The effect of oral isotretinoin on retinal activity using the three different electrophysiological tests, ERG, EOG, and VEP to determine which test is more affected by this drug and should be used as a tool for following patients taking this drug.

25pations with acne using oral Isotretinoin (0.5 -1 mg /kg/day) at least for 4 months without any ocular disease or systemic disease affecting the retina, age less than 50 years. VEP, EOG and ERG were recorded using Mangoni instruments. Checker board pattern reversal for VEP, Flash for ERG and finally light adaptation to dark adaptation ERG and light adaptation to dark adaptation ratio for Arden index (EOG).

A Comparison made with the normal values through statistical tests. A significant increase was seen in b wave latency in ERG test (p=0.05). ERG amplitude, P-100 latency and amplitudes were in the normal range. Only one patient had abnormal Arden index for EOG test. Only two patients had increased VEP latencies.

Isotretinoin may adversely affect the inner retinal cells such as bipolar and amacrine, and physicians could use ERG b wave latency test as the best for following patients taking Isotretinoin medication and detecting the subtle subclinical retinal changes.