Detection using the multifocal electroretinogram of mosaic retinal dysfunction in carriers of X-linked retinitis pigmentosa

PURPOSE: To examine whether a mosaic pattern of retinal dysfunction in obligate carriers of X-linked retinitis pigmentosa (XLRP) could be observed in local electroretinographic responses obtained with the multifocal electroretinogram (mfERG). DESIGN: Prospective observational case series. PARTICIPANTS: Five obligate carriers of XLRP (mean age, 53.2 years) were recruited into the study. METHODS: Examination of each subject included a complete ocular examination, Humphrey visual field, standard full-field electroretinogram (ERG), and mfERG testing. For the mfERG, we used a 103-scaled hexagonal stimulus array that subtended a retinal area of approximately 40 in diameter. The amplitudes and implicit times in each location for the mfERG was compared with the corresponding value determined for a group of normally sighted, age-corrected control subjects. MAIN OUTCOME MEASURES: Mapping of 103 local electroretinographic response amplitudes and implicit times within the central 40 with the multifocal electroretinogram. RESULTS: Localized regions of reduced mfERG amplitudes and/or delayed implicit times were found in four of five carriers. In one of these four carriers, a mosaic pattern of mfERG dysfunction was present even in the absence of any clinically apparent retinal changes, retinal sensitivity losses on Humphrey field testing, or abnormal full-field cone ERG responses. However, one carrier with a typical tapetal-like reflex demonstrated no deficit on any functional tests. CONCLUSIONS: The mfERG demonstrated patchy areas of retinal dysfunction in some carriers of XLRP. This mosaic pattern of dysfunction may be observed in some patients with a normal-appearing fundus, normal psychophysical thresholds, and normal amplitude and implicit time full-field ERG cone responses.     

Mapping of retinal function in Best macular dystrophy using multifocal electroretinography

In order to evaluate the function of the retina in Best macular dystrophy (BMD) 18 patients were examined by means of the multifocal electroretinogram (mfERG). The mfERG peak amplitudes of the central and pericentral responses were significantly reduced in the BMD patients (p<0.001). The ERG amplitude decrease of the central response was significantly correlated with visual acuity loss and with the funduscopic staging. The implicit times in more eccentric groups were slightly but significantly increased. The markedly reduced mfERG amplitudes with only slightly increased implicit times may indicate cone photoreceptor cell loss or damage to the cone outer segments.     

Fundus autofluorescence and mfERG for early detection of retinal alterations in patients using chloroquine/hydroxychloroquine

PURPOSE: To evaluate and compare the value of fundus autofluorescence (FAF) imaging and multifocal electroretinography (mfERG) in early detection of retinal alterations in patients using chloroquine/hydroxychloroquine (CQ/HCQ). METHODS: FAF imaging was performed in a consecutive series of 25 patients with long-term CQ or HCQ treatment (duration, >1 year), with or without visual disturbances. In addition, mfERG was performed in accordance with ISCEV (International Society for Clinical Electrophysiology of Vision) guidelines in 23/25 patients. RESULTS: In 10/25 patients alterations of FAF were observed. Mild changes were limited to a pericentral ring of increased FAF. More advanced stages presented as pericentral mottled loss of FAF with increased FAF in the adjacent retina and later on a complete loss of pericentral FAF. In one case, a pericentral ring was observed when ophthalmoscopy and fluorescein angiography were normal. Marked progression of FAF abnormalities was observed during a 3-year follow-up in two of three patients. With the mfERG, pericentral, central, or generalized amplitude reductions were detected in all patients with FAF abnormalities and in an additional four patients with normal FAF. CONCLUSIONS: FAF imaging can be reliably used to detect early retinal pigment epithelial alterations in CQ/HCQ retinopathy. Ophthalmoscopy and fluorescein angiography appear to be less sensitive. With the mfERG, more retinal abnormalities were detected compared with FAF imaging.     

