The relationship between stimulus intensity and response amplitude for the photopic negative response of the flash electroretinogram.
The aim of this study was to investigate the relationship between stimulus intensity and response amplitude for the photopic negative response (PhNR) of the flash ERG. Specific aims were (i) to determine whether a generalized Naka-Rushton function provided a good fit to the intensity-response data and (ii) to determine the variability of the parameters of the best-fitting Naka-Rushton models. Electroretinograms were recorded in 18 participants, on two occasions, using both DTL fibre and skin active electrodes, in response to Ganzfeld red stimuli (Lee filter "terry red") ranging in stimulus strength from -1.30 to 0.53 log cd.s.m(-2) (0.28-2.11 log phot td.s) presented over a steady blue background (Schott glass filter BG28; 3.9 log scot td). PhNR amplitude was measured from b-wave peak and from pre-stimulus baseline. The Naka-Rushton function was fitted to all intensity-response data, and parameters, 'n', 'Vmax' and 'K' were obtained. Coefficients of variation (CoV), and inter-ocular and inter-session limits of agreement (LoA) were calculated for both Naka-Rushton parameters. A generalized Naka-Rushton function was found to provide a good fit to the intensity-response data, except at the highest stimulus intensity, where a reduction in amplitude occurred in many individuals. The 'Vmax' parameter was less variable than 'K' for all intensity-response data. Variability was lower for DTL than skin electrodes, and for peak-to-trough PhNR measurements, compared to baseline-to-trough. This study has demonstrated for the first time that the Naka-Rushton model provides a useful means of quantifying the intensity-response relationship of the PhNR.
School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff CF24 4LU, UK. BinnsAM@cf.ac.uk
A M
AM
Binns
K E
KE
Mortlock
R V
RV
North
D000328:Adult; D055253:Color Vision / Q000502:physiology*; D004566:Electrodes / Q000145:classification*; D004596:Electroretinography / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D010775:Photic Stimulation / Q000379:methods*; D055815:Young Adult
Eye (Lond). 1993;7 ( Pt 1):169-71
8325411
Invest Ophthalmol Vis Sci. 1987 Jun;28(6):954-65
3583634
Doc Ophthalmol. 1988 Mar-Apr;68(3-4):293-304
3402318
Int J Psychophysiol. 1994 May;16(2-3):137-46
8089032
Arch Ophthalmol. 1992 Nov;110(11):1571-6
1444914
Invest Ophthalmol Vis Sci. 2001 May;42(6):1266-72
11328738
Curr Eye Res. 1988 Feb;7(2):201-6
3371068
Lancet. 1986 Feb 8;1(8476):307-10
2868172
Br J Ophthalmol. 1983 Jul;67(7):419-30
6860609
Doc Ophthalmol. 1989 Oct;73(2):173-81
2638626
Appl Opt. 1989 Mar 15;28(6):1145-50
20548633
Exp Eye Res. 2004 Jan;78(1):83-93
14667830
BMJ. 1995 Jan 21;310(6973):170
7833759
Invest Ophthalmol Vis Sci. 2004 Oct;45(10):3827-37
15452095
Invest Ophthalmol Vis Sci. 1994 Apr;35(5):2477-88
8163337
Invest Ophthalmol Vis Sci. 2004 Mar;45(3):1033-40
14985327
Invest Ophthalmol Vis Sci. 2008 May;49(5):2201-7
18436853
Doc Ophthalmol. 2004 Jan;108(1):99-106
15104172
Invest Ophthalmol Vis Sci. 2000 Jul;41(8):2205-11
10892864
Arch Ophthalmol. 2004 Mar;122(3):341-6
15006846
Optom Vis Sci. 2008 Jun;85(6):386-95
18521020
Jpn J Ophthalmol. 2006 Jul-Aug;50(4):367-373
16897223
Dev Ophthalmol. 1984;9:133-9
6526100
Invest Ophthalmol Vis Sci. 2001 Feb;42(2):514-22
11157891
Doc Ophthalmol. 2006 Jul;113(1):53-9
16944088
Invest Ophthalmol Vis Sci. 1987 Jan;28(1):140-50
3804644
Doc Ophthalmol. 2009 Jun;118(3):167-77
18932006
Invest Ophthalmol Vis Sci. 2007 Oct;48(10):4818-28
17898309
Doc Ophthalmol. 2001 Mar;102(2):115-30
11518455
Doc Ophthalmol. 2002 May;104(3):231-48
12076014
Doc Ophthalmol. 2008 Jul;117(1):37-46
18026866
Graefes Arch Clin Exp Ophthalmol. 1984;222(1):29-33
6510722
Jpn J Ophthalmol. 2000 Jan-Feb;44(1):20-8
10698021
Doc Ophthalmol. 1992;80(4):335-45
1473449
Vision Res. 2005 Aug;45(17):2321-30
15924945
Invest Ophthalmol Vis Sci. 1999 May;40(6):1124-36
10235545
Invest Ophthalmol Vis Sci. 1979 Sep;18(9):988-91
478786
Vision Res. 1978;18(7):793-800
676087
Doc Ophthalmol. 1993;85(2):135-50
7521824
Doc Ophthalmol. 2010 Oct;121(2):123-34
20607349
Doc Ophthalmol. 1991;76(4):367-75
1935545
Doc Ophthalmol. 1984 May 30;57(3):279-96
6468246
Doc Ophthalmol. 1992;80(1):1-11
1505334
Doc Ophthalmol. 1997-1998;94(4):327-40
9858093
Doc Ophthalmol. 2004 Jul;109(1):43-55
15675199
Vision Res. 2003 Jun;43(12):1405-12
12742110
Jpn J Ophthalmol. 2008 Jul-Aug;52(4):327-330
18773273
Am J Ophthalmol. 2004 May;137(5):938-40
15126164
Vision Res. 1999 Mar;39(6):1069-70
10343826