 received three consecutive monthly aflibercept injections, followed by bimonthly treatment until week 52. Thereafter, a treat-and-extend (TAE) regimen was applied. Arm 2 was treated according to a TAE protocol throughout the 18-month follow-up. We assessed visual acuity (VA), central retinal thickness (CRT), injection rate and interval, and evaluated cone and rod function with full-field and multifocal electroretinography (ffERG, mERG).ResultsThere were no statistically significant differences in mean baseline VA, lesion type, age, gender, or symptom duration between the two arms. During the 18-month follow-up, mean VA improved in arm 1 (n = 19) from 63.5 ± 10.5 to 69.1 ± 9.2 letters; p = 0.098; and in arm 2 (n = 20) from 66.8 ± 13.6 to 73.9 ± 9.0 letters; p = .002. In both arms, mean CRT was significantly reduced; p < 0.000. At month 18, we found no significant difference in the number of injections or injection intervals between groups. Arm 1 had received 11.3 ± 1.7 injections vs. 10.9 ± 2.0 in arm 2. The mean injection interval was 9.2 ± 3.4 weeks vs. 9.5 ± 3.1, with 52% (n = 10) on the maximum 12-week interval in arm 1, and 50% (n = 10) in arm 2. The combined rod-cone a-wave amplitude significantly decreased over time; p = 0.043. The isolated rod b-wave amplitude showed a statistically significant decline; p = 0.026. The overall mERG amplitude and implicit time remained unchanged over time; p = 0.878 vs. p = 0.922. The central ring 1 mERG amplitude improved; p = 0.041, with an unaffected implicit time.ConclusionsAfter 18 months, both treatments arms have received a similar number of injections at comparable intervals. Electrophysiological evaluation shows no signs of toxicity concerning cone function. But ffERGs for the combined and isolated rod response have declined, possibly reflecting either toxic effects of the drug to rods or the natural course of the disease itself.

Twelve-year follow up of a case of autosomal recessive bestrophinopathy with transient resolution of retinal edema in one eye.

To report 12-year follow-up of a patient with ARB. A 25-year-old man presented with blurred vision in his both eyes (OU). Best-corrected visual acuity (BCVA) was 20/63 Snellen equivalent in the right eye (OD) and 20/32 Snellen equivalent in the left eye. The intraocular pressures and anterior segment examination were unrevealing in OU. Posterior segment examination revealed multiple yellowish flecks and dots in the posterior pole in OU. Optical coherence tomography (OCT) showed subretinal fluid (SRF), intraretinal hyporeflective spaces, elongated and shaggy photoreceptors and outer retinal defects. Fundus autofluorescence demonstrated mottling hyperautofluorescence and hypoautofluorescence in the posterior pole in OU. Fluorescein angiography illustrated hyperfluorescence in the posterior pole and surrounding the arcades in OU. Multifocal electroretinography objectified mild to markedly abnormal responses in all ring areas in OU. Molecular genetic testing confirmed two heterozygous sequence variations in the BEST1 gene. At 4 years of follow-up, OCT revealed a complete resolution of SRF and a partial resolution of intraretinal hyporeflective spaces in the OD with corresponding improvement in the BCVA to 20/23 Snellen equivalent in the OD, even though outer retinal defects persisted. Our patient denied recent changes in his alimentary habits and medical history at that time. Posteriorly, SRF and intraretinal hyporeflective spaces reappeared in the OD. To the best of our knowledge, this is the first case report of ARB with a transient resolution of retinal edema in one eye without medical treatment and dietary therapy.

Outcomes of transcorneal electrical stimulation therapy in the early stages of retinitis pigmentosa.

To investigate the effect of transcorneal electrical stimulation (TES) therapy in patients with retinitis pigmentosa (RP). We performed TES therapy in 21 patients with RP in 12 sessions with 1-week intervals. The following parameters obtained before and after the TES therapy were compared statistically; the best corrected visual acuity (BCVA, logMAR), Ishihara color vision level, multifocal electroretinography (mf-ERG) response, automated visual field (VF) outcome, and the 25-item low vision quality-of-life (LVQOL) questionnaire points. The mean age of patients (6 females; 15 males) was 31.67 ± 9.80 years (20-50 years). While increases in BCVA level, color vision level, mf-ERG response in p1 amplitude of ring 1, and LVQOL questionnaire points were statistically significant, changes in VF test and other mf-ERG responses were not. Twenty of the patients (95.24%) stated that they were satisfied with the TES therapy. No considerable side effect was observed in any patient due to the therapy. The TES therapy may be an effective and safe treatment modality in slowing the RP progression, especially in the early stages of the disease. Longer-term follow-ups in larger patient populations are warranted.

