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Comparison of DTL and gold cup skin electrodes for recordings of the multifocal electroretinogram. Doc Ophthalmol 2023; 146:67-78. [PMID: 36536110 PMCID: PMC9911471 DOI: 10.1007/s10633-022-09912-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/11/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To compare mfERG recordings with the Dawson-Trick-Litzkow (DTL) and gold cup skin electrode in healthy young and old adults and to test the sensitivity of both electrodes to age-related changes in the responses. METHODS Twenty participants aged 20-27 years ("young") and 20 participants aged 60-75 ("old") with a visual acuity of ≤ 0 logMAR were included. The mfERG responses were recorded simultaneously using DTL and skin electrodes. P1 amplitudes, peak times and signal-to-noise ratios (SNRs) were compared between both electrodes and across age groups, and correlation analyses were performed. The electrode's performance in discriminating between age groups was assessed via area under curve (AUC) of receiver operating characteristics. RESULTS Both electrodes reflected the typical waveform of mfERG recordings. For the skin electrode, however, P1 amplitudes were significantly reduced (p < 0.001; reduction by over 70%), P1 peak times were significantly shorter (p < 0.001; by approx. 1.5 ms), and SNRs were reduced [(p < 0.001; logSNR ± SEM DTL young (old) vs gold cup: 0.79 ± 0.13 (0.71 ± 0.15) vs 0.37 ± 0.15 (0.34 ± 0.13)]. All mfERG components showed strong significant correlations (R2 ≥ 0.253, p < 0.001) between both electrodes for all eccentricities. Both electrodes allowed for the identification of age-related P1 changes, i.e., P1-amplitude reduction and peak-time delay in the older group. There was a trend to higher AUC for the DTL electrode to delineate these differences between age groups, which, however, failed to reach statistical significance. CONCLUSIONS Both electrode types enable successful mfERG recordings. However, in compliant patients, the use of the DTL electrode appears preferable due to the larger amplitudes, higher signal-to-noise ratio and its better reflection of physiological changes, i.e., age effects. Nevertheless, skin electrodes appear a viable alternative for mfERG recordings in patients in whom the use of corneal electrodes is precluded, e.g., children and disabled patients.
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Smith JD, Jussel A, Wang R, Coates DR, Harrison WW. Fundus motion during mfERG testing. Doc Ophthalmol 2021; 143:129-139. [PMID: 33713340 DOI: 10.1007/s10633-021-09829-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 02/26/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE The purpose of this study was to assess eye movements during a multifocal ERG (mfERG) recording. This study evaluated the relationship between bivariate contour ellipse areas (BCEAs), mfERG amplitudes (Amps) and mfERG implicit times (ITs) with repeat testing and experienced subjects. METHODS Thirty subjects were selected (15 experienced to ocular procedures and 15 novices). All were confirmed to have healthy retinas and at least 20/25 vision. MfERGs with a stimulus near 100% contrast and 4-min m-sequence were recorded on two different days using our common clinical technique, which did not constrain the head. VERIS with fundus monitoring system was used for recording with a Burian-Allen electrode. An external camera captured the fundus during each mfERG recording. The optic nerve head position was tracked in each video using a custom algorithm in order to determine BCEAs. Each subject performed one mfERG on two different days. MfERGs were analyzed for Amps and ITs for the fovea and whole eye. RESULTS There was no correlation between the mfERG metrics and BCEAs with repeat testing. There were also no differences between the experienced and novice subjects for mfERG Amps, ITs or BCEAs. Eye movements between visits were highly correlated (multiple r = 0.67). BCEAs were larger during mfERGs (1.04 ± 0.8 deg2) than those observed in previous literature using brief viewing tasks (< 0.3 deg2). The proportion of time spent fixating within 1.0 and 2.0 degrees of the central hexagon was 68 and 93%, respectively. CONCLUSIONS This study is the first to evaluate the stability of the retina while recording a mfERG in healthy subjects and indicates that the center of fixation during a mfERG stays within the central hexagon. Eye stability during an initial recording is the best indicator of stability on the second recording. The amount of movement during these recordings did not seem to affect the mfERG Amps or ITs. These data suggest clinical confidence with mfERGs when recording novice patients.
