Electrophysiologic assessment of photoreceptor function in patients with primary open-angle glaucoma

Electroretinograms to high-intensity flashes were obtained to determine the extent of rod and cone photoreceptor and postreceptor dysfunction in patients with primary open-angle glaucoma.

Full-field flash electroretinograms were obtained using brief high-intensity flashes. Dark-adapted (rod-dominated) and light-adapted (cone-dominated) electroretinogram responses were recorded to a "white" light as a function of flash intensity. The a-wave data were fitted with a model based on photopigment transduction to obtain values for the parameters of log Rmax (the maximum response) and log S (sensitivity). Oscillatory potentials were measured to the cone-dominated high-intensity flashes. Standard clinical 30 Hz flicker electroretinogram responses were recorded using a Grass photostimulator.

Analysis of rod and cone a-wave data showed that log Rmax and log S values were within the normal range in nearly all of the patients. For some patients, oscillatory potentials were delayed beyond the normal range.

Our results provide little evidence for widespread photoreceptor abnormalities in primary open-angle glaucoma.