Quantitative evaluation of photopic ERG waveforms.

Quantitative, computer-based ways of representing photopic ERG waveforms are investigated and related to over-all retinal condition in a group of normal subjects and a group of patients with diagnosed retinitis pigmentosa. Sinusoidal stimulation and a Fourier series response representation have been selected. This combination provides a few parameters which facilitate waveform comparison, and it naturally lends itself to generalization if more detailed features of ERG recordings are to be included. On the basis of this type of waveform characterization, the over-all photopic retinal condition of any individual eye can be represented by a single number or by its location in various cluster diagrams and its distance from the normal cluster. As exemplified by the results herein described, such an automated approach can be particularly useful in screening large populations for retinal degenerations or in quantitatively following the progression of retinal degeneration over long periods of time.