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Affiliation(s)
| | - Allison Jussel
- University of Houston College of Optometry, Houston, TX, USA
| | - Rachel Wang
- University of Houston College of Optometry, Houston, TX, USA
| | - Daniel R Coates
- University of Houston College of Optometry, Houston, TX, USA
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Muranyi DS, Kramer FH, Herbik A, Hoffmann MB. Scotopic multifocal visual evoked potentials. Clin Neurophysiol 2019; 130:379-387. [PMID: 30677707 DOI: 10.1016/j.clinph.2018.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 11/24/2018] [Accepted: 11/27/2018] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To investigate the scope of scotopic multifocal visual evoked potentials (mfVEPS) for the assessment of scotopic visual fields. METHODS Pattern-reversal mfVEP for photopic (mfVEPP) and scotopic conditions (mfVEPS; 0.003 cd/m2) were recorded from 36 visual field locations of a circular checkerboard pattern (25° radius) in 9 participants with normal vision. MfVEPP were recorded with a conventional central fixation cross, mfVEPS were recorded (i) with (mfVEPS+) and (ii) without (mfVEPS-) an additional fixation aid. Latency shifts were determined using cross-correlations, mfVEP magnitudes were analysed in an eccentricity dependent manner using signal-to-noise ratios (SNRs). RESULTS In comparison to mfVEPP, mfVEPS- and mfVEPS+ were delayed by 101 ms and 97 ms, respectively, and had smaller signal-to-noise-ratios. Both mfVEPS were reduced down to noise level in the center and also severely reduced for the most peripheral stimulus eccentricity used. The visual-field-coverage for the paracentral eccentricities of mfVEPS+ and mfVEPS- was 76% and 65% [4°-9°], respectively, and 79% and 66% [9°-16°]. CONCLUSIONS MfVEPS were delayed compared to mfVEPP and demonstrated the expected central response drop-out typical for scotopic vision. SIGNIFICANCE MfVEPS may hold promise of an objective, spatially resolved visual field test which motivates testing it in patients with diseases affecting scotopic vision.
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Affiliation(s)
- D S Muranyi
- Department of Ophthalmology, Otto-von-Guericke University Magdeburg, Germany; Department of Ophthalmology, Martin-Luther University Halle, Germany
| | - F H Kramer
- Department of Ophthalmology, Otto-von-Guericke University Magdeburg, Germany; Beuth University of Applied Sciences, Berlin, Germany
| | - A Herbik
- Department of Ophthalmology, Otto-von-Guericke University Magdeburg, Germany
| | - M B Hoffmann
- Department of Ophthalmology, Otto-von-Guericke University Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany.
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Pedersen KB, Sjølie AK, Vestergaard AH, Andréasson S, Møller F. Fixation stability and implication for multifocal electroretinography in patients with neovascular age-related macular degeneration after anti-VEGF treatment. Graefes Arch Clin Exp Ophthalmol 2016; 254:1897-1908. [PMID: 27080862 DOI: 10.1007/s00417-016-3323-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 03/02/2016] [Accepted: 03/09/2016] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To quantify fixation stability in patients with neovascular age-related macular degeneration (nAMD) at baseline, 3 and 6 months after anti-vascular endothelial growth factor (anti-VEGF) treatment and furthermore asses the implications of an unsteady fixation for multifocal electroretinography (mfERG) measurements. METHODS Fifty eyes of 50 nAMD patients receiving intravitreal anti-VEGF treatment with either bevacizumab or ranibizumab and eight eyes of eight control subjects were included. Fixation stability measurements were performed with the Eye-Link eyetracking system and the retinal area in degrees2 (deg2) containing the 68 % most frequently used fixation points (RAF68) was calculated. MfERG P1 amplitude and implicit time were analyzed in six concentric rings and as a summed response. Patients were examined at baseline, 3 and 6 months. Four different mfERG recordings were performed for the control subjects to mimic an involuntary unstable fixation: normal central fixation, 2.4°, 4.8°, and 7.1° fixation instability. RESULTS For control subjects, a fixation instability of 2.4° (corresponding to the central hexagon) did not reduce mfERG ring amplitudes significantly, whereas 4.8° and 7.1° fixation instability reduced the amplitudes significantly in rings 1 and 2 (p < 0.001) as well as in the peripheral rings in the 7.1° instability condition (p < 0.001). Fixation stability improved non-significantly for patients at 3 and 6 months. The size of the retinal area of fixation was at baseline, 3 and 6 months negatively correlated to visual acuity (VA) (rbaseline = -0.65, r3 months = -0.60, and r6 months = -0.66 respectively, p < 0.001) and mfERG amplitudes of the three innermost rings (rbaseline = -0.29, p = 0.042, r3 months = -0.43, p = 0.003 and r6 months = -0.31, p = 0.042). The VA cutoff for a fixation area less than 5 deg2 (approximately the central hexagon) was 65, 77, and 68 ETDRS letters (corresponding a maximal Snellen equivalent of 0.31) at baseline, 3 and 6 months, respectively. CONCLUSIONS MfERG amplitudes in recordings of nAMD patients are at substantial risk of being reduced due to poor fixation as a large number of patients may use a fixation area of more than 5 deg2. Fixation monitoring during recording as well as interpretation of results should be performed with care, especially in patients with poor visual acuity.
