Abstract
The mfERG has proven to be a useful tool in determining central retinal and macular function. It is, however, reliant on good subject co-operation and fixation. This cannot always be guaranteed due to visual impairment or poor co-operation. Whilst a change in fixation is easy to identify with camera monitoring of the subject, a small eccentric fixation can be difficult to notice or quantify. Whilst the problem of fixation can be obviated by stimulating the retina directly with SLO (Scanning Laser Ophthalmoscope), this is expensive and a certain amount of expertize in optics is required to properly stimulate the retina. In this study, peak latency of response was investigated to see whether it changed across the retina and whether this measure could be used to help assess fixation. Eighteen normal eyes were stimulated using a 60 Hz CRT monitor with only 2 hexagons, one central and one peripheral. These hexagons were presented at three stimulation rates, fast (no filler frames between steps of the m-sequence) and slow (4 and 7 black filler frames between each step of the m-sequence), under all conditions significantly increased central hexagon latencies were noted. In a smaller experiment with 19 hexagons and only 4 subjects, it was noted a significant delay in latency was observed in ring 1 compared to ring 2 and 3 with central fixation, but not when the subjects fixed mid-peripheral and in the periphery to slow stimulation, showing that the central hexagon response was only delayed in the central hexagon when there was adequate fixation. This study suggests that latency could provide a clue to fixation particular at slow rates thereby improving the quality and confidence of recordings made clinically.
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References
Osterberg G (1935) Topography of the layer of rods and cones in the human retina. Acta Ophthalmologica 13:11–96
Curcio CA, Sloan KR, Kalina RE, Hendrickson AE (1990) Human photoreceptor topography. J Comp Neurol 292:497–523
Holder GE (1987) Significance of abnormal pattern electroretinography in anterior visual pathway dysfunction. Br J Ophthalmol 71:166–171
Miyake Y, Awaya S (1984) Stimulus deprivation amblyopia: simultaneous recording of local macular electroretinogram and visual evoked response. Arch Ophthalmol 102:998–1003
Sandberg MA, Jacobson SG, Berson EL (1979) Foveal cone electroretinograms in retinitis pigmentosa and juvenile macular degeneration. Am J Ophthalmol 88:702–707
Sutter EE (1991) The fast m-transform: a fast computation of cross-correlations with binary m-sequences. Soci Indus Appl Math J Comput 20:686–694
Sutter EE, Tran D (1992) The field topography of ERG components in man-I. The photopic luminance response. Vis Res 32:433–446
Sutter EE (1985) Multi-input VER and ERG analysis for objective perimetry. Proceedings of the seventh annual conference of engineering and medical society pp 414–419
Lai TYY, Chan WM, Lai RYK, Ngai JWS, Li H, Lam DSC (2007) The clinical applications of multifocal electroretinography: a systematic review. Surv Ophthalmol 52:61–96
Dolan FM, Parks S, Hammer H, Keating D (2002) The wide field electroretinogram reveals retinal dysfunction in early retinitis pigmentosa. Br J Ophthalmol 86:480–481
Seiple W, Clemens CJ, Greenstein VC, Carr RE, Holopigian K (2004) Test-retest reliability of the multifocal electroretinogram and Humphrey visual fields patients with retinitis pigmentosa. Doc Ophthalmol 109:255–272
McDonagh J, Stephen LJ, Dolan FM, Parks S, Dutton GN, Kelly K, Keating D, Sills GJ, Brodie MJ (2003) Peripheral retinal dysfunction in patients taking vigabatrin. Neurology 61:1690–1694
Bultmann S, Rohrschneider K (2002) Reproducibility of multifocal ERG using the scanning laser ophthalmoscope. Graefe’s Arch Clin Exp Ophthalmol 240:841–845
Rudolph G, Kalpadakis P, Ehrt O, Berninger T, Kampik A (2003) Scanning laser ophthalmoscope multifocal elecetroretinography and microperimetry in patients with Stargardt’s disease. Ophthalmologe 100:720–726
Rudolph G, Kalpadakis P (2003) Topographic mapping of retinal function with the SLO-mfERG under simultaneous control of fixation in Best’s disease. Ophthalmologica 217:154–159
Nagatomo A, Nao-i N, Maruiwa F, Arai M, Sawada A (1998) Multifocal electroretinograms in normal subjects. pp 129–135
Schimitzek T, Bach M (2006) The influence of luminance on the multifocal ERG. Doc Ophthalmol 113:187–192
Hood DC, Seiple W, Holopigian K, Greenstein VC (1997) A comparison of the components of the multifocal and full-field ERGs. Vis Neurosci 14:533–544
Bock M, Andrassi M, Belitsky L, Lorenz B (1999) A comparsion of two multifocal ERG systems. Doc Ophthalmol 97:157–178
Rangaswamy NV, Hood DC, Frishman LJ (2003) Regional variations in local contributions to the primate photopic flash ERG: revealed using the slow-sequence mfERG. Invest Ophthalmol Vis Sci 44:3233–3247
Boycott BB, Hopkins JM, Sperling HG (1987) Cone connections of the horizontal cells of the rhesus monkey’s retina. Proc R Soc 229:345–379
Perry VH, Cowey A (1988) The length of the fibers of Henle in the retina of macaque monkeys: implications for vision. Neurosci 25:225–236
Schein SJ (1988) Anatomy of macuque fovea and spatial densities of neurons in foveal representation. J Comp Neurol 1988:479–505
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Hagan, R.P., Small, A., Fisher, A.C. et al. Can central hexagon peak latency provide a clue to fixation within the mfERG. Doc Ophthalmol 120, 159–164 (2010). https://doi.org/10.1007/s10633-009-9206-5
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DOI: https://doi.org/10.1007/s10633-009-9206-5