Electrophysiologic and phenotypic features of an autosomal cone-rod dystrophy caused by a novel CRX mutation

PURPOSE: To reexamine a large Albertan family previously reported with a progressive cone dystrophy with variable phenotype and to map the disorder using molecular genetic techniques. DESIGN: Observational case series. PARTICIPANTS: Twenty-nine subjects (10 affected) from four generations of a large kindred were clinically examined. Twenty-three of these individuals, as well as two unaffected spouses, were included in the molecular genetic study. Subject ages ranged from 17 to 91 years of age. METHODS: Disease status and associated ocular abnormalities were assessed primarily by measurement of visual acuity, color vision, fundus photography, and both full-field and multifocal electroretinography (ERG and mfERG). Linkage of the disorder to the rhodopsin gene was studied using microsatellites. A mutational screen of the CRX gene was performed to identify coding sequence changes. MAIN OUTCOME MEASURES: Visual acuity and color discrimination were reduced in clinically affected individuals; full-field flash ERG was used to measure function of both cones and rods. mfERG and fundus photography allowed documentation of the observed macular changes. RESULTS: We noted a variable, adult-onset macular dystrophy, progressing in some cases to a retinitis pigmentosa-like phenotype. Both photopic and scotopic full-field ERG amplitudes were reduced by approximately 50%, demonstrating involvement of both photoreceptor systems. A reduced b-wave amplitude with a relatively preserved a-wave was observed at both cone and rod levels. Macular involvement was confirmed by mfERG. The rhodopsin locus was excluded by haplotype analysis. A novel frameshift mutation was detected in exon III of the CRX retinal homeobox gene. ERG and molecular genetic findings were consistent with the reclassification of this disease as an autosomal dominant cone-rod dystrophy (CRD) CONCLUSIONS: We report a novel CRX mutation causing autosomal dominant CRD. Observed ERG changes suggest that this mutation primarily impairs inner retinal function. Because retinal expression of CRX is limited to photoreceptors, this dysfunction may be the result of faulty photoreceptor communication with second-order retinal neurons. We propose misexpression of gated cation channels caused by altered CRX activity as one putative mechanism by which a sole photoreceptor defect may selectively impair neurotransmission without disrupting the upstream events of phototransduction.     

Retinal degeneration in cats fed casein. I. Taurine deficiency.

All cats fed a taurine-free casein diet for at least 23 weeks have shown granularity with a hyper-reflective white zone in the area centralis, nondetectable electroretinograms (ERG's), and structural changes indicating photoreceptor cell degeneration. The present study has demonstrated that cats fed this casein diet have a selective decrease in plasma and retinal taurine concentrations by five weeks; taurine levels were about 4 per cent of normal in plasma, and 60 per cent of normal in retina. After 10 weeks, taurine levels were 2 to 4 per cent of normal in plasma and reached a minimum of 20 to 30 per cent of normal in the retina. These biochemical changes occurred in association with a delay in the cone ERG implicit time at five weeks and reduced cone and rod ERG amplitudes at 10 weeks. During this period, retinal DNA content (as a measure of cell viability) and fundus appearance were normal. By 23 weeks, ERG's were nondetectable, retinal DNA content was reduced, and the fundus showed typical changes in the area centralis. These studies help to establish a biological role for taurine in maintaining photoreceptor cell function and viability in the cat.     

Cone and rod ERGs in degenerations of central retina

Sixty-four patients with retinal degenerations at the posterior pole were reviewed and their ERGs analysed. On the basis of symptoms, visual acuity, ophthalmoscopy and cone/rod ERG the patients were divided into five diagnostic groups: Stargardt's disease, fundus flavimaculatus, cone degeneration, dominant drusen and central retinitis pigmentosa (RP). Stargardt's disease and fundus flavimaculatus show low-normal or subnormal cone b-wave amplitudes, often with prolonged peak times; the rod ERG is rarely abnormal. Cone degeneration presents with reduced visual acuity, photophobia, nystagmus and minimal fundus changes. The ERG shows severely reduced cone b-waves and increased peak times; the rod b-waves are in the low-normal or subnormal range. Dominantly inherited drusen, included for comparison, revealed little change in the ERG in spite of widespread ophthalmoscopic changes: b-wave amplitudes fall mostly in the low-normal range, and their peak times may be prolonged. RP of the central type reveals considerable variability in all clinical aspects, but the cone and rod ERGs are consistently greatly reduced, showing markedly increased peak times of the cone b-waves. Recording of the Ganzfeld ERG with cone/rod separation thus proves useful in differentiating degenerations of the central retina.     

