mfERG Responses Research Articles

Evaluation of early changes of macular function and morphology by multifocal electroretinograms in patients with nasopharyngeal carcinoma after radiotherapy.

To assess the role of multifocal electroretinograms (mfERGs) and optical coherence tomography (OCT) for detecting early changes in macular functions of patients with nasopharyngeal carcinoma (NPC) after radiotherapy. mfERGs and OCT were used to examine a NPC group (36 NPC patients after radiotherapy without clinically visible radiation retinopathy, 36 eyes) and a normal control group (25 healthy individuals, 25 eyes) with the same procedure and parameters. The two groups of mfERG were summarized by calculating ring averages, response density, N1 amplitude and P1 and N1 latencies were analysed. OCT scan thickness was summarized into ETDRS regions for comparison. Compared with controls, the NPC group had significantly decreased P1 response densities in 1-4 ring regions and N1 amplitudes in 1-3 rings (P < 0.01). P1 latencies were obviously prolonged in rings 1 (P < 0.01). In four quadrants (inferonasal, superonasal, inferotemporal and superotemporal) of the mfERG response waveforms, the NPC group had significantly decreased P1 response densities and N1 amplitudes mainly in the inferonasal and inferotemporal quadrants, showing statistically significant differences from the control group (P < 0.0125). But for the OCT results, there is no statistically significant difference between the NPC group and the control group. In NPC patients after radiotherapy, there may be changes in the mfERGs before any visible fundus lesions appeared as radiation macular oedema. Since the global OCT macular thickness analysis cannot reveal early changes, the mfERGs can objectively and quantitatively assess the earlier changes in macular function in NPC patients.

Revealing a retinal facilitatory effect with the multifocal ERG.

We have previously shown that the amplitude of the mfERG response obtained to a single (large) hexagon is significantly smaller than that obtained when summating all the mfERG responses evoked to an array of 7-61 hexagons covering the same retinal area. The purpose of this study was to confirm our initial findings in normal subjects of different ages and in selected patients. Binocular mfERGs (1, 7, 19, 37 and 61 hexagon arrays; Espion V6.0.54 Diagnosys LLC) were recorded from 40 normal subjects (25 aged 18-25, and 15 aged 3-12). Individual mfERG waveforms evoked in response to the multi-hexagon arrays (7, 19, 37 and 61) were summated, and the amplitude of the resulting composite mfERG waveform was compared to that measured in the response evoked to the single (large) hexagon stimulus to yield the amplitude ratio (i.e., 7:1 X100, 19:1X100, etc.). In normal subjects, the 7:1 ratio was 119.5 ± 9.2%, a value that gradually decreased to reach 109.4 ± 20.6% with the 61:1 ratio and a finding that was similar across all ages. The present study indicates a significant enhancement in amplitude of the summed mfERG composite waveform evoked to the 7 hexagon stimulus array (and to a lesser extent to the 19, 37 and 61 stimuli) compared to the 1 hexagon array, possibly mediated through the retinal lateral pathway (horizontal or amacrine cells), a claim that awaits confirmation. Preliminary results obtained from patients treated with Plaquenil suggest that this new method of mfERG analysis might probe a feature of macular function different from that investigated with the more usual method of mfERG ring ratio.

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.

Comparison of ring 1 parameters in 37-segment multifocal electroretinography between onset and offset conditions of ring 2 to 4 in normal subjects.