Multifocal electroretinography in assessment of the functional state of the central retina in patients with retinitis pigmentosa

To evaluate the information content of multifocal electroretinography (mfERG) in the diagnostics of the functional state of the central retina in retinitis pigmentosa (RP). The study included 115 patients (228 eyes) with PR and 15 people (30 eyes) who comprised the control group. All subjects underwent standard ophthalmological examination, computer perimetry, color vision study, retinal spectral optical coherence tomography, ganzfeld electroretinography (gERG) and mfERG. The relationship between mfERG parameters and the degree of gERG changes, as well as various functional and morphological parameters of the retina was assessed. Visual acuity and perimetry indices varied over a wide range. GERG was unrecordable in 50.4% of cases. MfERG was registered in 214 (98.3%) eyes with varying degrees of change in visual acuity, visual field and gERG parameters. A medium degree positive relationship was revealed between the biopotential density of the retina in the foveal and parafoveal zones and visual acuity (rs=0.68; 0.63), a high degree - between the density of ttotal biopotential of the central retina (DValue) and the average light sensitivity (rs=0.9), a weak degree - between DValue and the thickness and volume of the peripheral retina (rs=0.37; 0.42), a medium negative correlation was found between the average defect in light sensitivity and the biopotential density in the periphery (Rings 4-5) on mfERG, DValue (rs= -0.67; -0.65; -0.69). MfERG detects retinal dysfunctions at an early stage of RP, in eyes with high visual acuity, normal parameters of the central visual field and gERG, as well as in low visual acuity, a pronounced decrease in light sensitivity, unrecordable gERG. MfERG can be informative in the selection of patients with RP for gene therapy.

Evaluation of Corneal and Retinal Toxicity in Rheumatoid Arthritis Patients Treated with Hydroxychloroquine

Introduction: The study aimed to assess the ocular toxicity of hydroxychloroquine (HCQ) by confocal microscopy, multifocal electroretinography (mfERG), and scanning laser polarimetry with variable corneal compensation (GDxVCC) in patients with rheumatoid arthritis (RA). Methods: A cross-sectional, comparative case series study was retrospectively conducted on 61 patients under HCQ treatment for RA without fundoscopic anomalies (group 1), 65 RA patients with no HCQ treatment (group 2), and 27 normal subjects (group 3). A comprehensive ophthalmological examination, including confocal microscopy, mfERG, and GDxVCC, was performed in the three groups. Results: In group 1, the duration of treatment ranged from 19 to 96 months (54.9 ± 15.2 months). The mean cumulative dose of HCQ was 446.1 ± 164.0 g (range 114–864 g). Confocal microscopy revealed hyper-reflective abnormal particles in 45 patients (73.8%) and beaded, tortuous fibers in 34 patients (55.7%) in group 1. No corneal change was observed in the other two groups. The mfERG responses in the 6 concentric rings (R1–R6) among the three groups differed except at R3 (all p < 0.05), and data from R1–R6 were not significantly different between groups 2 and 3. The retinal nerve fiber layer thicknesses were statistically thinner in group 1 than in groups 2 and 3 (all p < 0.05). Conclusions: Early signs of corneal and neural retina structure changes were detected in patients with RA treated with HCQ. Whether these findings should be a mark of drug recession still needs further study and more evidence.

