Abstract
Abstract: :
Purpose:Arden has suggested that the recently–described non–photic alcohol–induced EOG (Alc–EOG) can detect early ARMD. We have evaluated the specificity, reliability and applicability of this test, as well as the standard EOG, in normals and disease. METHODS: Normal subjects (29), and patients with ARMD (11) and central serous chorioretinopathy (CSC, 11) were studied. For the Alc–EOG, an oral dose of alcohol (160 mg/kg) was followed by EOG recording. Blood alcohol concentrations were monitored by a breath analyzer. After 90 min, an ISCEV Standard light–induced EOG (Li–EOG) was recorded. Results: The Alc–EOG peak–to–baseline ratio showed great variability among normal subjects, with values ranging between 1.0 and 2.0 and showing no relationship to either blood alcohol levels (near the time of the peak) or the Li–EOG. Li–EOG Arden ratios also showed greater inter–individual variability. Patients with ARMD and CSC showed a scatter of data that overlapped the normal range, and had similar mean values. There were no clear differences between wet ARMD eyes and dry ARMD eyes, or between CSC eyes and fellow eyes. Conclusions:The Alc–EOG eliminates the role of light in the EOG response, but in our experience the test gave results that were too variable for the monitoring of individual subjects in clinical practice. In contrast to Arden's data on ARMD, we found no differences between ARMD and CSC patients and normals (even as group means). Some of the intersubject variability may reflect disparate alcohol absorption times with oral administration. The standard Li–EOG also showed enough variability to question its diagnostic value, except when severely depressed in Best disease. The quest for an effective clinical test of RPE function remains unfulfilled.
Keywords: electrophysiology: clinical • age-related macular degeneration • retinal pigment epithelium