To investigate whether the response of a central hexagonal element corresponding to the macular area in conventional multifocal electroretinography (mfERG) tests was the same as that of experimental mfERG using single central hexagonal element stimulation. Prospective, observational study. Thirty healthy subjects were included in this study. mfERG recordings were performed according to two protocols: stimulus with 37 hexagonal elements (protocol 1), and stimulus with a single central element created by deactivating the other 36 hexagonal elements (protocol 2). We compared differences between ring 1 parameters in each protocol. In protocol 1, the first positive component (P1) implicit time and P1 amplitude were 37.8±1.8ms and 6.3±2.7 µV. After single element stimulation (protocol 2), double positive waves appeared. The implicit time and amplitude of P1 were 40.7±2.4ms (P<0.001) and 9.1±3.3 µV (P=0.001), respectively. The implicit time and amplitude of the second positive component (P2) were 68.0±4.5ms (P<0.001, compared with P1 in protocol 1) and 12.3±4.7 µV (P<0.001, compared with P1 in protocol 1), respectively. The amplitude of P2 in protocol 2 was about two times higher than that of P1 in protocol 1. mfERG responses of a central hexagonal element in a single element stimulation protocol are different from those of multiple element stimulation. The positive wave is more enhanced compared to that of the conventional protocol and it elongated into two wavelets.

The Effect of Atropine on Human Global Flash mfERG Responses to Retinal Defocus.

To investigate the action of atropine on global flash multifocal electroretinogram (gmfERG) responses to retinal defocus. gmfERG recordings were made monocularly in 19 healthy adults under three lens-imposed defocus conditions (2 diopters myopic, 2 diopters hyperopic, and no defocus) before and 24 hours after instillation of 1 drop of 0.1% atropine. Signals reflecting activity from the outer and inner retina (direct [DC] and induced [IC] components respectively) were analyzed. Responses were grouped into either a central (0°-6°) or peripheral (6°-24°) retinal zone. The gmfERG responses were compared relative to the no defocus, no atropine condition. Within the central zone, atropine had no effect on the amplitudes and peak times of DC or IC responses to defocus. For IC responses in the peripheral zone, there was a significant interaction effect of atropine and defocus (F2,36 = 6.050, P = 0.011) with greater post-atropine amplitudes under myopic defocus (mean increase = 15.5%, 95% confidence interval [CI] = 5.6%-25.4%, P = 0.004). Atropine also had a significant main effect of increasing IC peak times (F1,18 = 9.722, P = 0.006). For DC responses, atropine had a significant main effect of increasing DC amplitudes (F1,18 = 7.821, P = 0.012) and peak times (F1,18 = 15.406, P = 0.001) regardless of sign of defocus. Our results imply that atropine acts in the inner layers of the peripheral retina to affect neuronal responses to myopic defocus, raising the possibility that atropine may potentiate the effects of myopic defocus in inhibiting eye growth.

Saffron therapy for the treatment of mild/moderate age-related macular degeneration: a randomised clinical trial

To assess the efficacy and safety of oral saffron, a natural antioxidant, in treating mild/moderate age-related macular degeneration (AMD). Randomised, double-blinded, placebo-controlled crossover trial of 100 adults (> 50years) with mild/moderate AMD and vision > 20/70 Snellen equivalent in at least one eye. Exclusion criteria included confounding visual lesions, or significant gastrointestinal disease impairing absorption. Participants were given oral saffron supplementation (20mg/day) for 3months or placebo for 3months, followed by crossover for 3months. Participants already consuming Age-Related Eye Diseases Study (AREDS) supplements or equivalent maintained these. Primary outcomes included changes in best-corrected visual acuity (BCVA) and changes in multifocal electroretinogram (mfERG) response density and latency. Secondary outcomes included safety outcomes and changes in mfERG and BCVA amongst participants on AREDS supplements. Mean BCVA improved 0.69 letters (p = 0.001) and mean-pooled mfERG latency reduced 0.17ms (p = 0.04) on saffron compared to placebo. Amongst participants on AREDS supplements, mean BCVA improved 0.73 letters p = 0.006) and mean-pooled mfERG response density improved 2.8% (p = 0.038). There was no significant difference in adverse event occurrence (p > 0.10). Saffron supplementation modestly improved visual function in participants with AMD, including those using AREDS supplements. Given the chronic nature of AMD, longer-term supplementation may produce greater benefits.

Multifocal Electroretinography in Diabetic Retinopathy With and Without Macular Edema.