Longitudinal multimodal functional macular analysis after half-dose photodynamic therapy for central serous chorioretinopathy

BackgroundHalf-dose photodynamic therapy (HD-PDT) has been widely used for central serous chorioretinopathy (CSC) with good anatomical results. However, long-term functional outcomes after this treatment remain uncertain. This study aimed a longitudinal multimodal macular assessment, correlating functional and anatomical outcomes. MethodsThis is a retrospective study performed in a tertiary referral center including 111 eyes from 95 CSC patients. Data on best corrected visual acuity (BCVA), central macular thickness (CMT), central retinal sensitivity (CRS) using microperimetry (MP) and multifocal electroretinography (mfERG) at baseline and 3, 6, 12, 18, 24, 36, 48 and 60 months after treatment were registered. A correlation analysis was performed. ResultsMean follow-up was 34.5 ± 26.3 months. A significant improvement in BCVA and CMT was registered in all the visits. CRS significantly improved until 24 months (p < 0.001 at 12 months, p < 0.05 at 24 months), worsening afterwards. The mfERG amplitude of N1 and P1 waves significantly improved in the first 12 months, aggravating afterwards. The implicit time improved until 24 months, deteriorating after 48 months. This long-term decline was also described in some inactive untreated fellow eyes ConclusionsA multimodal longitudinal analysis of CSC patients after HD-PDT shows that, after the first 12 to 24 months, the significant sustained improvement in BCVA and CMT is not paired by a sustained improvement in macular sensitivity or electrical response. This long-term functional deterioration might result from the disease itself and not directly from the treatment .

Macular Telangiectasia type 2: multimodal assessment of retinal function and microstructure.

To assess the impact of neurodegenerative morphologic alterations due to macular telangiectasia type 2 (MacTel) on microperimetry (MP) and multifocal electroretinography (mfERG). Thirty-five eyes of 18 patients with MacTel were examined using spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF), mfERG and MP. Software was used to match SD-OCT B-scans with the corresponding retinal sensitivity map and multifocal electroretinograms (mfERGs), thus enabling direct structure/function correlation. Loss of the ellipsoid zone (EZ) had the strongest negative association with retinal sensitivity (16.77 dB versus 4.58 dB, adj. p < 0.001) of all parameters examined, and a limited negative effect on mfERGs (0.32 SD versus -1.97 SD adj. p = 0.121). Ellipsoid zone (EZ) irregularity was associated with reduced MP values but preserved mfERGs. There was a significant association between areas of inner retinal hyporeflectivity and loss of MP sensitivity (adj. p < 0.001) but the reduction in sensitivity was less than in locations with EZ loss. Areas of mfERG abnormality showed similar sensitivity loss with either inner retinal hyporeflectivity or EZ loss (adj. p = 0.063). In areas with EZ loss alone, preservation of the external limiting membrane (ELM) was associated with higher MP values than in areas with additional ELM loss; the integrity of the ELM alone was not associated with changes either in MP or mfERG. Increased FAF was observed in 51% of eyes, mixed/reduced FAF in 40%, and no abnormality was detected in 9% of eyes. The data suggest both MP and mfERG to be useful non-invasive modalities for detecting localised macular dysfunction in MacTel. The findings suggest a different sensitivity of the two modalities to inner and outer retinal changes in macular function and are therefore complementary.

Long-term visual pathway alterations after elemental mercury poisoning: report of a series of 29 cases

BackgroundThere are few clinical data on retinal involvement after acute exposure to high concentrations mercury and the available reports are based on a small number of patients suffering chronic exposure. The purpose of this paper is to report findings in workers acutely exposed to very high concentrations of mercury vapor with the aim of providing data on a possible direct retinal involvement.MethodsTwenty-nine patients and 16 controls were evaluated in a comparative case series. Mercury levels in blood and urine samples, visual acuity (VA), contrast sensitivity (CS), visual field (VF), color discrimination and optical coherence tomography (OCT) were recorded. The pattern reversal visual-evoked potentials (PRVEP), full-field and multifocal electroretinography (ffERG/mfERG), pattern electroretinography (PERG), systemic symptoms, presence of erethism, and electromyography (EMG) were also gathered. A descriptive analysis was performed. The correlations between variables also were studied.In addition, electrophysiological data from those patients with deeper VF defects (group 1) were compared with a normal control group.ResultsTwenty-six workers exhibited symptoms of erethism. The EMG showed sensorimotor polyneuropathy and multiple mononeuropathy. The VA was slightly affected in 48.27% (n = 14) of subjects. Loss of CS in at least one of four spatial frequencies and color vision alterations occurred in 96.5% (n = 28) and 44.8% (n = 13), respectively. VF alterations were identified in 72.4% (n = 21) patients. No morphologic changes were seen in the OCT scans. Latencies over 100 milliseconds and reduced amplitudes of P100 were found in the PRVEP (p < 0.05). The reduced amplitude of the b wave at the ffERG, of the P50 at the PERG and of the P1 wave at the mfERG results (p < 0.05) suggested that the outer retina was involved. Significant negative correlations among blood mercury levels, VA, and ffERG were observed.ConclusionsIn this case series, showed that acute exposure to mercury vapor had a hazardous effect on the visual system. Although neurologic and visual pathway involvement was clearly demonstrated, the differences found compared to control support the existence of a direct functional retinal damage and participation in impaired vision in mercury poisoning.

