Detection of ophthalmic impairments indirectly with electronystagmography

The objective was to develop, from a pool of clinical electronystagmography (ENG) data, normal lower limits for the corneo-retinal potential (CRP). The CRP evaluated in the present study was derived as a byproduct of eye movement calibration with a computerized ENG system. The data set was collected from a cohort of patients without history of ophthalmic disease. This normative study was designed to develop upper and lower limits for the CRP recorded indirectly from ENG testing. Subjects were 107 consecutive patients (41 males, mean age 57 years). Subject age did not, but gender did affect significant changes in the CRP. Specifically women showed larger CRP values than men. Case studies are presented that support the contention that the dark-adapted CRP may be helpful in the identification of patients with ophthalmic diseases known to affect the CRP and, thus, augment information normally obtained in the course of the ENG examination.