To characterize the electroretinographic response of the macula by multifocal electroretinography (mfERG) in nonproliferative diabetic retinopathy (NPDR) with and without diabetic macular edema (DME) and correlate it with best-corrected visual acuity (BCVA) and foveal thickness on spectral-domain optical coherence tomography (SD-OCT). Prospective, observational case series. Forty eyes of 22 patients with treatment-naïve NPDR underwent recording of BCVA, fundus fluorescein angiography (FFA), and SD-OCT. Groups A and B were classified as 20 eyes each having NPDR with DME (central foveal thickness [CFT] ≥ 275 μm) and without DME (CFT < 275 μm), respectively. First-order kernel mfERG responses recorded according to ISCEV guidelines were grouped into five concentric rings centered on the fovea for analysis. Mean P1 and N1 amplitudes (nv/deg2) were significantly decreased compared to normal values in each of the five rings in both groups (P < .01); however, the values between the two groups were comparable. BCVA was significantly and positively correlated with P1 (r = 0.454, P = .003) and N1 amplitude (r = 0.468, P = .002) and significantly and negatively correlated with P1 (r= -0.534, P < .01) and N1 implicit times (r= -0.570, P < .01) in all patients. P1 (r= -0.531, P < .01) and N1 amplitude (r= -0.367, P = .02) in the central ring of mfERG had a significant negative correlation with macular thickness in the corresponding foveal ring of SD-OCT in all patients. mfERG reflects retinal dysfunction irrespective of the occurrence of DME in patients with NPDR. Correlation with BCVA reinforces that mfERG should be used to objectively assess the macular function in these patients. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:780-786.].

Higher retinal vessel oxygen saturation: investigating its relationship with macular oedema in retinitis pigmentosa patients.

Primary objective-to investigate the effect of retinal vessel oxygen saturation (SO2) on macular oedema (ME) in retinitis pigmentosa (RP) patients. Secondary objective-to link the presence of ME to metabolic (oxygen saturation of retinal vessels, SO2), functional (multifocal electroretinography, mfERG) and structural (Spectral Domain Optical Coherent Tomography, SD-OCT) alterations in RP. Prospective, cross-sectional, non-interventional study. Patients with typical RP (N = 37) and controls (N = 19), who underwent retinal vessel Oximetry (RO), SD-OCT and mfERG, were included. A computer-based program of the retinal vessel analyser unit (IMEDOS Systems UG, Jena, Germany) was used to measure SO2. We evaluated the mean SO2, in all major retinal arterioles (oxygen saturation in retinal arterioles, A-SO2, %) and venules (oxygen saturation in retinal venules, V-SO2, %). MfERG responses were averaged in zones (zone 1 (0-3°), zone 2 (3-8°) and zone 3 (8-15°)) and compared to corresponding areas of the OCT. The effect of ME on SO2 was evaluated dividing the RP in two subgroups: with clinical appearance of ME (ME-RP) and without it (no-ME-RP). Parallel recording and juxtaposition of metabolic (SO2) to structural (OCT) and functional-(mfERG) measures. Mean ( ± SD) A-SO2 and V-SO2 were higher in no-ME-RP (96.77% (±6.31) and 59.93% (±7.76)) and even higher in the ME-RP (99.82% (±6.21) and 65.63% (±7.63)), compared to controls (93.15% (±3.76) and 53.77% (±3.70), p ≤ 0.006). The subgroup ME-RP differed significantly from the subgroup no-ME-RP by increased A-SO2 and V-SO2, p ≤ 0.026. The presence of ME confirmed a different relationship between the altered SO2 and the vessel diameters, against the functional and structural parameters. Based on our results, the presence of macular oedema indicates a tendency toward greater alteration of the metabolic function in RP patients.

CHOROIDAL THICKNESS IN PATIENTS WITH STARGARDT DISEASE.

