Efficacy and safety of intravitreal injections of conbercept for the treatment of idiopathic choroidal neovascularization

BACKGROUND

To determine the efficacy and safety of intravitreally injected conbercept, a vascular endothelial growth factor receptor fusion protein, for the treatment of idiopathic choroidal neovascularization (ICNV).

METHODS

This retrospective study analyzed outcomes in 40 patients (40 eyes) with ICNV who received intravitreal injections of conbercept 0.5 mg (0.05 ml) and were followed up for at least 12 months. All patients underwent full ophthalmic examinations, including best-corrected vision acuity (BCVA), intraocular pressure (IOP), slit-lamp examination, color fundus photography, optical coherence tomography angiography, multifocal electroretinogram, and fundus fluorescence angiography, if necessary, at baseline and after 1, 3, 6, and 12 months. BCVA, macular central retinal thickness (CRT), IOP, CNV blood flow area, thickness of the CNV-pigment epithelial detachment complex, thickness of the retinal nerve fiber layer (RNFL), and the first positive peak (P1) amplitude density in ring 1 before and after treatment were compared.

RESULTS

Mean baseline BCVA (logMAR), CRT, CNV blood flow area, and CNV-pigment epithelial detachment complex thickness were significantly lower 1, 3, 6, and 12 months after than before conbercept treatment (P < 0.05 each). IOP and baseline RNFL thickness were unaffected by conbercept treatment. P1 amplitude density was significantly higher 1, 3, 6, and 12 months after than before conbercept treatment (P < 0.05 each). None of the 40 eyes showed obvious ocular adverse reactions, such as endophthalmitis, glaucoma, cataract progression, and retinal detachment, and none of the patients experienced systemic adverse events, such as cardiovascular and cerebrovascular accidents.

CONCLUSIONS

Intravitreal injection of conbercept is beneficial to eyes with ICNV, inducing the recovery of macular structure and function and improving BCVA, while not damaging the neuroretina. Intravitreal conbercept is safe and effective for the treatment of ICNV.

Abnormalities of retinal function in type 2 diabetes mellitus patients without clinical diabetic retinopathy detected by multifocal electroretinogram

OBJECTIVE

To study the changes of retinal function in type 2 diabetes mellitus(DM) patients without apparently diabetic retinopathy via multifocal electroretinogram.

METHODS

Thirty-six type 2 DM patients (72 eyes) without visible diabetic retinopathy were selected as the experimental group, and thirty-five healthy subjects (70 eyes) were selected as the control group. All subjects were underwent multifocal electroretinogram (mf- ERG).

RESULTS

Compared with the control group, the implicit time delay of the P1 wave in the first ring, third ring, fourth ring, and fifth ring of the experimental group was significant (t = -3.154, p = 0.004, t = -8.21, p = 0.000, t = -3.067, p = 0.004, t = -4.443, p = 0.000, respectively). The implicit time of the N1 wave in the fourth- and fifth-ring were also significantly delayed compared with the control group (t = -3.549, p = 0.001, t = 2.961, p = 0.005, respectively). Compared with the control group, the implicit time of the P1 wave and N1 wave in the temporal region of the experimental group were delayed (t = -2.148, p = 0.037, t = -2.834, p = 0.007, respectively). There were no significant difference between the experimental group and the control group of the temporal area in the amplitude density of P1 wave, N1 wave. There was no difference in the implicit time and amplitude density of the N1 and P1 waves in the nasal region between the experimental group and the control group. The multifocal electroretinogram complex parameters showed better specificity and sensitivity in the diagnosis of diabetic retinopathy.

CONCLUSION

The multifocal electroretinogram can detect abnormal changes in the retina of type 2 DM patients without visible diabetic retinopathy. The multifocal electroretinogram complex parameter is a potential indicator for the early diagnosis of diabetic retinopathy.

Foveal avascular zone size and mfERG metrics in diabetes and prediabetes: a pilot study of the relationship between structure and function

PURPOSE

Previous studies have demonstrated functional and structural retinal changes in type 2 diabetes (T2DM). However, less is understood in prediabetes, which is an important precursor to T2DM. Here, we evaluate the microvasculature structure of the foveal avascular zone (FAZ) and how it is correlated with retinal function as measured by the multifocal electroretinogram (mfERG) across levels of glucose dysfunction to uncover how T2DM and prediabetes alter this structure-function relationship.

METHODS

33 subjects were included: 9 controls, 12 prediabetes, 12 T2DM with no retinopathy or edema. Subjects were aged 30-70 years, had BCVA of 20/25 or better, and had no confounding ocular conditions. Blood was collected via fingerstick to determine Hemoglobin A1c (HbA1c), which was used along with previous diagnosis, to determine study grouping. Optical coherence tomography angiography (OCTA) was used to analyze the FAZ area and was corrected for refractive error. FAZ area was measured by hand using the Heidelberg Spectralis software. mfERG (VERIS 6.3) metrics implicit time (IT) and amplitude were evaluated in the foveal region, macular region, and averaged over the posterior pole of the right eye. Regression analysis was performed between each study group parameter to determine relationships, and t tests with corrections were used to compare groups.

RESULTS

FAZ area (superficial plexus) was negatively correlated with mfERG posterior pole amplitude (p < 0.01, R2 = 0.30), foveal amp (p = 0.02 R2 = 0.17) and macular amplitude (p = 0.02 R2 = 0.18) across all 33 study subjects. FAZ and mfERG metrics were not significantly different between study groups in this cohort except for IT, which was more delayed in the diabetes group compared to other groups.

CONCLUSION

FAZ area is correlated with mfERG amplitudes but not IT. This suggests a link between the structural metrics and retinal function. Longitudinal follow-up work would be helpful to determine the timing of these changes in prediabetes.

The effect of COVID-19 on referral patterns for clinical electrophysiological testing

PURPOSE

To provide an overview of the effect that the COVID-19 pandemic has had on visual electrophysiology referral patterns and the subsequent effect this may have on patients.

METHODS

All electrodiagnostic tests performed at Kensington Vision and Research Centre, Toronto Canada, in a 3-month period prior to the COVID-19 pandemic (1 September 2019 to 30 November 2019) were compared to a 3-month period after the start of the COVID-19 pandemic (1 September 2021 to 30 November 2021).

RESULTS

A total of 502 patients had electrodiagnostic testing carried out in the designated time periods: 292 in the time period prior to the COVID-19 pandemic and 210 patients after. There was a significant change in the reason for referral in patients pre-COVID compared to post-COVID (p = 0.004). There was a 43% reduction in referrals for drug monitoring, 25% reduction for hereditary pathology and a 27% increase in acquired pathology after the start of the COVID-19 pandemic compared to before.

CONCLUSIONS

There was a substantial decrease in the total number of patients referred after the start of the COVID-19 pandemic compared to pre-COVID with inherited retinal pathology and drug monitoring patients being 2 populations most affected by the disruption to healthcare services.

The relation of the multifocal electroretinographic response to macular layer volume

PURPOSE

To determine the association of the multifocal electroretinographic (mfERG) response amplitude with the volumes of the inner, postreceptor, and photoreceptor retinal layers in the region stimulated by each mfERG element.

METHODS

Sixteen healthy, young adult control subjects were studied. Each of the 103 hexagonal elements of the standard, scaled mfERG were aligned, where possible, with patches of retina imaged using optical coherence tomography. Stimuli falling on the fovea and on the optic nerve head were excluded. Linear mixed-effects modeling was then used to derive estimated coefficients (voltage/volume) for the mfERG response throughout the full 80 ms standard epoch. The resulting predicted response amplitudes originating in each layer were then compared to pharmacologically "dissected" mfERGs obtained from other studies in monkey eyes.

RESULTS

Across the duration of the response, the amplitude of the modeled contribution from (1) the inner retina was small-to-modest, (2) the postreceptor retina was larger and contained two prominent peaks, and (3) the photoreceptor response was the largest and most closely paralleled the overall (i.e., intact) response, including late-appearing oscillations. The significance of each layer's contribution was greatest when the absolute amplitude of that layer's response was largest. The contribution of the inner retina was maximally significant in the interval between the prominent troughs and peaks of the intact response. The contributions of the postreceptor and photoreceptor responses were maximally significant at the prominent troughs and peaks of the intact response.

CONCLUSIONS

The results of the model were in good overall agreement with previous interpretations of the cellular contributions to the mfERG. There was also fair agreement with pharmacologically dissected monkey mfERG responses. Thus, the estimations of the contributions of the retinal layers to the mfERG so produced appeared plausible.

Analysis on short-term change of macular function and the correlates after intravitreal conbercept for CRVO-ME

Aim

To study the short-term change of macular function and the correlates after intravitreal conbercept for CRVO-ME.

Study design

Prospective, clinical study.

Methods

Twenty Three patients(23 eyes) were recruited, who were non-ischemia central retinal vein occlusion diagnosed by FFA (fundus fluorescein angiography) and treated with intravitreal conbercept for macular edema, best – corrected visual acuity ( BCVA), central macular thickness(CMT), amplitude density of P1 wave and implicit time of P1,N1 wave from ring 1 and ring 2 of mf-ERG were measured before and 1 week、2 month after treatment.

Results

Compared to the baseline, BCVA、CMT、amplitude density of P1 wave and implicit time of P1,N1 wave from ring 1 and ring 2 were greatly improved at 1 W、2 M after treatment; better results were gained at 2 M compared to 1 W; Pearson correlation analysis shows no significantly correlation between the improvement of mf-ERG with the change of BCVA、CMT.