A novel 5-ring multifocal electroretinography stimulus for detecting hydroxychloroquine retinal toxicity

PurposeMultifocal electroretinogram (mfERG) shows great utility as a screening tool to detect early hydroxychloroquine (HCQ) retinopathy, but its widespread use is limited by the lack of accessibility and long test duration. In this study, we evaluated a novel concentric 5-ring mfERG stimulus to provide a simplified and rapid protocol for screening HCQ toxicity.MethodsPatients referred for HCQ retinopathy screening were consented to this observational cross-sectional study. Patients with amblyopia, high refractive error (more than 8 diopters), other retinal diseases precluding appropriate evaluation or history of retinal surgery were excluded. The data were collected from patients undergoing HCQ screening at a single center from July 2019 to March 2020. Patients were tested with the new concentric 5-ring mfERG stimulus, standard 61-hexagon mfERG stimulus, spectral domain optical coherence tomography and automated 10-2 visual fields. For the main outcome, the 5-ring mfERG was compared to 61-hexagon stimulus to determine the time-to-test completion and assess the association between ring (R1–R5) amplitude and ring ratio compared against cumulative dose, dose by real body weight and duration of therapy using Pearson correlation.ResultsIn total, 52 patients (104 eyes; 5 males and 47 females) were recruited with a mean age of 59 years (range 23–85 years). The 5-ring protocol was markedly quicker to perform (1.3 ± 0.2 min; mean (SD)) compared to the 61-hexagon protocol (5.2 ± 0.6 min), p < 0.0001; n = 10 patients. The new R2/R5 ring ratio showed a moderate correlation with daily dose (r = − 0.640), cumulative dose (r = − 0.581) and duration of therapy (r = − 0.417). Similar correlations were observed with the new R2/R4 ring ratio which were not significantly different from the new R2/R5 correlation coefficients. The new R2/R5 ring ratio demonstrated a stronger correlation with daily (p = 0.002) and cumulative dose (p = 0.0001) compared to the 61-hexagon stimulus.ConclusionsIn this exploratory study, our novel 5-ring mfERG protocol significantly shortened data acquisition time while providing comparable results to the standard 61-hexagon stimulus for detecting HCQ-induced electrophysiological changes that are correlated with HCQ dosages and treatment duration. Our protocol has the potential to be more clinically practical by simplifying routine screening.

Ocular Characteristics of Patients with Leber Congenital Amaurosis 6 Caused by Pathogenic RPGRIP1 Gene Variation in a Chinese Cohort.

Purpose To delineate the clinical and genetic characteristics of Chinese patients with RPGRIP1-associated Leber congenital amaurosis 6 (LCA6). Methods After screening 352 unrelated families with clinically diagnosed RP, five LCA6 patients with RPGRIP1 variations from unrelated Chinese families were identified. Full ophthalmology examinations, including decimal best-corrected visual acuity (BCVA), fundus photography, fundus autofluorescence imaging, spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (ffERG), multifocal electroretinography (mfERG), perimetry, and flash visual evoked potential (FVEP), were performed. Target next-generation sequencing (NGS) and Sanger sequencing were performed for the five patients to identify and to validate candidate disease-causing variants. Results Five patients were molecularly diagnosed as the LCA6 associated with RPGRIP1 variation, with typical clinical characteristics including congenital night blindness, nystagmus, and visual defect, at an early age. Interestingly, LCA6 exhibited extensive clinical heterogeneity and the changes in the morphology and function were not completely consistent in the five LCA6 patients. Case 1 showed extensive inferior-nasal retinal atrophy with a corresponding area of hypofluorescence in fundus autofluorescence, and the fundus photograph was nearly normal in cases 2 and 3. The ERG results displayed a moderately reduced rod-system response in cases 1 and 2 and a significant reduced rod-system response in case 3. Both case 4 and case 5 showed mottled pigmentation in fundi and an unrecordable rod and cone-system response in ERG. Moreover, we identified eight compound variants and one homozygous variant in the five patients with RPGRIP1. Conclusions This is the largest report focused on the clinical electrophysiological features of patients with associated LCA6 caused by the variation in the RPGRIP1 gene in the Chinese population with an enriched phenotypic and genotypic background of LCA6 to improve future gene therapies.