To investigate the relationship between choroidal thicknesses (CT), central foveal thicknesses, multifocal electroretinography (mf-ERG) responses, and best-corrected visual acuity levels in patients with Stargardt disease (STGD). A total of 30 eyes of 30 patients with STGD, and 30 age- and sex-matched healthy controls were included in the study. All participants underwent detailed ophthalmic examination including best-corrected visual acuity and spectral domain optical coherence tomography measurements, and also patients with STGD were performed mf-ERG. The mean subfoveal CT values were 271.95 ± 85.57 μm in patients with STGD and 355.73 ± 87.41 μm in the control group (P < 0.001). The mean central foveal thickness values were 223.56 ± 61.38 μm in patients with STGD and 272.46 ± 27.52 μm in the control group (P < 0.001). The mean central and paracentral mf-ERG responses (45.71 ± 26.60 and 16.47 ± 10.75 Nv/deg respectively) in patients with STGD were significantly lower from the normal ranges (66.6-130.8 Nv/deg and 30.9-77.7 Nv/deg, respectively; P < 0.001 for both). There was a statistically significant correlation between subfoveal CT and best-corrected visual acuity levels (P = 0.012, r = -0.452), and between parafoveal CT and inner retinal thickness and paracentral mf-ERG responses (P = 0.043, r = +0.372 and P = 0.049, r = +0.363, respectively). Paracentral mf-ERG responses were also correlated with outer retinal thickness values (P = 0.005, r = +0.503). Patients with STGD have a thinner CT, which may be responsible for some of the clinical findings. The pathophysiological significance of these findings needs further study.

Assessment of macular function in patients with idiopathic Epiretinal membrane by multifocal Electroretinography: correlation with visual acuity and optical coherence tomography

BackgroundThis study evaluates the macular function changes in patients with idiopathic macular epiretinal membrane (ERM) by multifocal electroretinography (mfERG) and their correlations with visual acuity and central macular thickness (CMT) by optical coherence tomography (OCT).MethodsTwenty eyes of 20 patients with ERM underwent OCT and mfERG examinations. The response amplitude densities and implicit times of mfERG were compared to the control fellow eyes. Correlation analyses among visual acuity, central macular thickness and mfERG values in the central two concentric rings were performed.ResultsThe mfERG P1 response amplitude densities in ring 1–2 and P1 implicit time in ring1 were significantly changed in epiretinal membrane eyes compared with controls (P < 0.05). Multivariate stepwise linear regression analyses showed LogMAR visual acuity was significantly correlated with CMT (P = 0.004), and also with the P1 amplitude density in ring 1 (P = 0.002). CMT showed significant correlation with P1 implicit time in ring 2 (P = 0.013).ConclusionsThe mfERG abnormalities show macular function changes and correlate with visual acuity and central macular thickness in eyes with ERM. In first-order mfERG responses, P1 wave changes may be a sensitive functional measurement for ERM patients.

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

PurposeTo 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.MethodsTwenty-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.ResultsBoth 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).ConclusionsStructure 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.

Clinical observation of vitrectomy combined with internal limiting membrane peeling and scleral shortening for myopic foveoschisis