Conclusion

The BCVA、the structure and the function of macular were greatly improved after intravitreal conbercept for central retinal vein occlusion induced macular edema; however no significantly correlation between the improvement of the function of macular with the strcture of macular and BCVA.

Vogt-Koyanagi-Harada syndrome-like uveitis after nivolumab administration as a treatment for ovarian cancer

PURPOSE

To report a case of Vogt-Koyanagi-Harada (VKH) syndrome-like posterior uveitis after nivolumab administration to treat an ovarian cancer with an electrophysiological finding. A 61-year-old woman with ovarian cancer (stage 3A) and salpingo-oophorectomy surgery history visited the clinic complaining of blurred vision in both eyes. She had been enrolled a clinical trial using nivolumab in patients with ovarian cancer. She received four cycles of nivolumab administration and experienced blurred vision one week before the initial visit. There was no remarkable finding in the anterior segment and the vitreous body. Multiple subretinal fluid accumulations and serous retinal detachment were identified on the posterior pole. Subretinal fluid with choroidal folding was noted in optical coherence tomography, and multiple leakage points were also observed in wide-field fundus fluorescein angiography. Therefore, intravenous high-dose steroid pulse therapy was applied under the diagnosis of VKH syndrome-like posterior uveitis induced by an immunotherapy agent. After steroid therapy, the subretinal fluid was absorbed completely, and the patient's visual acuity was recovered to the normal range. The amplitudes in the multifocal electroretinogram were also restored after the treatment.

CONCLUSION

Nivolumab is a human IgG4 monoclonal antibody and an immune checkpoint inhibitor. It is associated with the upregulation of T-cell activity by interfering with the interaction between the programmed death-1 (PD-1) receptor and the PD-ligand. Targeted therapy using immunotherapy agents has been widely used for malignant melanoma, lung cancer, renal cell carcinoma, and other cancers. However, immunotherapy agents such as nivolumab can induce autoimmune-related adverse events including uveitis. This report suggests that VKH syndrome-like posterior uveitis could be induced by nivolumab administration for an ovarian cancer treatment, which was resolved by steroid pulse therapy.

Infliximab recovers central cone dysfunction with normal fundus in a patient with ulcerative colitis

Purpose

To report the efficacy of anti-tumor necrosis factor α (anti-TNFα) on autoimmune-mediated macular cone dysfunction in a Japanese woman with ulcerative colitis (UC).

Observations

A 41-year-old woman presented with bilateral visual acuity loss and photophobia. She suffered from UC, and had been treated with prednisolone and 5-aminosalicylate since age 37. Although fundus photographs and optic coherence tomography images were unremarkable, electroretinograms (ERGs) were abnormal. A full-field electroretinogram (full-field ERG) revealed mildly decreased cone responses and oscillatory potential responses bilaterally. Importantly, focal-macular ERG (fmERG) and a multifocal electroretinogram (mfERG) revealed severe macular cone dysfunction in both eyes. Infliximab, a chimeric monoclonal anti-TNFα antibody, was administrated to treat recurrent abdominal symptoms and continued at 8-week intervals. Almost 6 months after infliximab therapy, the mfERG response (especially in the central retina), the fmERG response, and visual acuity recovered bilaterally. Abdominal symptoms also improved after infliximab therapy.

Conclusions and importance

Bilateral cone dysfunction with normal fundus were observed in a UC patient, resulting in loss of visual acuity and photophobia. This retinopathy may have been caused by an autoimmune mechanism, such as an autoimmune retinopathy or acute zonal occult outer retinopathy, which is most identifiable by ERG changes. This is the first report demonstrating the efficacy of infliximab in autoimmune retinal dysfunction.

Altered central vision and amacrine cells dysfunction as marker of hypodopaminergic activity in treated patients with schizophrenia

BACKGROUND

Retinal dysfunction is widely documented in schizophrenia using flash (fERG) and pattern electroretinograms (PERG), but the role of dopamine transmission has seldom been explored.

METHODS

We explored the role of dopamine transmission by evaluating the spatial location of retinal anomalies using multifocal ERG (mfERG) in photopic condition and the oscillatory potentials (OPs) extracted from fERG measured in scotopic condition in 29 patients with schizophrenia and 29 healthy controls.

RESULTS

With the mfERG, our main results revealed reduced amplitudes in the center of the retina: P1 (p < .005) and N2 amplitudes (p < .01) in the <2° region, N1 (p < .0005) and P1 amplitudes (p < .001) in the 2-5° region and P1 amplitude (p < .05) in the 5-10° region. For OPs, our results showed a decrease in the O1 (p < .005), O2 (p < .005), O3 (p < .05) and overall O1, O2, O3 index amplitudes (p < .005) in patients with schizophrenia.

CONCLUSIONS

Both the central location of retinal dysfunctions of the mfERG and OPs results could reflect a hypodopaminergic effect in patients with schizophrenia. In future studies, OPs should be considered as a measure to evaluate the hypodopaminergy in patients.

Diagnosis of multiple sclerosis using multifocal ERG data feature fusion

The purpose of this paper is to implement a computer-aided diagnosis (CAD) system for multiple sclerosis (MS) based on analysing the outer retina as assessed by multifocal electroretinograms (mfERGs). MfERG recordings taken with the RETI-port/scan 21 (Roland Consult) device from 15 eyes of patients diagnosed with incipient relapsing-remitting MS and without prior optic neuritis, and from 6 eyes of control subjects, are selected. The mfERG recordings are grouped (whole macular visual field, five rings, and four quadrants). For each group, the correlation with a normative database of adaptively filtered signals, based on empirical model decomposition (EMD) and three features from the continuous wavelet transform (CWT) domain, are obtained. Of the initial 40 features, the 4 most relevant are selected in two stages: a) using a filter method and b) using a wrapper-feature selection method. The Support Vector Machine (SVM) is used as a classifier. With the optimal CAD configuration, a Matthews correlation coefficient value of 0.89 (accuracy = 0.95, specificity = 1.0 and sensitivity = 0.93) is obtained. This study identified an outer retina dysfunction in patients with recent MS by analysing the outer retina responses in the mfERG and employing an SVM as a classifier. In conclusion, a promising new electrophysiological-biomarker method based on feature fusion for MS diagnosis was identified.

Removing mains interference from the mfERG by applying a post-processing digital notch filter: for the good or the bad?

Purpose

Ideally, the multifocal electroretinogram (mfERG) is recorded without noticeable intrusion of mains interference. However, sometimes contamination is difficult to avoid. A post-processing digital notch filter can help to recover the retinal response even in severe cases of mains interference. While a digital filter can be designed to have little to no impact on peak times, filtering out mains interference also removes the retinal signal content of the same frequency, which may result in a change of amplitude. The present study addressed this issue in the standard first order kernel mfERG.

Methods

In 24 recordings from routine exams with no perceivable mains interference, the effects of 50-Hz and 60-Hz non-causal digital notch filters on amplitude and peak time were assessed. Furthermore, the effect of filtering on contaminated traces was demonstrated and simulated mains interference was used to provide an example of nonlinear superposition of retinal signal and mains interference.

Results

mfERG amplitudes were reduced by 0%–15% (median 6%) with the 50-Hz filter and remained virtually unaffected with the 60-Hz filter. Simulations illustrate that spurious high-frequency components can occur in the filtered signal if a strongly contaminated signal is clipped due to a limited input range of the analog-to-digital converter.

Conclusion

The application of a 50-Hz digital notch filter to mfERG traces causes a mild amplitude reduction which will not normally affect the clinical interpretation of the data. The situation is even more favorable with a 60-Hz digital notch filter. Caution is necessary if the assumption of linear additivity of retinal signal and mains interference is violated.

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

Purpose

Multifocal 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.

Methods

Patients 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.

Results

In 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.

Conclusions

In 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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10633-021-09858-4.

Decreased Retinal Sensitivity Overlying Choroidal Nevi

Purpose

To report retinal function findings on the choroidal nevus.

Methods

Prospective descriptive case series of 7 patients (n = 7 eyes) presenting a melanocytic choroidal lesion consistent with choroidal nevus and no other ocular disease. Baseline evaluation included measurement of best-corrected visual acuity (BCVA), color and near-infrared fundus pictures, and spectral-domain OCT (Heidelberg Engineering). Retinal function was tested with microperimetry (MAIA; CenterVUE, Padova) using a standard grid (µP1) and a linear grid (µP2) that distribute test points on retinal areas that overlaid the choroidal lesion as well as lesion-free areas equidistantly to the fovea in 3 parallel lines. mfERG was performed following the International Society for Clinical Electrophysiology of Vision (ISCEV) recommendation using a 61-hexyagon protocol.

Results

BCVA was 20/25 (0.1 logMAR) or better in all 7 eyes. Microperimetry showed central stable fixation on all eyes, with mean ± SE sensitivity threshold significantly decreased on retinal areas overlaying the lesions (µP1): 21.8 ± 0.6 dB versus 25.2 ± 0.9 dB on nonaffected retinal areas (p < 0.001). Sensitivity was also decreased on µP2: 23.7 ± 0.2 dB for areas overlying the nevi and 25.7 ± 0.3 dB for the nonaffected retina (p < 0.001). mfERG responses showed no focal amplitude or implicit-time changes on the retina in the topographical region corresponding to the nevus for all patients.

