W-K Tam | PubMed Health

PubMed2006

Aging and mfERG topography.

AIM: To study the effect of aging retina on the multifocal electroretinogram (mfERG). METHODS: A total of 18 young subjects (age 18-24 years) and 36 elderly subjects (aged 60-85 years) with intraocular lenses (IOLs) were recruited for this study. No subjects had significant eye diseases or media opacities. mfERG was measured in standard conditions using the VERIS system (version 4.1). There were three groups of 18 subjects: (1) 18-25 years, (2) 60-70 years, and (3) 75-85 years. mfERG responses were grouped into central, paracentral, and peripheral regions for analysis. The N1 amplitude, P1 amplitude, N1 latency, and P1 latency of the first-order responses were analysed. RESULTS: Age had no effect on P1 latency, N1 amplitude, and P1 amplitude; however, N1 latencies from central to peripheral regions were significantly longer for group 3 than for group 1. CONCLUSIONS: This study suggests that measured age-related decreases in mfERG responses are due to optical factors (decrease in retinal light levels, scatter) before the age of 70 years, but neural factors significantly affect mfERG topography after the age of 70 years.

Adult↗

PubMed2004

Effects of different degrees of cataract on the multifocal electroretinogram.

AIM: To study the effect of different degrees of nuclear cataract on the multifocal electroretinogram (mfERG). METHODS: mfERGs were recorded from 30 elderly subjects with very mild, mild, or moderate nuclear cataracts using a VERIS System (version 4.1). The subjects were divided into three groups (10 in each group) according to their degree of nuclear cataracts as classified according to the Lens Opacities Classification System III (LOCS III). No subjects had any significant eye disease or degenerative changes except for cataracts. The mfERG responses were grouped into six concentric rings for analysis. Both the N1 and P1 amplitudes and the latencies of N1 and P1 of first-order responses were used for analysis. RESULTS: Amplitudes of N1 and P1 from the central retina (14 degrees) were significantly reduced in patients with mild or moderate cataract when compared with subjects with very mild cataract. However, there was no significant reduction of N1 and P1 amplitudes in the para-central retina (14-40 degrees). There was no difference in the latencies of N1 and P1 in these three groups of subjects. CONCLUSIONS: The mfERG responses from the central retina (central 14 degrees) were affected by the severity of cataract, but responses from the paracentral retina (14-40 degrees) were not affected. This suggests that in interpreting the mfERG in subjects with mild or moderate cataract subjects some care should be taken as reduced amplitudes (N1 and P1) will be expected from the central retina.

Aged↗