Objective To observe the efficacy of vitrectomy combined with internal limiting membrane (ILM) peeling and scleral shortening for myopic foveoschisis (MF). Methods Prospective and non-randomized concurrent control study. A total of 35 MF patients (35 eyes) were enrolled in this study. The patients were divided into 2 groups according to surgery, including group A (18 eyes) and group B (17 eyes), all received vitrectomy combined with ILM peeling, but group A also received scleral shortening. The best corrective visual acuity (BCVA) examination using the Snellen vision chart was converted to the minimum resolution logarithm (logMAR). Ocular axis length (AL) was measured by Zeiss IOL-Master or A-scan ultrasound (Quantel Medical, France). The maximal value of retinal foveoschisis (MxFT) was measured by frequency-domain optical coherence tomography (Heidelberg, Germany). Multifocal electroretinogram (mfERG) responses were obtained with the RETIscan system (Roland Consult, Gemany).There was no statistically significant difference between the two groups (P>0.05) in age (t=0.460), AL (t=1.520), diopter (t=0.020), logMAR BCVA (t=−2.280), MxFT(Z=−4.179) and b-wave ERG amplitude (Z=−0.198). The changes of BCVA, AL, MxFT and b wave amplitude were followed-up for 3-12 months. Results At the last follow-up, the height of MF was decreased in 18 eyes of group A, and MF was completely disappeared in 4 eyes. The logMAR BCVA (t=7.272, 5.951), MxFT (Z=−3.724, −3.622) and b- wave ERG amplitude (Z=−3.223, −3.243) in both groups A and B were statistically improved (P=0.000, 0.000, 0.000, 0.000, 0.001, 0.001) compared to pre-operational results. There was significant difference of logMAR BCVA (t=−2.280) and MxFT (Z=−4.179) between the two groups (P=0.029, 0.000). But there was no significant difference in the amplitude of b-wave (Z=−0.198, P=0.843). The AL in group A was shortened after surgery, the difference was statistically significant (t=10.017, P=0.000). During the follow-up, there was no ocular hemorrhage, endophthalmitis and other complications. Conclusion PPV combined with ILM peeling and scleral shortening can shorten AL significantly for MF patients, and gain relative normal anatomical structure of the fovea, thus improve the vision. Key words: Myopia, degenerative/complications; Myopia, degenerative/surgery; Retinal perforations/surgery; Vitreoretinal surgery; Scleroplasty

Comparing three different modes of electroretinography in experimental glaucoma: diagnostic performance and correlation to structure.

To compare diagnostic performance and structure-function correlations of multifocal electroretinogram (mfERG), full-field flash ERG (ff-ERG) photopic negative response (PhNR) and transient pattern-reversal ERG (PERG) in a non-human primate (NHP) model of experimental glaucoma (EG). At baseline and after induction of chronic unilateral IOP elevation, 43 NHP had alternating weekly recordings of retinal nerve fiber layer thickness (RNFLT) by spectral domain OCT (Spectralis) and retinal function by mfERG (7F slow-sequence stimulus, VERIS), ff-ERG (red 0.42 log cd-s/m2 flashes on blue 30 scotopic cd/m2 background, LKC UTAS-E3000), and PERG (0.8° checks, 99% contrast, 100cd/m2 mean, 5reversals/s, VERIS). All NHP were followed at least until HRT-confirmed optic nerve head posterior deformation, most to later stages. mfERG responses were filtered into low- and high-frequency components (LFC, HFC, >75Hz). Peak-to-trough amplitudes of LFC features (N1, P1, N2) and HFC RMS amplitudes were measured and ratios calculated for HFC:P1 and N2:P1. ff-ERG parameters included A-wave (at 10ms), B-wave (trough-to-peak) and PhNR (baseline-to-trough) amplitudes as well as PhNR:B-wave ratio. PERG parameters included P50 and N95 amplitudes as well as N95:P50 ratio and N95 slope. Diagnostic performance of retinal function parameters was compared using the area under the receiver operating characteristic curve (A-ROC) to discriminate between EG and control eyes. Correlations to RNFLT were compared using Steiger's test. Study duration was 15±8months. At final follow-up, structural damage in EG eyes measured by RNFLT ranged from 9% above baseline (BL) to 58% below BL; 29/43 EG eyes (67%) and 0/43 of the fellow control eyes exhibited significant (>7%) loss of RNFLT from BL. Using raw parameter values, the largest A-ROC findings for mfERG were: HFC (0.82) and HFC:P1 (0.90); for ff-ERG: PhNR (0.90) and PhNR:B-wave (0.88) and for PERG: P50 (0.64) and N95 (0.61). A-ROC increased when data were expressed as % change from BL, but the pattern of results persisted. At 95% specificity, the diagnostic sensitivity of mfERG HFC:P1 ratio was best, followed by PhNR and PERG. The correlation to RNFLT was stronger for mfERG HFC (R=0.65) than for PhNR (R=0.59) or PERG N95 (R=0.36), (p=0.20, p=0.0006, respectively). The PhNR flagged a few EG eyes at the final time point that had not been flagged by mfERG HFC or PERG. Diagnostic performance and structure-function correlation were strongest for mfERG HFC as compared with ff-ERG PhNR or PERG in NHP EG.