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Affiliation(s)
- K B Pedersen
- Department of Ophthalmology, Rigshospitalet-Glostrup, Nordre Ringvej 57, 2600, Glostrup, Denmark.
| | - A K Sjølie
- Department of Ophthalmology, Odense University Hospital, 5000, Odense, Denmark
| | - A H Vestergaard
- Department of Ophthalmology, Odense University Hospital, 5000, Odense, Denmark
| | - S Andréasson
- Department of Ophthalmology, Lund University, 221 00, Lund, Sweden
| | - F Møller
- Department of Ophthalmology, Vejle Hospital, 7100, Vejle, Denmark
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Kim JW, Choi YJ, Lee SY, Choi KS. Clinical usefulness of binocular multifocal electroretinography in patients with monocular macular disease. KOREAN JOURNAL OF OPHTHALMOLOGY 2013; 27:261-7. [PMID: 23908572 PMCID: PMC3730068 DOI: 10.3341/kjo.2013.27.4.261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 11/08/2012] [Indexed: 11/23/2022] Open
Abstract
Purpose To evaluate the clinical usefulness of binocular multifocal electroretinography (mfERG) by comparing results with conventional monocular mfERG in patients with monocular macular disease. Methods mfERG testing was conducted on 32 patients with monocular macular disease and 30 normal subjects. An initial mfERG was simultaneously recorded from both eyes with two recording electrodes under binocular stimulation. A second mfERG was subsequently recorded with conventional monocular stimulation. Amplitudes and implicit times of each ring response of the binocular and monocular recordings were compared. Ring ratios of the binocular and monocular recording were also compared. Results In the macular disease group, there were no statistical differences in amplitude or implicit time for each of the five concentric rings between the monocular and binocular recordings. However, with binocular simulation, the ring ratios (ring 1 / ring 4, ring 1 / ring 5) were significantly reduced in the affected eye. In the normal control group, there were no statistical differences in any parameters between the monocular and binocular recordings. Conclusions Binocular mfERG could be a good alternative to the conventional monocular test. In addition, given that the test needs stable fixation of the affected eye during the binocular test, the reliability of the test results could be improved, especially for patients with monocular macular disease.
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Affiliation(s)
- Jee Wook Kim
- Department of Ophthalmology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea
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The value of two-field pattern electroretinogram in routine clinical electrophysiologic practice. Retina 2012; 32:588-99. [PMID: 21878848 DOI: 10.1097/iae.0b013e31822059ae] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the clinical use of the large-field pattern electroretinogram (PERG) as an adjunct test to the International-standard PERG in an unselected sequential cohort of patients referred for routine electrophysiologic assessment. METHODS Pattern electroretinograms to both 15° × 11° (International Society for Clinical Electrophysiology of Vision Standard) and 30° × 22° (large field) checkerboard field sizes were recorded in 277 consecutive electrophysiology patients, aged 10-79 years. Most patients had additional tests including full-field electroretinogram, electrooculogram, multifocal electroretinograms, or cortical visual evoked potential. Patient data were compared with data from 27 control subjects. RESULTS Satisfactory 2-field PERG data were obtained in 91% (N = 253) of patients; data from 24 patients (9%) were excluded because of poor compliance (n = 17) or nystagmus (n = 7). Standard PERGs were consistent with macular dysfunction in 44% of cases; large-field PERG revealed macular dysfunction in an additional 8% of eyes and helped to distinguish between localized central, predominantly paracentral, and widespread macular dysfunction. The results were consistent with multifocal electroretinogram and/or imaging studies on the same patients. In some patients with optic nerve disease, the large-field PERG provided clearer evidence of normal macular function than the standard PERG. CONCLUSION Routine use of the large-field PERG is a valuable complement to standard-field PERG testing in the evaluation and management of patients with different forms of macular or generalized retinal dysfunction and can be useful in patients with optic nerve disease.
