Department of Ophthalmology, University of Sydney, Sydney Eye Hospital, Woolloomooloo, Australia.
The corneas of 50 normal subjects were examined before and after electroretinography performed with gold foil electrodes. Examination included slit-lamp biomicroscopy and staining with sodium fluorescein. All corneas were normal on examination prior to electroretinography. Three types of transient corneal changes were observed--punctate epithelial keratitis, corneal erosions, and stromal thinning. Each cornea was assigned a numerical damage score based on a simple scoring system. Thirty one subjects (62%) had some degree of corneal change, and in three cases (6%) follow-up was required. Multiple regression analysis was performed to discover any risk factors. Both age of the subject and the use of local anaesthetic were strongly associated with corneal changes.