Comparing ganglion cell-inner plexiform layer thickness with focal and global responses on multifocal electroretinogram in glaucoma.

BACKGROUND:The aim of this study was to evaluate responses on multifocal electroretinogram (mfERG) with ganglion cell-inner plexiform layer (GCIPL) thickness on cirrus spectral-domain optical coherence tomography (SD-OCT) in glaucoma.METHODS:All diagnosed glaucoma patients attending glaucoma services at our institute from November 2012 to April 2013 were screened for this observational hospital-based study. Controls included patients attending our outpatient services for general eye checkup. Structural parameters on SD-OCT including GCIPL and retinal nerve fiber layer (RNFL) thickness were compared with functional parameters on mfERG in early (mean deviation <−6 dB), moderate (−6 to − 12 dB), and controls.RESULTS:A total of 54 cases and 33 controls fulfilling inclusion criteria were recruited for the study. The average and minimum GCIPL thickness did not vary significantly between early and control eyes while moderate glaucoma eyes had marginally lower GCIPL thickness than early glaucoma eyes. The GCIPL minimum thickness on univariate regression was found to be influenced by N2 amplitudes (β = −0.5, P = 0.012) and global N2P1amplitudes (β =0.6, P = 0.01) in moderate glaucoma. In early glaucoma, these were influenced only by RNFL parameters with no association with functional mfERG responses. Multivariate logistic regression identified global N2P1 amplitude to be significantly influencing GCIPL average and minimum thickness (P = 0.01 and 0.02, R2 = 47.8% and 52.3%, respectively) in moderate glaucoma. Maximum area under the curve was found for GCIPL minimum (95% confidence interval [CI] 0.53–0.81) and N2P1 amplitude (95% CI 0.55–0.80).CONCLUSIONS:The second order responses N2P1 and N2 amplitude on mfERG predict function that correlated with structural GCIPL thickness in moderate glaucoma. Early glaucoma may be best predicted by RNFL thickness rather than on mfERG responses.

Multifocal Electroretinogram in normal subjects

Background: Multifocal electroretinogram (mfERG) is a device for recording the physiological response of multiple retinal areas in short time. Using this technique enables us to detect the spatial extent and severity of the retinal damage. Objectives: In this study,we aimed to assess the topographic properties of mfERG in normal subjects to use it as a basic data to evaluate eye disease. Methods: We recorded mfERG from 20 eyes of 20 normal subjects. We measured amplitude and latency of recorded waves. We compared between amplitude of these waves between different retinal areas and the same for latency. Results: We found mfERG responses in the form of waves, every wave consists of negative wave (N1) followed by positive wave (P1). The amplitude of N1 wave and amplitude of P1 were largest at the fovea and decreased toward periphery. The latency of N1 and P1 were shorter in upper retina than lower retina. The N1 amplitude and P1 amplitude was larger in upper retina than lower retina, which reflex functional superiority of upper retina. There was no statistical difference between nasal and temporal retina in the amplitude and latency.Conclusion: Multi-focal ERG would be useful for objective examination of the retinal function.