A Rare Case of Juvenile X-Linked Retinoschisis

Abstract Aim: To present a rare clinical case of X-linked retinoschisis, confirmed clinically, electrophysiologically and genetically. Material and methods: A 12-year-old boy underwent detailed ophthalmic examination including fundus photography, full-field, multifocal and pattern electroretinography, visual field testing, optical coherence tomography, which established the clinical diagnosis, confirmed also genetically. Results: The clinical findings included a slight loss of vision, central and paracentral scotomas, a characteristic spoke-wheel pattern appearance of the macula in fundoscopy and the pathognomic appearance of splitting of the retinal layers in the macula with foveal schisis with cystic spaces on OCT. Reduced cone and rod ERG responds were detected with the characteristic decreasing of b-ware near the isoelectric line. The genetic analysis found that the patient was hemizygous for the missense mutation c.598G&gt;A (p.Arg200Cys) of RS1 gene, coming from his asymptomatic mother. Conclusion: The comprehensive clinical, electrophysiological and genetic testing of patients with rare hereditary retinal dystrophies is essential for the correct diagnosis and the choice of therapeutic approach.

Zone-wise examination of optical coherence tomography features and their correspondence to multifocal electroretinography in eyes with nonproliferative diabetic retinopathy.

To examine (1) the retinal structure by optical coherence tomography (OCT) and function by means of multifocal electroretinography (mfERG) in eyes with and without nonproliferative diabetic retinopathy (NPDR) (2) for correspondence between local retinal function and OCT zones with retinal lesions. One hundred and thirty-two eligible participants (30 with nonproliferative DR (NPDR) and 102 with diabetes with no DR) underwent comprehensive ophthalmic examination, optical coherence tomography for retinal thickness measures, mfERG, and ultra-wide field fundus photography. OCT Early Treatment Diabetic Retinopathy Study (ETDRS) grid was overlaid on to mfERG plots. Those with NPDR had significantly thicker full retinal measures in the nine (ETDRS) zones compared to no DR. mfERG P1 latencies in rings 1-6 were significantly delayed, while the response densities in rings 4-6 were lower in the NPDR group. Significant negative correlation was noted between OCT thickness and mfERG P1 response densities in many ETDRS zones. Significant positive correlation was noted between P1 latencies and OCT thickness in a few zones. The combination of cystic spaces, microaneurysms, and hard exudates were present in all zones and were associated with a decrease in P1 response densities compared to no lesions. Reduced P1 response densities were associated with a sporadic delay in the mfERG latencies and vice versa. The number of lesions did not show correspondence to the mfERG measures. In eyes with NPDR, retinal function is differentially correlated with the DR lesions on OCT and can be assessed using multimodal imaging modalities.

Localized Structural and Functional Deficits in a Nonhuman Primate Model of Outer Retinal Atrophy.

PurposeCell-based therapy development for geographic atrophy (GA) in age-related macular degeneration (AMD) is hampered by the paucity of models of localized photoreceptor and retinal pigment epithelium (RPE) degeneration. We aimed to characterize the structural and functional deficits in a laser-induced nonhuman primate model, including an analysis of the choroid.MethodsMacular laser photocoagulation was applied in four macaques. Fundus photography, optical coherence tomography (OCT), dye angiography, and OCT-angiography were conducted over 4.5 months, with histological correlation. Longitudinal changes in spatially resolved macular dysfunction were measured using multifocal electroretinography (MFERG).ResultsLesion features, depending on laser settings, included photoreceptor layer degeneration, inner retinal sparing, skip lesions, RPE elevation, and neovascularization. The intralesional choroid was degenerated. The normalized mean MFERG amplitude within lesions was consistently lower than control regions (0.94 ± 0.35 vs. 1.10 ± 0.27, P = 0.032 at month 1, 0.67 ± 0.22 vs. 0.83 ± 0.15, P = 0.0002 at month 2, and 0.97 ± 0.31 vs. 1.20 ± 0.21, P < 0.0001 at month 3.5). The intertest variation of mean MFERG amplitudes in rings 1 to 5 ranged from 13.0% to 26.0% in normal eyes.ConclusionsLaser application in this model caused localized outer retinal, RPE, and choriocapillaris loss. Localized dysfunction was apparent by MFERG in the first month after lesion induction. Correlative structure-function testing may be useful for research on the functional effects of stem cell–based therapy for GA. MFERG amplitude data should be interpreted in the context of relatively high intertest variability of the rings that correspond to the central macula. Sustained choroidal insufficiency may limit long-term subretinal graft viability in this model.

