Abstract
Purpose: :
The scotopic b-wave response, commonly called the rod ERG, is the standard measure of rod function in clinical ERG testing. The scotopic b-wave response may not be the optimum measure of rod activity. Analysis of high intensity flash a-waves (bright flash ERG) is an additional method of assessing the rod system. This study compares information obtained with rod ERG with that obtained by bright flash ERG.
Methods: :
The bright flash ERG protocol was added to all clinical ERG protocols in our lab. A total of 2396 eyes were recorded. Patient age ranged from 2.4 months to 84.6 years.
Results: :
Bright flash ERG provided additional information on rod system function above that obtained with rod ERG in 25% of eyes recorded, most importantly in subjects with midretinal disease and artificially reduced rod responses. Bright flash ERG also provided a measurable response for longitudinal monitoring in rod dystophies with non-recordable rod ERGs. Results from patients with normal standard ERG results provided information on development of the rod photoreceptor response; bright flash response matures at 3-4 years of age and remains stable throughout adult life.
Conclusions: :
The bright flash protocol is a valuable tool for assessing rod system function in a wide set of retinal diseases and testing situations. Clinical ERG testing would benefit greatly from adding the bright flash protocol to its standard testing conditions.
Keywords: electrophysiology: clinical • retinal development • photoreceptors