Analysis of macular sensitivity using multifocal electroretinogram and microperimetry in central serous chorioretinopathy patients after half‐dose photodynamic therapy

PurposeTo evaluate macular functional changes using multifocal electroretinography and microperimetry after half‐dose photodynamic therapy with verteporfin (HD‐PDT) in acute and chronic central serous chorioretinopathy (CSC) patientsMethodsThe charts of 101 CSC patients submitted to half‐dose PDT were reviewed. A total of 117 eyes with acute or chronic CSC underwent half‐dose PDT using 3 mg/m2 verteporfin infused over 10 min. Serial recordings of BCVA using the ETDRS charts, macular thickness using OCT and retinal sensitivity using both microperimetry (MP) and mfERG were performed at baseline and at 3, 6, 12, 18, 24, 36, 48, 60 and 72 months after treatment. A longitudinal assessment for each of these parameters and a Spearmen's correlation analysis between them was performed.ResultsCompared to baseline, a significant increase in N1, P1 and N2 mean amplitudes was registered after HD‐PDT, as well as a significant decrease in N1, P1 and N2 mean implicit times, both for central and peripheral rings. A correlation analysis showed significant correlations between BCVA and the first‐order component of retinal response for the most central ring (&lt;2°). Significant correlations were also found between P1 implicit time and mean central macular thickness both at 36 (p = 0.030) and 72 months (p = 0.037). Central 4 degrees retinal sensitivity significantly correlated with N1 amplitude ratio at 72 months (p &lt; 0.01) and P1 implicit time differences at 6 (p = 0.013) and 12 months (p = 0.014).ConclusionsmfERG demonstrated an increased retinal sensitivity in PDT‐treated CSC patients. Changes in BCVA, central macular thickness and central retinal sensitivity significantly correlated with the mfERG responses. HD PDT treatment improved both structural and functional outcomes and mfERG is an important objective parameter to evaluate functional changes in follow‐up.

Wave‐amplitude differences between corneal and conjunctival electrodes for multifocal electroretinogram

PurposeTo compare the wave amplitude of multifocal electroretinogram (mfERG) responses from DTL electrode located on the conjunctival fornix (fDTL) and ERG‐jet contact lens electrode (CL).MethodsThirty patients and 18 matched healthy volunteers were evaluated. Wave amplitude and level of discomfort with each electrode were compared in both patients and healthy volunteers. Comparisons among wave amplitudes were performed using Intraclass Correlation CoefficientResultsmfERG by corneal electrode provided the highest wave amplitude in both healthy subjects and patients (p &lt; 0.005), but it associated the highest discomfort (p &lt; 0.001) and the highest rate of dislocations. CL was able to differentiate patients from controls just in the ring 1 (central 2°) of the mfERG. By contrast, fDTL provided the lowest wave amplitude but better discriminated between patients and control group in ring 1 (central 2°) and 2 (2–5°) of the multifocal ERG. cDTL produced significant more artifacts in both groups (p &lt; 0.001).ConclusionsAlthough mfERG wave amplitude measurements 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.

Inverted Internal Limiting Membrane Flap Technique for Repair of Large Macular Holes: A Short-term Follow-up of Anatomical and Functional Outcomes.

Background:Inverted internal limiting membrane (ILM) flap technique has recently been reported in a limited number of studies as an effective surgical technique for the management of large macular holes (MHs) with fair MH closure rates as well as gains in visual acuity. In the current study, longitudinal changes in multi-focal electroretinogram (mfERG) responses, best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) were evaluated in eyes with large MHs managed by this technique.Methods:A prospective noncontrolled interventional study of eight patients (eight eyes) with large MHs (minimum diameter >400 μm) was conducted. All MHs were treated with pars plana vitrectomy and indocyanine green-assisted inverted ILM flap technique. SD-OCT images were used to assess the anatomical outcomes of surgery while BCVA and mfERG were used to evaluate the functional outcomes during a 3-month follow-up.Results:All patients underwent successful intended manipulation and translocation of the ILM flap without flap dislocation and achieved complete anatomical closure. Partial microstructural reconstruction, demonstrated on SD-OCT as restoration of the external limiting membrane and the ellipsoid zone, was observed in all cases as early as 1 month after surgery. Functionally, as compared to baseline, all patients showed improvements in BCVA and all but one in mfERG response during follow-up. However, Pearson's test revealed no significant correlations between BCVA and mfERG responses of the fovea and of the macular area at each evaluation time point.Conclusions:Inverted ILM flap technique appeares to be a safe and effective approach for the management of large idiopathic MHs with favorable short-term anatomical and functional results. Postoperative reconstruction of the microstructure generally shows good consistency with improvements in both BCVA and mfERG response, of which the latter might be a supplement for the former in postoperative functional follow-up.

