Flicker electroretinograms of eyes with cataract recorded with RETeval system before and after mydriasis

The aim of this study is to determine the effect of pupil size of eyes with cataracts on the flicker electroretinograms (ERGs) elicited and recorded with the RETeval system.

Forty-one eyes of 41 patients (mean age, 76.5±7.3 years) that had grade 2 nuclear or cortical cataract without any other abnormalities were studied. Flicker ERGs were recorded before and after mydriatic drops instillation. The ERGs were elicited by the white light delivered at the frequency of 28.3 Hz and intensities of 2, 8, and 32 Td-s. The amplitudes and the implicit times of the flicker ERGs before and after mydriasis were compared.

There were no significant differences between the amplitudes before and after mydriasis (P=0.35, 2 Td-s; P=0.31, 8 Td-s; P=0.50, 32 Td-s). There were also no significant differences between the implicit times before and after mydriasis (P=0.86, 2 Td-s; P=0.98, 8 Td-s; P=0.95, 32 Td-s). The mean amplitudes and implicit times of the nuclear and cortical cataracts groups before the mydriasis were also not significantly different from those after mydriasis for all stimulus intensities.

The lack of significant differences in the amplitudes and the implicit times of the flicker ERG of cataractous eyes before and after mydriasis indicated that the RETeval flicker ERGs in cataractous eyes is less affected by the pupil diameter. With our earlier study, it was assumed that the effect of cataracts on the RETeval flicker ERGs was due to the opacity of the crystalline lens, and the influence of the cataract would not be reduced or increased by mydriasis.