Conclusion

Our results indicate that choroidal nevi may cause significant retinal sensitivity impairment, as shown by microperimetry, but preserved mfERG response indicates that the retinal function may be only partially impaired.

Assessment of Macular Function by Multifocal Electroretinogram in Patients with Multiple Sclerosis Treated with Fingolimod

Introduction

This study aimed to evaluate whether treatment with fingolimod (FTY) may induce functional changes on the macular pre-ganglionic retinal elements in patients affected by relapsing–remitting multiple sclerosis (RR-MS) without optic neuritis (ON).

Methods

This case–control observational and retrospective study assessed multifocal electroretinogram (mfERG) responses from 35 healthy controls (mean age 43.58 ± 5.76 years), 41 patients with RR-MS without ON (mean age 40.64 ± 4.83 years, MS-noFTY group), and from 21 patients with RR-MS without ON (mean age 42.38 ± 12.34 years) and treated with fingolimod (Gilenya®, Novartis Europharm, 0.5 mg/day) (MS-FTY group). MfERG N1 and P1 implicit times (ITs), and N1–P1 response amplitude densities (RADs) were measured from concentric rings (R) with increasing foveal eccentricity: 0–5° (R1), 5–10° (R2), 10–15° (R3), 15–20° (R4), 20–25° (R5). We considered R1 and R2 as “central macular areas” and R3, R4 and R5 as “more eccentric retinal areas”. In the MS-FTY group, mfERG recordings were performed between 6 and 12 months (mean 7.2 ± 1.5 months) from the start of FTY.

Results

In the MS-FTY group, the mean values of mfERG N1 and P1 ITs and RADs detected in both central macular areas (R1 and R2) and in more eccentric retinal areas (R3, R4 and R5) were not significantly different (p > 0.01) with respect to those of control and MS-noFTY groups.

Conclusions

Our mfERG results suggest that the chronic use of FTY does not induce a dysfunction of pre-ganglionic retinal elements located in the 0–25° of central retina. Since FTY does not cause any retinal functional abnormality, we suggest that FTY treatment could not produce any toxic effect on pre-ganglionic retinal elements even in the absence of macular oedema.

Citicoline and Vitamin B12 Eye Drops in Type 1 Diabetes: Results of a 36-Month Pilot Study Evaluating Macular Electrophysiological Changes

Introduction

Our aim was to evaluate the effects of 36 months of treatment with citicoline and vitamin B₁₂ eye drops on macular function in patients with type 1 diabetes (DM1) with mild signs of non-proliferative diabetic retinopathy (NPDR).

Methods

A prospective, randomized, interventional, monocentric, double-masked study was conducted. Twenty patients with DM1 were enrolled and randomly divided into two groups: the DC group (10 patients; mean age ± standard deviation 46.86 ± 8.78 years) in which one eye of each patient was treated with citicoline and vitamin B₁₂ eye drops (OMK2^®, Omikron Italia srl, Italy, one drop thrice daily) for a period of 36 months; the DP group (10 patients; mean age ± standard deviation 47.89 ± 7.74 years) in which one eye of each patient was treated with placebo (eye drops containing hypromellose 0.3%, one drop thrice daily) for a period of 36 months. A total of 18 eyes (10 from the DP and 8 from the DC group, respectively) completed the study. In both groups, multifocal electroretinogram (mfERG) recordings were assessed at baseline and after 36 months. In mfERG analysis, the N1–P1 response amplitude density (RAD) evaluated in the 0–2.5° (ring 1), in the 2.5–5° (ring 2), in the 5–10° (ring 3), and in the 0–10° (ring 1 + ring 2 + ring 3) were considered.

Results

With respect to baseline, after 36 months of follow-up, the mfERG RADs recorded in R1, R2, R3, and R1 + R2 + R3 were significantly increased (i.e., R1 + R2 + R3 RAD from 21.552 ± 2.522 nV/degree² at baseline to 26.912 ± 2.850 nV/degree² at 36 months) in DC eyes, whereas in DP eyes they were significantly reduced (i.e., R1 + R2 + R3 RAD from 21.033 ± 3.574 nV/degree² at baseline to 16.151 ± 3.571 nV/degree² at 36 months).

Conclusions

This study indicates that patients with NPDR treated with citicoline and vitamin B₁₂ eye drops for a 36-month period achieved an improvement of the macular bioelectrical responses detectable by mfERG recordings. By contrast, during the same period of follow-up, patients with NPDR treated with placebo showed a worsening of the macular function.

Electrophysiological Monitoring of Focal and Entire Retinal Function during Treatment with Intravitreal Methotrexate for Intraocular Lymphoma

We describe the electroretinographic findings of a case of primary intraocular lymphoma (PIOL) wherein the patient received intravitreal injections of methotrexate (ivMTX). A 62-year-old man developed blurred vision and complained of decreased visual acuity (VA) in his right eye. Fundus examination showed vitreous opacity and multiple subretinal yellowish lesions. Optical coherence tomography (OCT) revealed subretinal and intraretinal infiltrations. The full-field electroretinogram (ffERG) showed subnormal combined rod-cone response and multifocal electroretinogram (mfERG) recorded using skin electrodes showed severe attenuation of the response compared with the other eye. Pars prana vitrectomy, phacoemulsification, and lens implantation were performed to remove the opacity, and vitreous biopsy revealed a high ratio of interleukin 10–6 (76.0). There was no systemic malignant lesion, and the patient was diagnosed with PIOL. Treatment with ivMTX (400 μg/0.1 mL) was started. One month later, the intraretinal infiltration had disappeared, and mfERG revealed recovery of the response density from the central area. Two months later, OCT showed recovery of the foveal ellipsoid and interdigitation zones, and VA recovered to 20/17; mfERG showed maintenance of macular function. However, the amplitude of a- and b-waves in the ffERG gradually decreased. Macular function recovered, but there was also a decrease in total retinal function. mfERG and ffERG recorded using skin electrodes were useful in monitoring macular and entire retinal function with repeated examinations and showed recovery and maintenance of macular function in a case of PIOL treated with ivMTX.

Organic visual loss measured by kinetic perimetry and retinal electrophysiology in children with functional amblyopia

PURPOSE

To demonstrate an organic (retinal) amblyogenic defect in functional amblyopes not responding to treatment.

METHODS

Twenty-four children (Mean age: 5.9 ± 1.8 years; range: 4-10 years) with functional amblyopia were recruited for this study. All these children underwent complete ophthalmic and orthoptic evaluation. In addition, Kinetic Goldman Visual Fields (KGVF), Spectral Domain Optical Coherence Tomography (SD-OCT), full field flash electroretinograms (ffERG) and multifocal electroretinograms (mfERG) were also performed. Ratios were subsequently derived by comparing the amplitudes obtained from the amblyopic eye (AE) to the good eye (GE) for the a- and b-waves of the ffERG, as well as for the ring analysis of the mfERG.

RESULTS

KGVF showed a central scotoma of varying size (3°-7°) and density (absolute to relative), with increasing target size in 14/24 patients whose best post-treatment vision in the AE ranged from 20/100 to 20/40. The scotoma decreased in size and density with improving vision until a plateau of recovery was reached. The remaining 10/24 patients with a vision ≥ 20/30 showed no scotoma. SD-OCT showed no significant difference between the AE and GE. ffERG and mfERG were obtained in 18/24 patients. The ffERG AE/GE ratio was abnormal in 7 patients, 5 of which had large scotomas on KGVF. The mfERG ring 1 AE/GE ratio was significantly (p < .05) attenuated in 9/18 patients out of which 3 were no longer amblyopic. However, there was no significant difference (p > .05) in ring 1 AE/GE amplitude ratio between those who achieved 20/50-20/40 (.81 ± .26) and those with ≥ 20/25(.86 ± .25).

CONCLUSIONS

The combined findings of central scotoma on KGVF and mfERG anomalies in patients who did not achieve optimal vision with treatment suggest an underlying organic defect impairing macular function.

ISCEV standard for clinical multifocal electroretinography (mfERG) (2021 update)

The multifocal electroretinogram (mfERG) is an electrophysiological test that allows the function of multiple discrete areas of the retina to be tested simultaneously. This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV), presents an updated and revised ISCEV standard for clinical mfERG and defines minimum protocols for basic clinical mfERG recording and reporting so that responses can be recognized and compared from different laboratories worldwide. The major changes compared with the previous mfERG standard relate to the minimum length of m-sequences used for recording, reporting of results and a change in document format, to be more consistent with other ISCEV standards.

Correlations among metamorphopsia test scores, optical coherence tomography findings and multifocal electroretinogram responses in epiretinal membrane patients

PURPOSE

To quantify metamorphopsia with a novel objective method in patients with epiretinal membrane (ERM) and to compare the relationships among metamorphopsia scores, spectral-domain optical coherence tomography (OCT) findings, and multifocal electroretinogram (mfERG) results.

METHODS

This study included 52 eyes of 52 patients with idiopathic ERM who underwent comprehensive ophthalmologic examinations, including measurement of best-corrected visual acuity (BCVA), OCT, and mfERG. The degree of metamorphopsia was quantified using MonPack One® (Metrovision, Perenchies, France). On the topographic map of the early treatment diabetic retinopathy (ETDRS) grid, retinal thickness in the central, superior, inferior, nasal, and temporal subfields were measured, and metamorphopsia scores for each corresponding subfield were also obtained. The amplitudes and implicit times of mERG were elicited from each subfield. Then, the correlations among metamorphopsia scores, OCT findings, and mfERG responses were analyzed.