Electrophysiological studies in newly onset type 2 diabetes without visible vascular retinopathy

The purpose of this study was to investigate the early alterations of retinal function, assessed with electrophysiology, in newly onset type 2 diabetes patients without vascular retinopathy. Seventeen patients with newly diagnosed type 2 diabetes (duration 7±3 months), without any vascular retinopathy in fundus photographs, were examined with full-field electroretinogram (ERG) and multifocal ERG (mfERG). The results were compared with those of age-matched subjects without diabetes. In the dark-adapted full-field ERG, the a-wave and the 30-Hz flicker implicit times were delayed in diabetes patients compared to controls, P=0.001 and P=0.020. In the first-order kernel of the mfERG, the first positive wave, P1, was delayed in all areas measured. The electrophysiological examinations demonstrate early alterations of retinal function characterised by a delayed a-wave implicit time in the dark-adapted full-field ERG, representing the rod signalling, and alterations in the multifocal ERG reflecting cone and/or postreceptoral function.     

Electroretinographic abnormalities in multiple sclerosis: possible role for retinal autoantibodies

Background Multiple sclerosis (MS) has been associated with inflammation of the uveal tract, suggesting an immunological link between the uvea and central nervous system (CNS) in this disease. The retina is embryologically derived from the CNS, and it is conceivable that retinal antigens may also be recognized by the immune system in MS. Electroretinographic abnormalities, as well as retinal autoantibodies, have previously been described in MS. We performed this study to further explore the possibility of retinal autoimmunity in MS.Methods Thirty-four patients with clinically definite MS and thirty-seven healthy controls were recruited. All patients and controls had standard electroretinographic (ERG) testing done, as well as a brightflash ERG protocol to isolate rod photoreceptor function. Patient and control sera were analyzed for the presence of antiretinal antibodies using Western blot techniques.Results We found statistically significant differences between MS patients and controls in four ERG parameters. In the MS group, implicit times of the rod-cone b-wave response, cone b-wave response, and rod photoreceptor response were increased. The amplitudes of the photopic oscillatory potentials were reduced in the MS group. Patients with the highest titres of retinal autoantibodies had delayed rod-cone b-wave implicit times and diminished photopic oscillatory potential amplitudes.Conclusions We report ERG evidence of retinal dysfunction in patients with MS. We also report the first use of the brightflash ERG protocol in MS, which demonstrated rod photoreceptor dysfunction. Patients with the highest antiretinal antibody titres had abnormal ERG recordings. Retinal autoimmunity is a possible explanation for these observed ERG abnormalities in MS patients.     

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.

     

遗传性视网膜劈裂症的多焦视网膜电图改变

目的应用多焦视网膜电图对正常对照 眼和视网膜劈裂眼进行检测并比较两者之间的差异。 方法用VERIS Science^TM 4.0视诱发反应图像系统对19例(21只眼)正常对照者和8例 (15只眼)视网膜劈裂者进行检测,并用全视野视网膜电图 (electroretinogram,ER G) 对其中3例 (6只眼) 视网膜劈裂者进行检测。结果正常对照组和视网膜劈裂组6个环形视网膜区域平均反应密度值或潜伏期比较均显示差异有非常显著性的意义,视网膜劈裂患者多焦ERG三维图皆表现为多处局部性振幅降低,中央高峰反应消失或降低,其6个环形视网膜区域反应密度值的P₁/N₁波比值不同于全视野ERG的b/a波比值。 结论多焦ERG和全视野ERG对视网膜劈裂的诊断各有其优点。(中华眼底病杂志,2001,17:268-270)     

