Alcohol- and light-induced electro-oculographic responses: variability and clinical utility

The alcohol-induced electro-oculographic (EOG) response has been proposed by Arden as an indicator of retinal pigment epithelial (RPE) integrity. We have evaluated the consistency of the alcohol-EOG with respect to clinical applicability and compared this response to the ISCEV-standard EOG. We recorded, in a group of normal subjects (n=29, 14 men with mean age 42+/-11 years and 15 women with mean age 36+/-13 years), the alcohol response to a single oral dose of ethanol at 160 mg/kg (as 40 proof vodka, drunk in 15 s after 12 h of fasting), followed by an ISCEV-standard EOG 90 min after alcohol administration. Blood alcohol levels were monitored at regular intervals with a breath analyzer. We found a wide range of amplitudes in both light and alcohol responses among participants, from minimal to large values. Subjects had a wide range of blood alcohol concentrations from 0.02 to 0.10%; near the time of the response peak, but there was no relationship between alcohol levels and peak/baseline ratios. In addition, there was no relationship between alcohol peak/baseline ratio and the Arden ratio. Neither the alcohol nor the light response parameters showed any relationship with age or gender. Some of the inter-individual variability in the EOG response to alcohol may reflect variable absorption of oral alcohol. The alcohol-induced EOG has too broad a range of responses to be useful clinically for the one-time evaluation of individual patients. We have similar concerns regarding clinical applications of the standard light-induced EOG.