RESULTS

The mean age of the patients was 65.3 ± 18.5 y, and the average metamorphopsia score of the individual subfields was 2.03 ± 1.18. Initial BCVA was 0.50 ± 0.12 logMAR, but there was no significant correlation between metamorphopsia scores and BCVA. The metamorphopsia scores from the central subfields showed significant correlations with central retinal thickness (CRT) (p = 0.001). The mean metamorphopsia scores in the central subfield showed a significant relationship with the mean N1 and P1 amplitudes (p = 0.001, p = 0.048, respectively), while no relationship was observed between metamorphopsia scores and mfERG amplitudes in other subfields.

CONCLUSIONS

The degree of metamorphopsia in patients with ERM could be objectively quantified in each subfield using a novel metamorphopsia test. The metamorphopsia scores were significantly correlated with retinal thickness, especially at the central subfields, and the scores in the central subfields were significantly correlated with the N1 and P1 amplitudes of mfERG. Thus, the metamorphopsia test can be a useful method to evaluate metamorphopsia symptoms for patients with ERM.

Adaptive optics ophthalmoscopy, multifocal ERG and OCTA in unique case of suspected torpedo maculopathy presenting with vitelliform lesion

Purpose

To report the case of a ten-year old girl with torpedo maculopathy with a complete vitelliform lesion and describe associated optical coherence tomography (OCT), OCT angiography (OCTA), multifocal electroretinogram (ERG) and adaptive optics ophthalmoscopy (AOO) imaging of the lesion.

Observations

An asymptomatic ten-year old girl with visual acuity of 20/15 OU was referred for evaluation of possible Best's disease of her left eye. The unilaterality, location, and shape of the lesion was consistent with torpedo maculopathy. OCT and autofluorescence (AF) revealed that the entire lesion was composed of subretinal hyperreflective material that was hyperautofluorescent, consistent with vitelliform material. Within the boundary of the lesion, OCTA showed reduced choriocapillaris density while adjacent to the lesion, the choriocapillaris density was slightly increased. Microperimetry demonstrated normal sensitivity in both eyes, electrooculograms (EOG) were normal and multifocal ERG showed symmetrical mildly supernormal amplitudes. Additionally, AOO demonstrated that nasal to the lesion there were clusters of hyper-reflective areas, and immediately adjacent to the lesion cones were poorly resolved. However, there was a return to more normal photoreceptor architecture outside of the lesion.

Conclusions and Importance

Torpedo maculopathy lesions typically present with outer retinal attenuation and retinal pigmented epithelium (RPE) atrophy. Vitelliform material was recently observed for the first time in association with Torpedo maculopathy in a case report that described small vitelliform material at the periphery of the lesion. We report the second case of torpedo maculopathy associated with a vitelliform lesion and the first description of a torpedo lesion composed fully of presumed vitelliform material. We also describe findings of OCTA, multifocal ERG and AOO imaging in torpedo maculopathy with vitelliform lesion.

Functional assessment of early retinal changes in diabetic patients without clinical retinopathy using multifocal electroretinogram

BACKGROUND

We aimed to assess early retinal changes in diabetic subjects without clinical retinopathy using multifocal electroretinogram (mfERG).

METHODS

Twenty eyes of 20 diabetic subjects type 2 without retinopathy and 20 eyes of 20 healthy controls of the same age and sex were eligible for our study and underwent mfERG. MfERG responses were recorded; N1-P1 amplitude and P1 implicit time of the 5 rings recorded were measured and analyzed.

RESULTS

The reduction in N1-P1 amplitude and the delay in P1-implicit time in type 2 diabetic subjects were statistically significant in most of the assessed rings compared to controls (p <  0.001). Moreover, N1-P1 amplitude was negatively correlated with diabetes duration. However, there was a positive correlation between P1-implicit time and diabetes duration in type 2 diabetic subjects in four out of five rings (p <  0.001).

CONCLUSIONS

Our study showed reduced mfERG N1-P1 amplitude and delayed P1-implicit time indiabetic patients without retinopathy compared to normal controls. Implicit time andamplitude were significantly affected by diabetes duration. These results propose a valuable role of mfERG in evaluating the expected neuroretinal dysfunction before the clinical development of diabetic retinopathy. Early detection of functional abnormalities indicates that the patients need more tight medical control of diabetes. More well-designed studies are needed to assert upon these results.

Optical Coherence Tomography Angiography and Multifocal Electroretinogram Findings in Paracentral Acute Middle Maculopathy

Paracentral acute middle maculopathy (PAMM) is an optical coherence tomography (OCT) finding seen in patients with retinal capillary ischemia. In this case report, we present a case of PAMM after a transient central retinal artery occlusion and the multifocal electroretinogram (mfERG) and other multimodal imaging findings. Clinical examination, OCT angiography, OCT en face, fluorescein angiography, and visual fields were performed at the baseline and follow-up examinations. As a result, we identified in this PAMM case evidence of hypoperfusion in both the choriocapillaris as well as the deep capillary plexus. To the best of our knowledge, the involvement of choriocapillaris has not been reported previously in the literature. Moreover, we concluded that mfERG constitutes a useful investigation in PAMM and this is the first mfERG findings to be presented for a PAMM case specifically.

Spatial localization of retinal anomalies in regular cannabis users: The relevance of the multifocal electroretinogram

Widely used in industrialized countries, cannabis is a neuromodulator substance. The cannabinoid system is present at critical stages of retinal processing. We have recently shown a delay in bipolar and ganglion cell responses in regular cannabis users, as observed using flash (fERG) and pattern (PERG) electroretinogram. Although the results obtained during these tests provide information about global retinal responses, they do not give any indication about the spatial localization of the anomalies that were detected. The latter may be analyzed, however, by means of multifocal electroretinogram (mfERG). We recorded the mfERG responses in 49 regular cannabis users and 21 healthy subjects. The amplitudes and implicit times of the mfERG N1, P1 and N2 waves were recorded. The results showed that in regular cannabis users: in the <2° region, a significant increase in the N2 implicit time (p = 0.037); in the 2-5° region, a significant increase in the N2 (p = 0.018) and P1 (p = 0.046) implicit times; in the 5-10° region, a significant increase in the P1 (p = 0.006) and N1 (p = 0.034) implicit times; and in the 10-15° region, a significant increase in the P1 implicit time (p = 0.014). An isolated decrease in the N1 amplitude in the 2-5° region (p = 0.044) was also found. This indicates that there is a delay in the transmission of visual information from the central retina to the near periphery in cannabis users suggesting potential alterations in precise and color vision.

Ring analysis of multifocal oscillatory potentials (mfOPs) in cCSNB suggests near-normal ON-OFF pathways at the fovea only

PURPOSE

To investigate the center-periphery distribution of ON and OFF retinal responses in complete congenital stationary night blindness (cCSNB).

METHODS

Photopic full-field flash ERGs (photopic ffERGs) and OPs (photopic ffOPs) and slow m-sequence (to enhance OP prominence) mfERGs (and filtered mfOPs) evoked by a 37 hexagon stimulus array were recorded from normal subjects and cCSNB patients. Discrete wavelet transform (DWT) analysis of photopic ffERGs and mfERGs was also performed in order to assess the contribution of the ON and OFF retinal pathways (i.e., OFF-to-ON ratio) in both cohorts.

RESULTS

As expected, the photopic ffERG (and ffOPs) responses in cCSNB were devoid of the first two of the three OPs (i.e., OP2 and OP3 and OP4) normally seen on the ascending limb of the b-wave. A similar finding was also noted in the mfERGs (and mfOPs) of ring 4. In contrast, the mfERGs (and mfOPs) of ring 1 included all three OPs. DWT analysis revealed that while in normal subjects, the OFF-to-ON ratio of mfERGs slightly increased from rings 1 to 4 (from 0.61 ± 0.03 to 0.78 ± 0.04; p < 0.05; median: from 0.62 to 0.79; p < 0.05), in cCSNB this ratio increased significantly more [from 0.73 ± 0.13 (ring 1) to 1.18 ± 0.17 (ring 4); p < 0.05; median: 0.78 to 1.22; p < 0.05], hence from a normal ON-dominated ratio (central ring) to an OFF-dominated ratio (peripheral ring).

CONCLUSIONS

Our results show a clear discrepancy of ON and OFF mfOP components in cCSNB. Responses originating from the most central ring (i.e., ring 1) disclosed a near-normal electrophysiological contribution (as revealed with the presence of OP2, OP3 and OP4 as well as with the DWT OFF-to-ON ratio) of the retinal ON and OFF pathways in mfERG (and mfOPs) responses compared to responses from the more peripheral ring (and ffOP) which are devoid of the ON OPs (i.e., OP2 and OP3).

Topographic correlation between multifocal electroretinography, microperimetry, and spectral-domain optical coherence tomography of the macula in patients with birdshot chorioretinopathy

PURPOSE

To correlate the findings of retinal function with multifocal electroretinogram (mfERG), microperimetry (MP), and structural assessments with spectral-domain optical coherence tomography (SD-OCT) in topographically corresponding areas of the macula of patients with birdshot chorioretinopathy (BSCR).