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Pálffy A, Janáky M, Fejes I, Horváth G, Benedek G. Interocular amplitude differences of multifocal electroretinograms obtained under monocular and binocular stimulation conditions. ACTA ACUST UNITED AC 2010; 97:326-31. [DOI: 10.1556/aphysiol.97.2010.3.9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Mendoza-Santiesteban CE, Fernández-Cherkasova L, Echavarria OH, Rodríguez RC, Columbié-Garbey Y, Riesgo TJ. Multifocal electroretinography. Semin Ophthalmol 2010; 25:155-64. [PMID: 20695736 DOI: 10.3109/08820538.2010.500210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Multifocal electroretinography (mfERG) provides functional and objective evidence of retinal dysfunction. We have found mfERG to be especially useful in the management of occult outer retinopathy and Stargardt's disease.
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Tam WK, Chan H, Brown B, Leung KW, Woo V, Yap M. Comparing the Multifocal Electroretinogram Topography before and after Cataract Surgery. Curr Eye Res 2009; 30:593-9. [PMID: 16020294 DOI: 10.1080/02713680590968565] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To investigate whether multifocal electroretinogram (mfERG) topography would be affected by nuclear cataract. METHODS Multifocal electroretinograms were recorded from 10 elderly subjects (10 eyes) with nuclear cataract of grade five (LOCS III) before and after cataract surgery (phacoemulsification). Their visual acuity before the cataract surgery was between 6/12 and 6/18. The postoperative period was from 2 to 3 months. None of the subjects had any significant eye disease apart from cataract. The mfERG responses were grouped into six concentric rings for analysis. Both the amplitudes and the latencies of N1 and P1 of first-order responses were used for analysis. RESULTS N1 amplitude only from ring 1 increased significantly after cataract surgery. P1 amplitude from ring 1 and ring 2 also increased significantly after cataract surgery. The latencies of neither N1 nor P1 from all rings changed significantly. CONCLUSIONS Nuclear cataract could affect the topography of mfERG, so clinicians should be aware of the effects of cataract when interpreting mfERG responses in cataract patients.
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Affiliation(s)
- Wing-Kin Tam
- Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hong Kong
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Lai TYY, Chan WM, Lai RYK, Ngai JWS, Li H, Lam DSC. The clinical applications of multifocal electroretinography: a systematic review. Surv Ophthalmol 2007; 52:61-96. [PMID: 17212991 DOI: 10.1016/j.survophthal.2006.10.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Multifocal electroretinography (mfERG) is an investigation that can simultaneously measure multiple electroretinographic responses at different retinal locations by cross-correlation techniques. mfERG therefore allows topographic mapping of retinal function in the central 40-50 degrees of the retina. The strength of mfERG lies in its ability to provide objective assessment of the central retinal function at different retinal areas within a short duration of time. Since the introduction of mfERG in 1992, mfERG has been applied in a large variety of clinical settings. This article reviews the clinical applications of mfERG based on the currently available evidence. mfERG has been found to be useful in the assessment of localized retinal dysfunction caused by various acquired or hereditary retinal disorders. The use of mfERG also enabled clinicians to objectively monitor the treatment outcomes as the changes in visual functions might not be reflected by subjective methods of assessment. By changing the stimulus, recording, and analysis parameters, investigation of specific retinal electrophysiological components can be performed topographically. Further developments and consolidations of these parameters will likely broaden the use of mfERG in the clinical setting.