Multifocal electroretinogram in non-pathological myopic subjects: correlation with optical coherence tomography

To investigate the changes of retinal function in non-pathological myopic subjects using multifocal electroretinography (mfERG) and to correlate the data with the central macular thickness obtained using optical coherence tomography (OCT). One hundred and thirteen subjects (113 eyes) with age range from 18 to 35y were enrolled in the study. The subjects were divided into four groups according to spherical equivalent (SE) and axial length (AL): emmetropia group (EG, n=31; SE: +0.75 to -0.50 D; AL: 22 to 24 mm), low and medium myopia group (LMMG, n=26; SE: >-0.50 to -6.00 D; AL: >24 to 26 mm), high myopia group (HMG, n=34; SE: >-6.00 to -10.00 D; AL: >26 to 28 mm) and super high myopia group (SHMG, n=22; SE: >-10.00 D; AL:>28 mm). The P1 amplitude density, P1 amplitude, and P1 implicit time of the first-order kernel mfERG responses were obtained and grouped into five rings. The central subfield macular thickness (CST) was obtained using macular cube 512×218 scan of Cirrus HD-OCT. With the increasing of eccentricity, the first positive peak (P1) amplitude density (P=0.0000, 0.0001, 0.0021 in ring 1-3 respectively) and P1 amplitude (all P=0.0000 in ring 1-5) of each group decreased. With the increasing of myopia, P1 implicit time gradually extended (all P=0.0000 in ring 1-3). The average CST in four diagnostic groups was 241.56±12.72 µm, 244.56±12.19 µm, 254.33±11.61 µm, 261.75±11.83 µm respectively. With the increasing of myopia, CST increased (P<0.001). There was negative relationship between CST and P1 amplitude, P1 amplitude density (r=-0.402, P<0.001; r=-0.261, P=0.003). There was positive relationship between CST and P1 implicit time (r=0.34, P<0.001). With the increasing of myopia, P1 amplitude density and P1 amplitude of the first-order reaction gradually reduced. This showed potential decline in retinal function in myopia. To some extent it may reflect the functional disorder or depression of the visual cells. The exact mechanism needs further study.

The assessment of multifocal ERG responses in school-age children with history of prematurity.

The authors examined macular function in preterm-born children, using multifocal ERG (mfERG). Possible alterations in P1 amplitudes, P1 amplitudes density and P1 implicit time between school-age children with history of prematurity and their peers were researched. The correlations between parameters of mfERG responses and birth weight, gestational age, macular volume and central macular thickness were verified. A group of 18 preterm-born school-age children were analyzed (mean age 10.18 ± 1.21 years). The study group was compared to the group of 15 peers born appropriate for gestational age (mean age 10.8 ± 1.52 years). The mfERG was evaluated in all children. There were statistically significant differences for P1 amplitudes from ring 1 (p = 0.0001) and P1 amplitudes density from ring 1 (p = 0.0001). Calculating the correlation coefficients, we receive significant results for P1 amplitudes from ring 1 versus gestational age (r = 0.54; p = 0.026), birth weight (r = 0.54; p = 0.026) and central macular thickness (r = -0.62; p = 0.008), and for P1 amplitudes density from ring 1 versus central macular thickness (r = -0.51; p = 0.034). The study suggests that P1 amplitudes and P1 amplitudes density vary in preterm-born children in comparison with their peers born appropriate for gestational age, which might suggest discreet macular dysfunction. The correlation between low birth weight, early gestational age, central macular thickness and mFERG components from ring 1 might evidence that decreased bipolar cells density caused by premature birth is the result of altered development of central retina reflecting in structural anomalies of the fovea.