Correlation between optical coherence tomography angiography and multifocal electroretinogram findings in patients with diabetes mellitus

BackgroundDiabetic retinopathy is characterized by microvascular, neural and glial cell damage. Optical coherence tomography angiography (OCTA) can detect subclinical microvasculopathy while multifocal electroretinography (mfERG) can detect subclinical local retinal dysfunction before onset of clinically observable retinopathy. Here, we investigated the relationship between retinal dysfunction in multifocal electroretinography and vascular changes in optical coherence tomography angiography. MethodsThe study included 63 eyes of 63 diabetic patients without retinopathy (DM+DR-) and 68 eyes of 68 patients with non-proliferative diabetic retinopathy (NPDR). In addition, 64 eyes of 64 age and sex-matched subjects were included as the control group (CG). All subjects were evaluated using OCTA and mfERG. ResultsThe vascular density in the superficial and deep capillary plexus was significantly decreased in the DM+DR-group and the NPDR group compared with the CG group (except for the superficial foveal area, NPDR group vs. CG group) (p < 0.05). The vascular density of the superficial and deep parafoveal region was significantly decreased in the NPDR group compared to the DM+DR-group (p < 0.05). In circles of 2-, 5- and 10°, the amplitudes of the N1 and P1 waves were statistically significantly decreased in both the DM+DR- group and the NPDR group compared with the CG (p < 0.05). When the NPDR group was compared with the DM+DR- group, there was a statistically significant decrease in the amplitude of the N1 and P1 waves in the circles of 2- and 5° (p < 0.05). According to the correlation analysis, the amplitude and implicit times of the N1 and P1 waves showed weak-to-moderate correlation with vascular density (p < 0.05). ConclusionsThe decreased peaks of mfERG wave provides evidence regarding neurodegenerative effect of DM-associated hyperglycaemia. The decreased vascular density caused by hyperglycaemia was topographically associated with the retinal dysfunction and neurodegeneration.

Impact of Structural Changes on Multifocal Electroretinography in Patients With Use of Hydroxychloroquine.

PurposeTo investigate the relationship between retinal structure and macular function in eyes screened for hydroxychloroquine (HCQ) toxicity.MethodsParticipants referred for hydroxychloroquine retinopathy screening with spectral domain optical coherence tomography (SD-OCT) and multifocal electroretinogram (mfERG) testing were included in the analysis. Amplitude and implicit time of mfERG N1 and P1 responses were included in the analysis. Ring ratios were computed for amplitude values as the ratio of rings 1–3:5 (R1–3:R5). A control group of healthy participants was included for comparison of SD-OCT metrics.ResultsSixty-three eyes screened for HCQ retinopathy and 30 control eyes were analyzed. The outer nuclear layer (ONL) was significantly thinner in HCQ patients in the foveal (P = 0.008), parafoveal (P < 0.0001), and perifoveal (P < 0.0001) regions. The HCQ cohort was further divided into two subgroups according to the presence of structural clinically detectable retinopathy (i.e., structural damage as detected by multimodal imaging). HCQ eyes without retinopathy had a thinner ONL thickness in the foveal (P = 0.032), parafoveal (P < 0.0001), and perifoveal (P < 0.0001) regions and a thinner inner nuclear layer (INL) in the parafoveal region (P = 0.045 versus controls). Structural changes in HCQ patients without retinopathy were significantly associated with macular function as R2:R5 ring ratio of mfERG P1 amplitude was associated with INL (P = 0.002) and ONL (P = 0.044) thicknesses, and R3:R5 ring ratio of P1 amplitude was associated with ONL thickness (P = 0.004).ConclusionsOur results suggest that structural alterations secondary to HCQ toxicity may occur in the absence of clinically detectable retinopathy, and this may reflect in an impaired macular function.