METHODS

Patients diagnosed with BSCR by clinical and imaging findings were included in the study. The mfERG was performed using 61 hexagon stimulus patterns grouped into 5 rings (Diagnosys Inc., USA). Individual responses [N1-P1 amplitudes in nanovolt (NV)/degree² and P1 implicit time in milliseconds (msec)] for each hexagon in the central 3 rings (R1, 0°-2.3°; R2,2.3°-7.7°; and R3, 7.7°-12°) were obtained (19 hexagons). MP examination consisted of Polar 3-12° test with 28 points in 3 concentric rings with diameters of approximately 2.3°, 6.6°, and 11.1° from the foveal center. SD-OCT was performed using macular scans of 20° × 20°. The retinal sensitivity values on MP and thickness values of retinal layers were correlated with the responses on the mfERG for each topographically correlated hexagon.

RESULTS

Sixteen eyes of eight patients were included in the study (mean age, 59.87 ± 10.01 years; range, 41-73 years). The amplitudes and the implicit times on mfERG and retinal sensitivities on MP were decreased for each of the 19 hexagons. Considering retinotopically matched points, there was correlation between the retinal sensitivities and mfERG implicit times and response amplitudes in all three rings. The thickness of the retinal pigment epithelium showed modest correlation with the mfERG parameters (ρ = 0.29; p = 0.04). The structural changes on SD-OCT, such as IS-OS disruption, were associated with changes in the mfERG trace arrays.

CONCLUSIONS

The structural and functional assessments in retinae of eyes with BSCR suggest that each imaging tool may be capturing unique aspects of retinal dysfunction. Multimodal imaging may allow detailed analyses of retinal damage at various corresponding loci. These findings are important when considering the use of these techniques in BSCR.

Identification of clusters in multifocal electrophysiology recordings to maximize discriminant capacity (patients vs. control subjects)

PURPOSE

To propose a new method of identifying clusters in multifocal electrophysiology (multifocal electroretinogram: mfERG; multifocal visual-evoked potential: mfVEP) that conserve the maximum capacity to discriminate between patients and control subjects.

METHODS

The theoretical framework proposed creates arbitrary N-size clusters of sectors. The capacity to discriminate between patients and control subjects is assessed by analysing the area under the receiver operator characteristic curve (AUC). As proof of concept, the method is validated using mfERG recordings taken from both eyes of control subjects (n = 6) and from patients with multiple sclerosis (n = 15).

RESULTS

Considering the amplitude of wave P1 as the analysis parameter, the maximum value of AUC = 0.7042 is obtained with N = 9 sectors. Taking into account the AUC of the amplitudes and latencies of waves N1 and P1, the maximum value of the AUC = 0.6917 with N = 8 clustered sectors. The greatest discriminant capacity is obtained by analysing the latency of wave P1: AUC = 0.8854 with a cluster of N = 12 sectors.

CONCLUSION

This paper demonstrates the effectiveness of a method able to determine the arbitrary clustering of multifocal responses that possesses the greatest capacity to discriminate between control subjects and patients when applied to the visual field of mfERG or mfVEP recordings. The method may prove helpful in diagnosing any disease that is identifiable in patients' mfERG or mfVEP recordings and is extensible to other clinical tests, such as optical coherence tomography.

Multifocal electroretinogram in eyes with intravitreal silicone oil and changes following silicone oil removal

PURPOSE

To determine the effect of intravitreal silicone oil (SO) on multifocal electroretinogram (mfERG) and the changes in mfERG following SO removal.

METHODS

Twelve eyes of 12 patients with SO in vitreous cavity with corrected distance visual acuity (CDVA) > 20/200 were prospectively enrolled as cases over a period from July 2016 to June 2018. The fellow normal eyes served as control. The eyes were evaluated with P1 and N1 wave amplitude and implicit time on mfERG at baseline, 1 and 4 weeks after SO removal.

RESULTS

The mean age was 44.9 ± 18.9 (range 18-74) years. The indication for SO injection was retinal detachment (n = 9, three macula-on eyes, six macula-off eyes) and endophthalmitis (n = 3). The median (range) LogMAR CDVA at baseline was 0.54 (0.18-0.78) in cases and did not change post-SO removal (p = 0.29). There was a significant decrease in average P1 and N1 wave amplitude (p = 0.0001 and 0.0001, respectively) and delay in average P1 and N1 wave implicit time (p = 0.0002 and 0.021, respectively) in cases as compared to controls. The macular status and duration of SO tamponade did not have a significant correlation with mfERG parameters. There was a significant increase in average P1 and N1 wave amplitude (p = 0.009 and 0.003, respectively) at 1 week following SO removal but no change in average P1 and N1 wave implicit time (p = 0.41 and 0.37, respectively).

CONCLUSION

mfERG may be reliably performed for the assessment of macular function in SO-filled eyes. Intravitreal SO exerts an insulating effect on the density of the electric potentials.

Retinal dysfunction in a presymptomatic patient with Huntington's disease

PURPOSE

Huntington's disease (HD) is an autosomal dominant, neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and psychiatric disturbances. Studies have shown retinal abnormalities in patients and mouse models with HD; however, to our knowledge, no prior research papers evaluated retinal structure and function in a presymptomatic patient with HD. The aim of this report is to present a case of retinal dysfunction in a presymptomatic patient with HD.

METHODS

We investigated retinal structure and function in a 25-year-old male who tested positive for the gene that causes HD, but did not have any symptoms normally associated with HD. Vision and ocular testing included a comprehensive dilated ophthalmic examination, 24-2 full-threshold Humphrey visual field, spectral-domain optical coherence tomography (SD-OCT), fundus photography, full-field electroretinogram (ERG), and multifocal electroretinogram (mfERG).

RESULTS

Visual electrophysiology testing showed rod and cone functional anomalies in both eyes. Full-field ERG amplitudes were subnormal in both eyes for the dark-adapted (DA) 0.01 ERG, DA 3 ERG, DA 3 oscillatory potentials (OPs), DA 10 ERG, light-adapted (LA) 3 ERG, and LA 30 Hz flicker, but peak times for the six standard ERG responses were not significantly different from normals. mfERGs revealed functional anomalies of the central retina with attenuated P1 amplitudes for five of the six concentric rings in the right eye and all six rings in the left eye. mfERG P1 peak times were normal at all eccentricities. Dilated fundus examination, SD-OCT, and fundus photography were unremarkable in both eyes. The visual field was normal in the right eye, but there was a mild paracentral field defect in the left eye.

CONCLUSIONS

Our results illustrate that the ERG and mfERG detected early retinal dysfunction in a presymptomatic patient with HD consistent with electroretinogram findings in animal models of HD. However, our report was limited to one patient and additional studies are needed to verify whether the ERG and/or mfERG can uncover neural dysfunction before motor, behavioral, and cognitive abnormalities are discernible in patients with HD.

Pericentral hydroxychloroquine retinopathy in a Caucasian female

Purpose

To report a rare presentation of the pericentral pattern of hydroxychloroquine (HCQ) retinal toxicity in a Caucasian female.

Observations

The patient presented with 20 years of exposure to HCQ, at a daily dose of 5.2mg/kg of actual body weight, and manifested a pericentral-only phenotype of HCQ toxicity, as demonstrated with detailed structural and functional testing.

Conclusions and importance

Although rare, the pericentral pattern of HCQ toxicity may occur in Caucasian patients in the absence of paracentral changes.

Comparison between multifocal ERG and C-Scan SD-OCT ("en face" OCT) in patients with a suspicion of antimalarial retinal toxicity: preliminary results

PURPOSE

Pericentral visual field changes and disruption of the ellipsoid layer on spectral domain optical coherence tomography (SD-OCT) are the main features of antimalarial retinal toxicity. C-Scan OCT or "en face" enables a topographic frontal view of the changes observed within the different retinal layers in particular the ellipsoid layer. The aim of this prospective study was to compare multifocal ERG (mfERG) responses with the results of C-Scan OCT ("en face" OCT) in patients with abnormal visual field and to analyze relationships between the structural and functional abnormalities.

METHODS

In 354 consecutive patients screened for antimalarial toxicity between January 1, 2014 and December 31, 2016, central visual field, mfERG recording, C-Scan OCT and short-wavelength fundus autofluorescent imaging were performed.

RESULTS

Among the 17/354 patients with abnormal central visual field results, all presented with abnormalities on the mfERG at least in one eye. In 16/33 eyes, there was a good concordance between focal loss of the mfERG response and the disruption of the ellipsoid layer on C-Scan OCT. In one eye with characteristic changes in the ellipsoid layer on the C-Scan OCT, the mfERG was normal, whereas in three eyes the mfERG was abnormal in eyes with a normal C-Scan OCT.

CONCLUSIONS

The contribution of the C-Scan OCT changes remains difficult to establish as there is no strict concordance with the local ERG responses. Although C-Scan OCT technology provides a new approach in analyzing focal abnormalities in the photoreceptor-retinal pigment epithelium interface, the sensitivity of this method compared with mfERG and other tests (central visual field, B-Scan OCT) needs to be evaluated. This study is still ongoing on a larger cohort.

Ganglion cell layer segmentation and the two-flash multifocal electroretinogram improve structure function analysis in early glaucoma

Purpose

To improve structure-function analysis in primary open-angle glaucoma (POAG) by including the two-global flash multifocal electroretinogram (2F–mfERG) and macular ganglion cell layer segmentation.

Methods

Twenty-five glaucoma patients (six pre-perimetric (PPG), 19 POAG) and 16 controls underwent 2F–mfERG, optical coherence tomography (OCT), and standard automated perimetry (SAP). For 2F–mfERG, the root mean square was calculated for the focal flash response at 15–45 ms (DC) and the global flash responses at 45–75 ms (IC1) and 75–105 ms (IC2). For OCT, macular total thickness (mT) and ganglion cell-inner plexiform layer (GCIPL) thickness were analysed. Values from the central 10° and 15° of 2F-mfERG were compared to the corresponding areas from OCT and visual field.