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Affiliation(s)
- Timothy Y Y Lai
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
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Chu PHW, Chan HHL, Leat SJ. Effects of unsteady fixation on multifocal electroretinogram (mfERG). Graefes Arch Clin Exp Ophthalmol 2006; 244:1273-82. [PMID: 16550403 DOI: 10.1007/s00417-006-0304-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 02/02/2006] [Accepted: 02/04/2006] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To investigate the effect of unsteady fixation on the multifocal electroretinogram (mfERG) measurement in normal subjects. METHODS The mfERGs of 20 subjects with normal vision (mean age=23.5 years) were recorded with different levels of voluntary eye movements made to mimic unsteady fixation. Subjects were required to move their fixation regularly every 2 s between the center and the ends of a fixation cross, so that 51.2% of the time fixation was at the center and 12.2% of the time it was at each end of the fixation cross. Four different conditions were performed: central fixation (without voluntary eye movements) and with 2 degrees, 4 degrees and 6 degrees magnitude of unsteady fixation. First-order kernel mfERG findings are presented. RESULTS Analysis of the ring responses indicated that the central mfERG amplitude was most affected by unsteady fixation. There was significantly reduced amplitude for 4 degrees unsteady fixation and as expected, this reduction became larger with 6 degrees unstable fixation. However, there was no significant effect on the center hexagon amplitude for 2 degrees unsteady fixation. The amplitudes of the ring-2 responses were only affected in the 6 degrees unsteady fixation condition. No significant change in implicit time was found for any level of unsteady fixation. CONCLUSION These results suggest that mfERG amplitude is not substantially affected if fixation is maintained within the central stimulus hexagon. We conclude that, for patients with poor fixation, the accuracy of mfERG results may be difficult to interpret and the use of a fixation-monitoring system is desirable for ideal measurement. The depth of depression at the blind spot area may be another useful parameter to interpret the accuracy of mfERG results in patients with poor fixation.
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Affiliation(s)
- Patrick H W Chu
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, SAR, People's Republic of China
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Bellmann C, Feely M, Crossland MD, Kabanarou SA, Rubin GS. Fixation stability using central and pericentral fixation targets in patients with age-related macular degeneration. Ophthalmology 2004; 111:2265-70. [PMID: 15582084 DOI: 10.1016/j.ophtha.2004.06.019] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Accepted: 06/11/2004] [Indexed: 10/26/2022] Open
Abstract
PURPOSE To determine fixation stability for central and pericentral fixation targets in patients with age-related macular degeneration (AMD). DESIGN Comparative study. PARTICIPANTS Twelve patients having late-stage AMD involving the fovea and 10 age-matched controls having no other eye diseases and visual acuity better than 20/25. METHODS Six different fixation targets (1 degrees cross; 1 degrees filled circle; 1 degrees letter x; small 4-point diamond; large 4-point diamond using dimensions as in a field analyzer; large-crossover whole-image diagonal with open 1 degrees center) were presented on a high-resolution monitor. Before examination, subjects were given verbal instructions to move their eye to see the center of the target best. Fixation stability was measured for the preferred eye, with the fellow eye occluded, using a gaze tracker. Fixation stability was quantified by calculating the bivariate contour ellipse area (BCEA) over 30 seconds for each target. For statistical analysis, BCEA values (minutes of arc2) were converted into their logarithms. The absolute retinal scotoma for the study eye was determined using a scanning laser ophthalmoscope. MAIN OUTCOME MEASURE Bivariate contour ellipse area. RESULTS Visual acuity in patients (age range, 57-87 years) ranged from 20/32 to 20/600. The lowest BCEA values were found for the 1 degrees letter x in patients (mean, 12052.2%+/-254.0%) and for the 1 degrees cross in normal subjects (mean, 1286.9%+/-47.8%); the highest BCEA values were found for the small 4-point diamond in patients (mean, 23109.5%+/-298.3%) and for the large 4-point diamond in normals (age range, 62-79 years) (mean, 3229.2%+/-105.4%). The difference between the targets was significant for normal subjects (analysis of variance [ANOVA], P<0.01) but not for patients (ANOVA, P>0.05). In normals, BCEA values were significantly lower for central fixation targets than for pericentral fixation targets (P<0.01). CONCLUSION Fixation is significantly less stable for pericentral fixation targets in normal subjects, indicating an advantage for central fixation targets. These results are particularly significant for any clinical and experimental testing method that requires the patient to maintain stable fixation.