Fundus autofluorescence in patients with leber congenital amaurosis

PURPOSE: Fundus autofluorescence (FAF), as an index of lipofuscin accumulation in the retinal pigment epithelium (RPE), provides indirect information on the level of metabolic activity of the RPE and thus the integrity of the RPE/photoreceptor complex. To investigate whether the photoreceptor/RPE complex is still viable in patients with Leber congenital amaurosis (LCA), FAF imaging was performed. METHODS: Three patients with LCA (patients A, B, and C; ages, 24, 15, and 37 years, respectively) were enrolled and one patient with RP with preserved visual acuity (age, 28 years) was included as a control. The diagnosis was based on history, visual function, and Ganzfeld electroretinography (International Society for Clinical Electrophysiology of Vision [ISCEV] standard). FAF was recorded with a confocal scanning laser ophthalmoscope (cSLO; Heidelberg Retina Angiograph; Heidelberg Engineering, Heidelberg, Germany). RESULTS: All patients with LCA had vision reduced to perception of light and had undetectable ERGs. FAF was normal in patient A. In patient B, there was a parafoveal ring of mildly increased FAF. The midperiphery showed mildly decreased FAF. Patient C showed a parafoveal ring of moderately increased FAF. FAF was moderately decreased along the arcades and the midperiphery. The patient with RP showed a parafoveal ring of moderately increased FAF and severely decreased FAF eccentric to the macula including the periphery. CONCLUSIONS: The FAF findings in these patients with LCA suggest that there is continuous metabolic demand from the photoreceptors and that the RPE/photoreceptor complex is, at least in part, anatomically intact, but the photoreceptors have lost function. These findings may have implications for future treatment. It is notable that more than 20 years of severe visual impairment associated with LCA can be associated with normal FAF, indicating that photoreceptor function may be rescuable.     

Ganzfeld and multifocal electroretinography in Malattia Leventinese and Zermatt Macular Dystrophy

BACKGROUND: To show the value of Ganzfeld electroretinography (ERG) in Malattia Leventinese (ML, or Hereditary Dominant Drusen) and Zermatt Macular Dystrophy (ZMD) and to illustrate multifocal electroretinography (mfERG) in 2 cases of ML. PATIENTS AND METHODS: In 15 patients with ML and 14 with ZMD we recorded Ganzfeld ERGs along with clinical examinations. In two patients with ML, and an we also performed a mfERG and an automated and Goldmann perimetry. All patients had a genotypic confirmation of the respective disease. For ERG measurements, the UTAS-3000 system was used, the mfERG was recorded using the RetiScan system. RESULTS: In ML, the visual acuity remained at 0.8 or higher until the 5 (th) or 6 (th) decade of life, followed by a rapid drop. In ZMD, the decrease in acuity began already in the 3 (rd) decade and followed a more continuous time course. The time course of the decrease of the ERG b-wave amplitudes was nearly identical for either disease. The mfERG showed in one case of ML a marked reduction in the macular response density but, in the second case, a normal density response pattern despite large degenerative changes at the posterior pole. In both of these patients, we found no visual field defects. CONCLUSIONS: Patient history and clinical testing raised the suspicion of a hereditary macular dystrophy. By means of Ganzfeld and multifocal electroretinography the course of the disease could be observed. However, definite diagnosis could only be established by genetic identification.     

The multifocal electroretinogram in X-linked juvenile retinoschisis

To measure and compare the multifocal electroretinography in normal control and X-linked juvenile retinoschisis, 13 cases (13 right eyes) of normal control and nine cases (17 eyes) of X-linked juvenile retinoschisis were measured with VERIS Science 4.0. Four cases (eight eyes) out of the nine retinoschisis cases were tested with Ganzfeld ERG at the same day. The results showed statistically significant difference of average response densities and latencies in six ring retinal regions between the normal control and retinoschisis. The trace array and 3-D topography of multifocal ERG showed multi-area amplitude decrease with absence or reduction of central peak amplitude in patients with retinoschisis. The P₁/N₁ ratio of multifocal ERG average response densities in six ring retinal regions was different from the b/a ratio of Ganzfeld ERG. The multifocal ERG and Ganzfeld ERG each had its advantage in the diagnosis of retinoschisis.     