Results

Both PPG and POAG had significantly lower mfERG responses in the central 10° and 15° than the control group. Of the glaucoma patients, 30.7% (three PPG, five POAG) showed central mfERG and GCIPL reduction without a SAP defect in the central 15 degrees. Four patients had a central SAP defect associated with a reduced GCIPL without any detectable dysfunction on mfERG. MfERG DC and IC2 were larger with increased mT (p ≤ 0.02), but GCIPL only related positively to IC2 (p = 0.027). SAP sensitivity also increased with thicker mT but not with GCIPL (p < 0.03 and p = 0.35). DC, IC2, and GCIPL could best differentiate glaucoma from control (AUC values: 0.897, 0.903, and 0.905).

Conclusions

Structure function analysis in glaucoma can be improved when the GCIPL thickness as well as the 2F–mfERG is included as these measures complement information obtained by SAP.

Multifocal electroretinography changes at the 1-year follow-up in a cohort of diabetic macular edema patients treated with ranibizumab

PURPOSE

To determine the changes in the multifocal electroretinogram (mfERG) at 1 year in a clinical series of diabetic macular edema (DME) patients treated with ranibizumab (RNBZ) using a pro re nata protocol.

METHODS

We analyzed a clinical series of 35 eyes of 35 patients with DME at baseline and after treating them with RNBZ over 1 year, in order to determine the change in the macular function, which was assessed by means of the response density and the implicit time of the first-order kernel (FOK) P1 wave of the mfERG at the foveola (R1), fovea (R2) and parafovea (R3). These electrophysiological parameters were studied taking into account different independent variables, such as DME type, degree of diabetic retinopathy (DR), level of preservation of both the ellipsoid zone (IS/OS) and the external limiting membrane (ELM) and changes in central retinal thickness (CRT) and total macular volume (TMV). We also studied the relationship between the response density and the best-corrected visual acuity (BCVA).

RESULTS

Eyes with cystic and spongiform DME showed better response density with respect to the serous type (p < 0.001) at baseline. Similarly, eyes with high IS/OS and ELM preservation rates showed higher initial response density compared to the others (p < 0.001). Eyes with moderate DR had better response density compared to those with severe and proliferative DR (p = 0.001). At the beginning of the study, those eyes with proliferative and severe DR showed longer implicit times with respect to those with moderate DR (p = 0.04). The response density significantly increased in eyes that anatomically restored the IS/OS and the ELM after being treated with RNBZ (both p < 0.001). Similarly, eyes with spongiform DME further improved the response density with respect to those with cystic and serous DME (p < 0.001). On the contrary, eyes with hard exudates showed less improvement in their response density at the end of the study (p < 0.001). We observed a significant relationship between BCVA and the response density achieved at the end of the study (p = 0.012). Eyes with severe and proliferative DR significantly shortened implicit time compared to those with moderate DR (p = 0.04).

CONCLUSIONS

The multifocal electroretinogram allowed us to differentiate groups of eyes with DME according to their electrophysiological profile, both initially and after being treated with RNBZ. Ranibizumab increased the response density in all DME types included in the study, with a maximum response in those eyes with spongiform type. Once treated with RNBZ, the macular electrophysiological activity improved in eyes that had a well-preserved ellipsoid zone and ELM. The presence of hard exudates was a limitation to the response density achieved at the foveola.

7-Hexagon Multifocal Electroretinography for an Objective Functional Assessment of the Macula in 14 Seconds

PURPOSE

We present the multifocal electroretinogram (mfERG) with a 7-hexagon array as an objective test of macular function that can be recorded in 14 s. We provide normal values and investigate its reproducibility and validity.

METHODS

Healthy participants underwent mfERG testing according to International Society for Clinical Electrophysiology of Vision (ISCEV) standards using the Espion Profile/D310 multifocal ERG system (Diagnosys, LLC, Lowell, MA, USA). One standard recording of a 61-hexagon array and 2 repeated recordings of a custom 7-hexagon array were obtained.

RESULTS

A total of 13 subjects (mean age 46.9 years) were included. The median response densities were 12.5 nV/deg2 in the center and 5.2 nV/deg2 in the periphery. Intereye correlations were strong in both the center (ρCenter = 0.821; p < 0.0001) and the periphery (ρPeriphery = 0.862; p < 0.0001). Intraeye correlations were even stronger: ρCenter = 0.904 with p < 0.0001 and ρPeriphery = 0.955 with p < 0.0001. Bland-Altman plots demonstrated an acceptable retest mean difference in both the center and periphery, and narrow limits of agreement. We found strong correlations of the center (ρCenter = 0.826; p < 0.0001) and periphery (ρPeriphery = 0.848; p < 0.0001), with recordings obtained by the 61-hexagon method.

CONCLUSIONS

The 7-hexagon mfERG provides reproducible results in agreement with results obtained according to the ISCEV standard.

Wavelet decomposition analysis in the two-flash multifocal ERG in early glaucoma: a comparison to ganglion cell analysis and visual field

PURPOSE

To further improve analysis of the two-flash multifocal electroretinogram (2F-mfERG) in glaucoma in regard to structure-function analysis, using discrete wavelet transform (DWT) analysis.

METHODS

Sixty subjects [35 controls and 25 primary open-angle glaucoma (POAG)] underwent 2F-mfERG. Responses were analyzed with the DWT. The DWT level that could best separate POAG from controls was compared to the root-mean-square (RMS) calculations previously used in the analysis of the 2F-mfERG. In a subgroup analysis, structure-function correlation was assessed between DWT, optical coherence tomography and automated perimetry (mf103 customized pattern) for the central 15°.

RESULTS

Frequency level 4 of the wavelet variance analysis (144 Hz, WVA-144) was most sensitive (p < 0.003). It correlated positively with RMS but had a better AUC. Positive relations were found between visual field, WVA-144 and GCIPL thickness. The highest predictive factor for glaucoma diagnostic was seen in the GCIPL, but this improved further by adding the mean sensitivity and WVA-144.

CONCLUSIONS

mfERG using WVA analysis improves glaucoma diagnosis, especially when combined with GCIPL and MS.

The clinical characteristics and prognosis of acute zonal occult outer retinopathy

PURPOSE

This prospective observational case series study aimed to observe the clinical characteristics of acute zonal occult outer retinopathy (AZOOR) and its prognosis in Chinese Han patients.

METHODS

Six eyes of 5 female patients diagnosed with AZOOR were followed up for 4 months to observe the natural disease course. All enrolled subjects underwent a series of ocular examinations at the onset and each return visit, including best corrected visual acuity (BCVA), split lamp microscopy, fundus photography, optical coherence tomography (OCT), perimetry, multifocal electroretinogram and fundus fluorescein angiography.

RESULTS

Over the follow-up, all enrolled patients recovered on BCVA, perimetry and OCT in different degrees. Among them, one patient recovered completely since the ocular examination results returned to normal.

CONCLUSION

AZOOR is a rare ocular disorder in Chinese population. Our results demonstrated that visual functions of enrolled patients significantly improved spontaneously, indicating that Chinese female Han patients with AZOOR have good visual outcomes during the follow-up period without any specific managements.

Correlation of macular structure and function in a boy with primary foveomacular retinitis and sequence of changes over 5 years

PURPOSE

To describe the clinical characteristics, macular structure and function, and to document sequential changes over 5 years in a 10-year-old boy with bilateral primary foveomacular retinitis.

METHODS

A 10-year-old boy presented with sudden onset scotoma in both eyes, experienced after getting up from bed on a non-eclipse day. He persistently denied direct sun-gazing. He neither had any significant systemic illness, nor was using any medications. In addition to a detailed examination at presentation that included fundus fluorescein angiogram (FFA), electroretinogram (ERG), pattern ERG and electrooculogram (EOG), he was examined periodically for 5 years with Humphrey visual field (HVF), spectral domain optical coherence tomogram (SDOCT), Amsler grid charting and multifocal ERG. The macular structure and functions were analyzed over the years and correlated with the symptoms.

RESULTS

All findings were bilaterally symmetrical at each visit. At presentation, his corrected visual acuity was 20/25 with subfoveal yellow dot similar to solar retinopathy, central scotoma with reduced foveal threshold in HVF 24-2, micropsia in Amsler grid, missing of two plates on Ishihara color vision chart, transfoveal full thickness hyper-reflective band on SD OCT, unremarkable FFA and normal foveal peak in mfERG. The flash ERG and EOG were unremarkable. A month later, his VA improved to 20/20, he had relative scotoma in Amsler grid, no scotoma in HVF (10-2), restoration of the inner segment of the photoreceptors with sharp defect involving ellipsoid and photoreceptor interdigitation zone in SDOCT and blunting of foveal peaks in mfERG. Three months later, his corrected VA was 20/20 with relative scotoma in Amsler grid, normal color vision, no scotoma in HVF 10-2 and unchanged SDOCT findings. In subsequent examinations at 6, 9, 14, 29, 39 and 60 months, he was symptomless with VA 20/20, unremarkable fundus, normal Amsler grid and HVF (normal foveal threshold), unchanged SDOCT findings and the reduced foveal peaks on mfERG in both eyes got normalized only at 60 months.