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Bellmann C, Neveu MM, Kousoulides L, Sloper JJ, Bird AC, Holder GE. Potential diagnostic dilemmas using the multifocal electroretinogram in intermittent exotropia. Br J Ophthalmol 2004; 88:1223-4. [PMID: 15317720 PMCID: PMC1772306 DOI: 10.1136/bjo.2003.040584] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Vrabec TR, Affel EL, Gaughan JP, Foroozan R, Tennant MTS, Klancnik JM, Jordan CS, Savino PJ. Voluntary suppression of the multifocal electroretinogram. Ophthalmology 2004; 111:169-76. [PMID: 14711730 DOI: 10.1016/j.ophtha.2003.04.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2002] [Accepted: 04/04/2003] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To describe multifocal electroretinogram (mfERG) responses in 2 patients with nonorganic visual loss and in 11 eyes of 6 healthy persons who suppressed their mfERG responses. DESIGN Observational case series. METHODS The mfERG results were recorded in all individuals using the Veris Science 4.2 instrument. All subjects were instructed to adjust the hexagonal test pattern so that it was in best focus. A second mfERG was recorded subsequently in volunteers who attempted suppression with inattention and poor fixation and by adjusting the focus to greatest blur. MAIN OUTCOME MEASURES Amplitude and latency of mfERG responses. RESULTS Suppressed mfERGs in patients with nonorganic visual loss and healthy volunteers demonstrated reduced amplitude, especially centrally. Amplitude reduction was statistically significant in the postsuppression as compared with the presuppression recordings in wave forms N1 and N2. Statistically significant shortening of postsuppression implicit times of P1 and N2 waveforms also was demonstrated. CONCLUSIONS The mfERG responses may be suppressed voluntarily. Amplitude may be reduced. In contrast to most reported pathologic conditions, the implicit time is shortened.
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Affiliation(s)
- Tamara R Vrabec
- Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Rudolph G, Kalpadakis P, Bechmann M, Haritoglou C, Kampik A. Scanning laser ophthalmoscope-evoked multifocal ERG (SLO-mfERG) in patients with macular holes and normal individuals. Eye (Lond) 2003; 17:801-8. [PMID: 14528241 DOI: 10.1038/sj.eye.6700502] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIMS A scanning laser ophthalmoscope (SLO) has been used for multifocal electroretinography (mf ERG) measurements under simultaneous fundus monitoring. The aim of this study was to prove if the SLO-mfERG measurement reflects reliably the clinically registered underlying disease, and to demonstrate the importance of its main advantage, fixation monitoring. METHODS In all, 10 patients with macular hole stage II/III were included in the study, and 19 normal individuals served as the control group. The mf ERG device was combined with an SLO, which was used both as a stimulus and trigger unit as well as a fundus-monitoring system. Monitoring of the fundus was guaranteed by an infrared laser (780 nm). The stimulus matrix consisted of 61 hexagonal elements, covering 24 degrees of the posterior pole. We examined both, patients with macular holes and healthy individuals. RESULTS Compared to normal controls, patients with a macular hole (Gass stage III) showed a significant decrease in response density in the centre of the stimulus array, which correlated well with the morphological alteration observed by clinical examination. However, variation of response density of the central hexagonal area has been proved to be high. CONCLUSIONS SLO-mfERG is a feasible and reliable new technique to investigate macular function under simultaneous fundus control. The main advantage is that control of fixation can be used in order to obtain more reliable results that correlate well with visible fundus abnormalities such as in patients with macular holes. However, further investigations have to be performed in order to overcome sufficiently the problem of fixation instability.
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Affiliation(s)
- G Rudolph
- Eye Clinic, Ludwig-Maximilians-University Munich, Germany.
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Rudolph G, Kalpadakis P. Topographic mapping of retinal function with the SLO-mfERG under simultaneous control of fixation in Best's disease. Ophthalmologica 2003; 217:154-9. [PMID: 12592056 DOI: 10.1159/000068560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2002] [Accepted: 10/17/2002] [Indexed: 11/19/2022]
Abstract
PURPOSE To introduce the scanning laser ophthalmoscope-evoked mfERG (SLO-mfERG) as a new method to measure focal retinal function. METHODS Sixty-two healthy individuals and 12 patients with Best's disease were examined. mfERGs were recorded using a scanning laser ophthalmoscope as a stimulator and trigger device (He-Neon 632.8 nm) as well as a fundus-monitoring system (Infrared 730 nm). RESULTS Amplitudes in the central concentric area were found to be significantly lower in patients with Best's disease than in healthy controls, while no significant differences were found for the more peripheral areas. CONCLUSION SLO-mfERG is a reliable new technique for topographic mapping of retinal function under simultaneous control of fixation.
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