Diffuse retinal injury from a non-penetrating TASER dart

To describe a non-penetrating TASER gun injury resulting in a small exudative retinal detachment but significant visual acuity and retinal function loss as demonstrated by electroretinography (ERG). A 39-year-old man presented to the emergency department with a TASER barb embedded in his right lower lid. A complete clinical ophthalmologic examination and surgical extrication were performed, as well as radiologic imaging and Ganzfeld electroretinography. No scleral penetration was observed on surgical exploration. Retinal examination showed a peripheral exudative detachment. Subsequent follow-up revealed progressive resolution of the detachment and improvement in visual acuity. The ERG showed a 63–70% decrease in rod a- and b-waves, while isolated cone responses were reduced by only 10%, with a minimal increase in implicit time. This case shows that periocular TASER injuries, even if apparently superficial, may result in significant ocular damage. ERG may be useful in the diagnosis of visual loss attributed to disturbance in photoreceptor function, in the absence of anatomically evident damage.     

视网膜电图和多焦视网膜电图ON/OFF反应的研究进展

ON/OFF反应是人们从视网膜电生理反应中记录到的视网膜给光、撤光反应。它是通过不同的光感受器细胞形成不同的ON/OFF通路来完成。视网膜电图（ERG）和多焦视网膜电图（mf-ERG）ON/OFF反应的异常可明确提示ON/OFF通路及通路相关细胞的异常,在临床多种疾病,如先天性静止性夜盲,X连锁青年性视网膜病变等的诊断与治疗中有着重要意义。就ON/OFF通路（视锥ON/OFF通路,视杆ON/OFF通路,视杆慢快ON/OFF通路）和ERG、mfERGON/OFF反应的最佳记录方法、条件及在临床中的应用进行综述。     

Selective reduction of S-cone response and on-response in the cone electroretinograms of patients with X-linked retinoschisis

PURPOSE: To examine the electroretinograms (ERGs) of the short-wavelength-sensitive (S-) and the mixed long- and middle-wavelength-sensitive (L,M-) cones, and the ON- and OFF-responses of the cone ERGs in three patients with X-linked juvenile retinoschisis (XLRS). METHODS: Cone ERGs elicited by different color flashes and those elicited by long duration stimuli under Ganzfeld conditions were recorded from three patients with XLRS. RESULTS: The S-cone b-waves were undetectable to short-wavelength stimuli in all three XLRS patients, while the L,M-cone ERG b-waves were within the normal range. To long-duration white stimuli, the ON-response (b-wave) was reduced and delayed in all patients compared with that of the normal subjects, while the d-wave or OFF-response appeared normal in amplitude and implicit time. CONCLUSIONS: These results support the hypothesis that the normal S-cone ERG arises primarily from the ON-pathway of the cone ERGs and the hypothesis that ON-bipolar cells are predominant in the S-cone system.     

ERG evaluation of daily,high-dose sildenafil usage

Purpose Sildenafil can cause transient, mild ERG changes in healthy individuals taking large single doses. Although the drug was originally intended for intermittent use in erectile dysfunction, it has now been approved for chronic use in subjects with pulmonary arterial hypertension (PAH). The purpose of our study is to investigate possible ERG changes in subjects using large doses of sildenafil on a chronic daily basis. Methods We examined five subjects with PAH taking sildenafil daily for 1–4 years. Full-field electroretinogram (ERG), multifocal ERG (mfERG), and color testing were performed. Three of the subjects returned on a later date for challenge off and on the medication. Results On chronic daily sildenafil, color vision testing was normal, and ERG and mfERG amplitudes were normal; however, cone implicit times on drug were modestly lengthened. There were no consistent full-field ERG changes when off the drug, but the mfERG showed a small amplitude increase and implicit time decrease, which returned 1 h after re-dosing. Conclusion There was a modest lengthening of cone implicit time on chronic daily doses of sildenafil and a hint that some of these changes may be reversible in the short term. It does not appear that chronic sildenafil usage at these dosage levels is seriously toxic or threatening to vision. Presented in part at the Association of Research in Vision and Ophthalmology (ARVO) annual meeting, Fort Lauderdale, FL, May 2008.     