CONCLUSION

Presented here is a case of bilaterally symmetrical idiopathic foveomacular retinitis that had a clinical appearance similar to solar retinopathy. The fundus changes persisted for 4 weeks, the symptoms and changes in Amsler grid lasted for 3 months, and the foveal threshold in visual fields normalized within 3 months. Maximum change in the SDOCT defect occurred within a month, and the extrafoveal defect in the ellipsoid and photoreceptor interdigitation line persisted despite resolution of symptoms and resolution of the visual field defect and normal distance vision. Probably, the foveal lesion detected on SDOCT was too small to cause a reduction in the distance visual acuity or show up in the visual field and mfERG later.

Test-retest reliability of the multifocal photopic negative response

PURPOSE

To assess the test-retest reliability of the multifocal photopic negative response (mfPhNR) of normal human subjects.

METHODS

Multifocal electroretinograms were recorded from one eye of 61 healthy adult subjects on two separate days using a Visual Evoked Response Imaging System software version 4.3 (EDI, San Mateo, California). The visual stimulus delivered on a 75-Hz monitor consisted of seven equal-sized hexagons each subtending 12° of visual angle. The m-step exponent was 9, and the m-sequence was slowed to include at least 30 blank frames after each flash. Only the first slice of the first-order kernel was analyzed. The mfPhNR amplitude was measured at a fixed time in the trough from baseline (BT) as well as at the same fixed time in the trough from the preceding b-wave peak (PT). Additionally, we also analyzed BT normalized either to PT (BT/PT) or to the b-wave amplitude (BT/b-wave). The relative reliability of test-retest differences for each test location was estimated by the Wilcoxon matched-pair signed-rank test and intraclass correlation coefficients (ICC). Absolute test-retest reliability was estimated by Bland-Altman analysis.

RESULTS

The test-retest amplitude differences for neither of the two measurement techniques were statistically significant as determined by Wilcoxon matched-pair signed-rank test. PT measurements showed greater ICC values than BT amplitude measurements for all test locations. For each measurement technique, the ICC value of the macular response was greater than that of the surrounding locations. The mean test-retest difference was close to zero for both techniques at each of the test locations, and while the coefficient of reliability (COR-1.96 times the standard deviation of the test-retest difference) was comparable for the two techniques at each test location when expressed in nanovolts, the %COR (COR normalized to the mean test and retest amplitudes) was superior for PT than BT measurements. The ICC and COR were comparable for the BT/PT and BT/b-wave ratios and were better than the ICC and COR for BT but worse than PT.

CONCLUSION

mfPhNR amplitude measured at a fixed time in the trough from the preceding b-wave peak (PT) shows greater test-retest reliability when compared to amplitude measurement from baseline (BT) or BT amplitude normalized to either the PT or b-wave amplitudes.

Variability of the multifocal electroretinogram based on the type and position of the electrode

PURPOSE

To evaluate and compare the wave amplitude of multifocal electroretinogram (mfERG) measurements and discomfort from Dawson-Trick-Litzkow (DTL) electrode located on the cornea (cDTL) and on the conjunctival fornix (fDTL) and ERG-jet contact lens electrode (CL).

METHODS

Thirty-six patients and 18 healthy volunteers were evaluated with three different methods (cDTL, fDTL and CL). Wave amplitude, number of artifacts, number of electrode dislocations and level of discomfort obtained with each electrode were compared. These variables were also compared between patients and healthy volunteers (control group). Comparisons between wave amplitudes were made using intraclass correlation coefficient (ICC).

RESULTS

Responses by the three tested electrode were better correlated (ICC) in patient (0.616-0.756) than in control groups (0.342-0.679). CL provided the highest wave amplitude in both groups (p < 0.005), but it was associated with higher discomfort (p < 0.001) and the highest rate of dislocations (72 and 100 % in control and patients, respectively). Looking at the differences obtained by each electrode between both groups, CL seems to be able to differentiate patient from control in the ring 1 of the mfERG. By contrast, fDTL gave the lowest wave amplitude in both groups, but it had the advantage to, apparently, discriminate between patients and control group in rings 1 and 2. cDTL produced more artifacts than the other electrodes in both groups (p < 0.001).

CONCLUSIONS

Although wave amplitude measurements with different electrodes were correlated, they cannot be directly compared, so it is mandatory to create an appropriate normative database with each electrode. Despite providing the lowest amplitudes, fDTL seems to offer the best features to perform mfERG regarding discomfort, number of artifacts and diagnostic capability.

A late foveal response component of multifocal electroretinograms in healthy subjects

PURPOSE

To investigate the characteristics of the late foveal response component (lfrc) that presents on the first slice of the second-order kernel (K2.1) in multifocal electroretinograms (mfERGs).

METHODS

mfERGs with 37 hexagonal stimulus elements were obtained from 27 healthy subjects under a stimulus intensity of 2.67 cds/m², base rate of 75 Hz, and a net recording time of 1 min 49.2 s, using bipolar contact lens electrodes. The responses on the centermost hexagon (with a diameter of 4.5°-5.2°) were designated as foveal mfERGs.

RESULTS

The foveal mfERG of the first-order kernel (K1) was shaped similarly to the K1 of the surrounding mfERGs. The foveal mfERG of K2.1 differed from the K2.1s of the surrounding mfERGs. This difference varied among subjects; however, the potential (0.34 ± 0.10 µV: mean ± SD) of the lfrc acutely changed at approximately 50 ms (range 48.56 ± 1.02-56.86 ± 1.99 ms). Whereas the amplitudes of the other major components of K1 and K2.1 significantly decreased with increasing refractive error, the amplitude of lfrc was not significantly correlated with refraction in this cohort.

CONCLUSIONS

The lfrc was obtained only on the centermost hexagon within an appropriate recording time (<2 min). This finding reflects the particular structure and peculiar adaptiveness of the fovea, a specialized area of the human retina, and enables the estimation of foveal function in clinical practice.

Functional improvement assessed by multifocal electroretinogram after Ocriplasmin treatment for vitreomacular traction

Background

To evaluate the functional recovery of patients with symptomatic vitreomacular traction (VMT) after Ocriplasmin treatment.

Methods

Prospective, single centre, consecutive case series. Patients were treated with a single intravitreal injection of Ocriplasmin (Jetrea, Thrombogenics Inc, USA, Alcon/Novartis EU). The following outcome measures are considered: resolution of VMT, evaluated through the use of optical coherence tomography (SD-OCT), functional recovery evidenced by multifocal-electroretinogram (mfERG) and microperimetry (MP1) after treatment with Ocriplasmin.

Results

Four eyes of four patients were treated with Ocriplasmin injection. We observed a VMT non-surgical resolution in all patients. The longitudinal statistical analysis showed a significant improvement of best corrected visual acuity (BCVA) in the treated eye of about 0.97 letters/week (p = 0.033). No significant difference was observed in mean sensitivity (p > 0.05) assessed by MP1 in both eyes, while improvement in fixation stability was assessed in treated eyes (β = 0.39; p = 0.029). In the four treated eyes mfERG revealed an increased foveal peak response over the follow-up. The longitudinal analysis of mfERG data shows a significant increase of N1 and P1 amplitude in the first rings and a significant decrease of N1 and P1 implicit time in most rings.

Conclusions

We report on four cases with resolution of VMT after Ocriplasmin treatment. Our preliminary results demonstrate that Ocriplasmin is safe and effective in the treatment of VMT, because it not only leads to a morphological recovery but mostly to a restoration of macular functionality, evaluated through the use of different objective tests, such as MP1 and mfERG over a six-month follow-up.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0284-3) contains supplementary material, which is available to authorized users.

The diagnosis and assessment of visual function in Singaporean children with electrophysiology: 10-year results

PURPOSE

To study the clinical use and efficacy of electrophysiology in children.

METHODS

This was a retrospective review of all children aged <16 years, who were referred to the Visual Electrophysiology Laboratory at the Singapore National Eye Center between 2003 and 2013.

RESULTS

A total of 586 children, median age 8 years (range 0.15-16), were referred for a variety of reasons including investigation of poor vision (40 %), suspected retinal disease or optic nerve/cortical dysfunction (17 %), nystagmus (13 %) and screening or monitoring of a variety of ocular or neurological conditions (12 %). The number of children with vision 6/15 or worse was 418 (71 %), and 103 (18 %) had vision 6/120 or worse in at least one eye. The most common pathology noted was retinal dystrophy or dysfunction (41 %) or optic nerve/cortical dysfunction (12 %). In 30 %, visual electrophysiology was within normal limits, and in 6 %, a conclusive diagnosis could not be obtained.

CONCLUSION

Electrophysiology testing played an important role in the assessment of children and added to the clinical management of the patient.

The effect of nutritional supplementation on the multifocal electroretinogram in healthy eyes

BACKGROUND

Previous studies have demonstrated an increase in macular pigment optical density (MPOD) with lutein (L)-based supplementation in healthy eyes. However, not all studies have assessed whether this increase in MPOD is associated with changes to other measures of retinal function such as the multifocal ERG (mfERG). Some studies also fail to report dietary levels of L and zeaxanthin (Z). Because of the associations between increased levels of L and Z, and reduced risk of AMD, this study was designed to assess the effects of L-based supplementation on mfERG amplitudes and latencies in healthy eyes.

METHODS

Multifocal ERG amplitudes, visual acuity, contrast sensitivity, MPOD and dietary levels of L and Z were assessed in this longitudinal, randomized clinical trial. Fifty-two healthy eyes from 52 participants were randomly allocated to receive a L-based supplement (treated group), or no supplement (non-treated group).