Computer Vision Syndrome Prevalence and Ocular Sequelae among Medical Students: A University-Wide Study on a Marginalized Visual Security Issue

Introduction: This study aimed to discover and document the potential of visual and ocular sequelae of computer vision syndrome (CVS) among medical students. Methods: This cross-sectional case-control study was conducted on medical students (n=4030) of five universities in Egypt. All students completed a specially designed and validated CVS questionnaire survey (CVS-F3). Students with ≥5 CVS symptoms constituted a risk group (n=352), while students with 1-4 CVS symptoms constituted a low-symptoms group (n=3067). Students from the control and risk groups were examined using objective methods, such as visual acuity, subjective refraction, dry eye disease tests, and anterior segment and fundus examinations. Students who complained of visual blur underwent multifocal electroretinography mfERG examinations (mfERG group). Results: The CVS-F3 indicated that 84.8% of students had complaints that might be related to CVS, however, our ophthalmic examination group revealed only a 56% CVS prevalence rate. The most common single screen type used by 70.4% of students was the smartphone, and the most common complaint was headache (50.2%). Multivariate logistic regression analysis revealed that CVS was significantly associated with increased screen-hours, including &gt;2 screen-hours daily (odds ratio [OR], 2.48; P&lt;0.0001), &gt;2 screen-hours at night (OR, 1.79; P=0.003), and ≥3 screen-years (OR, 1.69; P=0.006). In the mfERG group, 37% demonstrated reduced amplitudes of mfERG rings and quadrants, indicating reduced foveal responses. Conclusion: CVS-questionnaires overestimate the true CVS prevalence and sequelae, which could be accurately detected by objective ophthalmic examination. Smartphones primarily caused CVS among students, with CVS severity increasing in correlation with shorter eye-to-screen distance and frequent use. Contact lens wearing doubled the risk of CVS development and augmented its severity. CVS might affect macular integrity with screen-induced foveal dysfunction. Clinical Trials Registration: PACTR201811618954630.

Multifocal Electroretinogram, Central Macula Thickness and Visual Acuity in Diabetic Macular Edema Following Intravitreal Injection of anti-VEGF

Introduction : Diabetic Retinopathy (DR) is one of the major cause of visual acuity deterioration in diabetic patients. The loss of central visual acuity in diabetic patients are mainly due to macula edema, which is found in 29% diabetic patients with the over 20 years duration of disease. The aim of this study is to evaluate and investigate the possible correlation among changes of visual acuity (VA), central macular thickness (CMT) using Spectral Domain Optical Coherence Tomography (SD-OCT). Electrophysiological responses using multifocal electroretinography (MfERG) in diabetic macular edema (DME) following intravitreal injection of bevacizumab.&#x0D; Methods: Single arm clinical trial. Thirty-three eyes of 33 DME patients (16 non-proliferative diabetic retinopathy and 17 non-high-risk proliferative diabetic retinopathy), receives intravitreal bevacizumab 1,25mg. All patients underwent complete ophthalmic examination including ETDRS VA testing, Sixty-one scaled hexagon MfERG and SD-OCT scan at baseline, 1-week and 1-month post-injection. Components of the first order kernel (N1, N2 and P1) in central 2o were measured.&#x0D; Result : MfERG showed reduced P1 amplitude (P&lt;0.05) at 1-week after injection followed by increased P1 amplitude (P&gt;0.05) at 1-month after treatment as compared to the baseline in all subjects. There was 19% improvement CMT and 0.2Logmar VA improvement in 1-month post-injection compared to the baseline (P&lt;005). This study showed no serious ocular adverse effects. There was no significant correlation between changes in visual acuity with changes in CMT or other MfERG parameters.&#x0D; Conclusion: Intravitreal injection bevacizumab resulting in improved VA, reduction in CMT and mild improvement in the MfERG responses. Although VA changes did not correlate with reduced CMT nor with improved responses of MfERG, the combined use of SD-OCT and MfERG may be used to evaluate macular function in DME patient with worsened visual acuity post anti-VEGF injection.