Three-dimensional analysis of averaged electroretinograms for the evaluation of rhegmatogenous retinal detachment and related pathological conditions.

Retinal functional imaging in patients with rhegmatogenous retinal detachment and related pathological conditions was undertaken in 62 eyes of 44 cases by means of three-dimensional analysis (X-Y plane and time) of electroretinogram (ERG) topography. The analysis revealed that the area of maximal amplitude in both dominantly photopic and scotopic conditions deviated to the skin area closest to the location of the retinal detachment (hereafter referred to as paradoxical localization). In temporal retinal detachment, for example, the location of the maximal amplitude of the a- and b-waves deviated toward the temporal side on surface topography. Flicker ERG with a stimulus frequency of 30 Hz was especially successful for disclosing the existence and the location of posterior involvement of retinal detachment within the area surrounding the temporal vascular arcades. The mechanisms of paradoxical localization were considered to be changes in the axis of the equivalent dipole in detachment eyes. These abnormalities disappeared after the retina was reattached. Although the buckling procedure and argon laser retinopexy had little effect on the topographical distribution of the a- and b-waves, it was markedly distorted by cryoretinopexy. No remarkable changes in the topographical distribution of the waves were detected in pathological conditions predisposing to rhegmatogenous retinal detachment. This new method for functional imaging of the retina promises to be valuable for objective clinical evaluation of retinal detachment.