RESULTS

There were 25 subjects aged 18-77 (mean age ± SD; 48 ± 17) in the treated group and 27 subjects aged 21-69 (mean age ± SD; 43 ± 16) in the non-treated group. All participants attended for three visits: visit one at baseline, visit two at 20 weeks and visit three at 40 weeks. A statistically significant increase in MPOD (F = 17.0, p ≤ 0.001) and shortening of mfERG ring 2 P1 latency (F = 3.69, p = 0.04) was seen in the treated group.

CONCLUSIONS

Although the results were not clinically significant, the reported trend for improvement in MPOD and mfERG outcomes warrants further investigation.

The effects of fundus photography on the multifocal electroretinogram

PURPOSE

To determine the effect of flash fundus photography (FFP) on the multifocal electroretinogram (mfERG).

METHODS

Ten subjects underwent mfERG testing on three separate dates. Subjects received either mfERG without FFP, mfERG at 5 and 15 min after FFP, or mfERG at 30 and 45 min after FFP on each date. The FFP groups received 10 fundus photographs followed by mfERG testing, first of the right eye then of the left eye 10 min later. Data were averaged and analyzed in six concentric rings at each time point. Average amplitude and implicit times of the N1, P1, and N2 peaks for each concentric ring at each time point after FFP were compared to baseline.

RESULTS

Flash fundus photography did not lead to a significant change of amplitude or implicit times of N1, P1, or N2 at 5 min after light exposure.

CONCLUSIONS

These findings suggest that it is acceptable to perform mfERG testing without delay after performance of FFP.

Linezolid induced retinopathy

PURPOSE

While optic neuropathy is a well-known cause of visual disturbances in linezolid-treated patients, the possibility of linezolid-related retinopathy has not been investigated. Here, we report a case of retinopathy demonstrated by multifocal electroretinogram (mfERG) in a linezolid-treated patient.

METHOD AND RESULTS

A 61-year-old man with extensively drug-resistant pulmonary tuberculosis treated with linezolid for 5 months presented with painless loss of vision in both eyes. The patient's best corrected visual acuity was 20/50 in the right eye and 20/100 in the left eye. Fundus examination revealed mild disc edema, and color vision was defective in both eyes. Humphrey visual field tests showed a superotemporal field defect in the right eye and central and pericentral field defect in the left eye. Optical coherence tomography (OCT) revealed only mild optic disc swelling. In mfERG, central amplitudes were depressed in both eyes. Four months after the cessation of linezolid, visual acuity was restored to 20/20 right eye and 20/25 left eye. The color vision and visual field had improved. The OCT and mfEFG findings improved as well.

CONCLUSIONS

Although the clinical features were similar to linezolid-induced optic neuropathy, the mfERG findings suggest the possibility of a retinopathy through cone dysfunction.

Macular function measured by binocular mfERG and compared with macular structure in healthy children

PURPOSE

To create normative data in children from binocular multifocal ERG (mfERG) recordings and compare results with the macular thickness.

METHODS

Forty-nine 5- to 15-year-old healthy, full-term children were examined with Espion Multifocal System, using DTL electrodes. The stimulus matrix consisted of 37 hexagonal elements. Amplitudes, implicit times and response densities (presented in three rings) of the first-order component P1 were analyzed. Measurements of macular thickness were performed with spectral-domain Cirrus OCT.

RESULTS

There were no significant differences between right and left eyes regarding mfERG recordings. Median P1 implicit times of Rings 1-3 of the 46 right eyes were 30.0, 30.0 and 30.8 ms and response densities 20.5, 10.9 and 7.6 nV/deg(2), respectively. Implicit time was longer in boys than in girls (p = 0.009, 0.039, 0.005 in Rings 1-3) and was correlated with age (r s = 0.417, 0.316, 0.274 in Rings 1-3). Implicit time in Ring 1 correlated significantly with the inner circle of the OCT measurements (p = 0.014).

CONCLUSION

Binocular mfERG with DTL electrodes is a reliable test of the central macular function in children and correlates with macular structure. As previously not shown, there was a significant difference in implicit time between boys and girls.

Changes in optical coherence tomography findings in acute zonal occult outer retinopathy

Purpose

To report a case of acute zonal occult outer retinopathy (AZOOR) in a 39-year-old woman.

Methods

Images were obtained with fundus photography and optical coherence tomography (OCT). A multifocal electroretinogram (mfERG) was also obtained to evaluate retinal function.

Results

The patient's right visual acuity was 0.8. Fundus photographs showed no specific abnormal findings. OCT showed attenuation of the photoreceptor inner segment/outer segment (IS/OS) line and the cone outer segment tip (COST) line in the right eye. The mfERG showed corresponding amplitude reductions. One month after the initial visit, her right visual acuity improved to 1.2. There was partial recovery of the IS/OS line; however, the COST line was still absent, and there was no apparent improvement in the mfERG responses.

Conclusions

Our findings showed a discrepancy between the microstructural findings and visual function during recovery of AZOOR.

An optical coherence tomography and fundus autofluorescence imaging study of peripapillary acute zonal occult outer retinopathy

PURPOSE

To evaluate peripapillary acute zonal occult outer retinopathy in a 67-year-old man.

METHODS

Images were obtained using fundus photography, fluorescein angiography (FA) and indocyanine green angiography (ICGA), fundus autofluorescence (FAF) imaging, and optical coherence tomography (OCT). Visual field testing and multifocal electroretinogram (mfERG) were also performed to evaluate retinal function.

RESULTS

Fundus photographs showed subtle pigmentary changes in the peripapillary region, while FAF imaging showed clearly defined hypofluorescent areas in the peripapillary region. Intense hyperfluorescent lesions were also seen underneath hypofluorescent areas. A transmission defect with a granular hyperfluorescence was visible on FA, and ICGA showed hypofluorescence within the lesion. The outer border of the peripapillary zone appeared to block the underlying choroidal fluorescence. The photoreceptor inner segment/outer segment line was absent on OCT images from this area in both eyes, and hyperreflective punctate drusen-like materials were present at the outer border of the peripapillary zone. Visual field testing by Goldmann perimetry showed blind-spot enlargement, and mfERG showed corresponding amplitude reductions.

CONCLUSIONS

We speculate that the intense hyperautofluorescent material at the outer border of the peripapillary zone might be accumulated drusenoid lipofuscin.

Acute Visual Field Defect following Vitrectomy Determined to Originate from Optic Nerve by Electrophysiological Tests

Purpose

To present our findings on the cause of an acute visual field defect (VFD) that developed in a patient on the day after vitrectomy for proliferative diabetic retinopathy.

Case

A 50-year-old man complained of a blind area in the superior visual field that developed one day after vitrectomy. The patient had undergone uncomplicated vitrectomy for a long-duration vitreous hemorrhage associated with proliferative diabetic retinopathy. Residual vitreous hemorrhage hampered a clear view of the fundus. Goldmann perimetry showed a horizontal VFD in the superior field. The area corresponding to the VFD was examined by multifocal electroretinograms (mfERGs) and multifocal visual evoked potentials (mfVEPs). The amplitudes of the mfVEPs were reduced with prolonged implicit times especially when the superior hemifield was stimulated, while the amplitudes and implicit times were within the normal range when other parts of the visual field were stimulated. In addition, the full-field photopic ERGs and photopic negative responses were attenuated in the right eye. These findings suggested that the VFD did not originate from alterations in the retinal inner and middle layer but in the ganglion cells. The visual acuity improved to 1.2 but his optic disc became pale and the VFD remained unchanged more than 12 years after the surgery.

Conclusion

We suggest that vitrectomy can cause ischemic optic neuropathy by interfering with the circulation associated with diabetes mellitus. Evaluations by mfERGs, mfVEPs, and full-field photopic ERGs were helpful in making the diagnosis.

Focal functional and microstructural changes of photoreceptors in eyes with acute zonal occult outer retinopathy

PURPOSE

Acute zonal occult outer retinopathy (AZOOR) is characterized by an acute zonal loss of outer retinal function with minimal ophthalmoscopic changes in one or both eyes. We present a patient with AZOOR whose ultrastructural and functional findings were followed for 8 months.

CASE

A 22-year-old woman developed an acute central scotoma in her right eye. Her best-corrected visual acuity (BCVA) was 0.5 OD and 1.2 OS. The ophthalmoscopic examinations, fluorescein angiography, and full-field electroretinograms (ERGs) were normal in both eyes. The amplitudes of the multifocal ERGs (mfERGs) were attenuated in the area corresponding to the scotoma. Spectral domain optical coherence tomography showed an absence of both the inner and outer segment (IS/OS) line of the photoreceptors and the cone outer segment tip (COST) line between the IS/OS line and the retinal pigment epithelium. These changes were seen in the area corresponding to the scotoma. One month later, the scotoma disappeared and the BCVA improved to 1.2 OD. The mfERGs increased to almost the same amplitude as the fellow eye. The IS/OS line became discernible but the COST line was still absent. The ophthalmological findings of the right macula remained normal during the 11-month follow-up period.

CONCLUSIONS

Our findings indicate that the selective loss of the IS/OS and the COST lines is probably the morphological alterations corresponding with the reduced BCVA and the mfERGs in the areas of the visual field defects in the acute phase of AZOOR. But in the recovery phase, only the abnormality of the COST line is a subclinical sign for the disease. These findings should be important in understanding and evaluating the pathological mechanism in other outer retinal diseases.