Regional variations in local contributions to the primate photopic flash ERG: revealed using the slow-sequence mfERG

PURPOSE: To determine the variations with eccentricity of the primate photopic ERG and to separate contributions by different retinal cells by using intravitreal pharmacologic agents. METHODS: Slow-sequence multifocal (mf)ERGs were obtained from 19 anesthetized adult rhesus monkeys and 5 normal human subjects. Recordings in monkeys were obtained before and after injections of tetrodotoxin citrate (TTX) to block sodium-dependent spiking; TTX+N-methyl-D-aspartic acid (NMDA)+picrotoxin (PTX) or gamma-aminobutyric acid (GABA) to block all inner retinal activity; L-2 amino-4-phosphonobutyric acid (APB) to block the On-pathway; and cis-2, 3 piperidine dicarboxylic acid (PDA) to block the Off-pathway and the otherwise unblocked inner retinal activity. The stimulus consisted of 103 equal-sized hexagons within 17 degrees of the fovea; every 200 ms (15 frames), each hexagon had a 50% chance of remaining at 20 cd/m(2) or increasing briefly to 4.7 cd-s/m(2). Oscillatory potentials (OPs; 90-300 Hz) were extracted. RESULTS: The slow-sequence mfERG summed over the stimulated area looked similar to a standard photopic, full-field ERG, with a- and b-waves and OPs. OPs in the foveal and temporal retina were larger than in the nasal retina. This nasotemporal asymmetry was removed by TTX, and the OPs were eliminated, either by blocking inner retina activity or by blocking the On-pathway. The summed mfERG waveform, including OPs, was shaped mainly by the more peripheral retinal regions. The foveal b-wave peak occurred about 5 to 6 ms later than in the periphery, with the depolarizing peak of the On-pathway/bipolar contribution occurring earlier than the depolarizing peak of the Off contribution at all eccentricities. The a-wave was composed of a small photoreceptor contribution and postreceptoral portion originating from hyperpolarizing neurons. CONCLUSIONS: The variations in the primate photopic ERG with eccentricity are due to spike-driven oscillatory activity that is more prominent in central and temporal retina than in nasal retina and to the slower timing of all responses in the central, compared with the peripheral, retina. The full-field, photopic ERG most closely resembles the mfERG responses to stimulation of peripheral regions.     

Autofluorescence Imaging in Rubella Retinopathy

Purpose: To demonstrate that fundus autofluorescence (FAF) imaging aides the diagnosis of rubella retinopathy (RR). Methods: Four patients with sensorineural hearing loss underwent ophthalmic exams, electro-retinogram testing (ERG), and FAF in both eyes. Fluorescein angiogram (FA) was performed in one case. Results: Salt-and-pepper retinopathy was observed in seven eyes. FAF highlighted the fundus abnormalities with stippled fluorescence in all seven eyes. ERG showed normal retinal function in all eyes. Choroidal neovascularization was identified by FA in one eye. Conclusions: FAF is sensitive to the retinal pigment epithelium disturbance caused by rubella and noninvasively helps establish the diagnosis of RR.     

Assessing Responses of the Macula in Patients with Macular Holes using a New System Measuring Localized Visual Acuity and the mfERG

Purpose: To evaluate acuity and multifocal electroretinogram (mfERG) responses from the macula in affected and unaffected fellow eyes of patients with macular holes. Methods: We tested 10 eyes with macular hole and 10 fellow eyes from 11 patients. We measured local visual acuity thresholds at 27 discrete locations within 21° diameter using the Functional Fundus Imaging System (FFIS), a psychophysical system that measures visual acuity as a function of visual field location, and local ERG responses within 45° diameter using the mfERG. Results: In the affected eyes, the mean FFIS visual acuity thresholds were significantly elevated within the central 21° diameter area, compared to a group of control eyes. No significant differences were found between the acuities of the fellow eyes compared to those of the control group. The amplitudes of the first positive peak of the mfERG were reduced in the central 7.8° in affected eyes. In the central 2°, 4 out of 10 affected eyes showed non-measurable ERG signals. The remaining six eyes showed significantly reduced mean amplitudes, but not delayed implicit times, when compared to the control group. For the fellow eyes, the mean amplitudes of the mfERG and implicit times did not differ from the means of the control eyes. Conclusions: Both local psychophysical and electrophysiological testing demonstrated retinal dysfunction extending beyond the site of the macular holes in some patients (three of the patients had central mfERG amplitudes falling within the normal range).