Purchase this article with an account.
S.M. Ronan, S. Nusinowitz, J.R. Heckenlively; Subgroup of Age–Related Macular Degeneration Demonstrates Panretinal Cone Dysfunction . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2127.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We investigated if standardized electroretinography (ERG) could be used to distinguished different groups in age–related macular degeneration (AMD.) Rod and cone function was studied in AMD patients and compared to age–matched controls without AMD.
This a retrospective study evaluating ERG studies that were performed in senior citizens with AMD who volunteered to help research over a 12 year period. Fifty–three individuals were found to be 60 years of age or older with a diagnosis of AMD, documentation of standardized ERG values, and fundus photographs. The age range of our study group was 61–93 years old with a mean of 74.4 years. A normal control group was generated who were elderly and did not have AMD. The photopic, scotopic, dark–adapted bright flash, and flicker function responses were compared between the two groups.
We found a distinct group of AMD patients who have abnormal ERGs. In general, the majority of test amplitudes are lower in the study group than the controls, and many have much longer implicit times. The most pronounced differences were seen with the bright flash dark–adapted a–waves and the photopic b–wave amplitudes. The mean of the photopic b–wave amplitudes for the study group was 76.18µV with a standard deviation of 35.21µV. The mean of the photopic b–wave amplitudes for the control group was 90.16µV with a standard deviation of 17.43µV. This finding was statistically significant with a P–value of 0.05 by the Wilcoxon test.
There is a subgroup of AMD patients that have panretinal cone dysfunction in association with their macular degeneration as shown on electroretinography. Some patients also have distinct abnormal scotopic responses. Previous studies have shown varied results when looking at ERG changes in AMD, and likely reflect the underlying complexity of this disorder. Using standardized ERG to identify a more homogeneous subgroup of AMD such as those with a panretinal cone dysfunction will be valuable for assisting better clinical characterization of AMD subtypes clinically and the underlying genetic basis for them. The a–wave response in the dark–adapted bright flash ERG may be an additional method for identifying AMD patients with abnormal ERG responses.
This PDF is available to Subscribers Only