A note on senile cataracts and the electroretinogram

Abstract

JEAN NORDMANN who is being honored today has left an imprint on many fields of ophthalmology. But the field with which his name is most closely associated is that of the biology of the crystalline lens. It is for this reason that we have chosen to present a note on the influence of senile cataracts on the responses obtained in human ERG*.It is generally stated in the literature that clouding of the refractive media of the eye (including senile cataracts) has of itself no effect on the electric responses of the retina and that there are no significant differences in the ERG obtained pre-and post-operatively (KARPE & VAINIO-MATTILA (1951) and others). There is no reason why it should be otherwise. Provided the light stimulus can reach the retina, a response commensurate to the retinal illumination should be achieved, as long as the retina itself is in a normally functioning state. Yet the question remains how much light does reach the retina in eyes with cataractouslenses. Clearly, a certain amount of light must be absorbed by such lenses and mature, brunescent lenses undoubtedly absorb a considerable amount. One would, therefore, expect in such eyes a larger ERG post-operatively than preoperatively. This is, indeed, the case; and KARPE • VAINIO-MATTILA, who were mainly interested in ERG as a functional test for cataractous eyes, state accordingly that it is in some instances necessary to use a more intense light stimulus to obtain a 'normal' ERG.

Comparing the Multifocal Electroretinogram Topography before and after Cataract Surgery

“…This suggests to us that the effects of a cataract are not only to decrease the contrast and luminance of the retinal image but also act as a diffuser to cause light scattering and produces the "Ganzfeld effect." 39 In addition, it also reminds us that light scattering (media opacity) like poor fixation could distort the stimulus-retina correspondence, which is the essence of multifocal technique. Because the distortion of this stimulus-retina correspondence can reduce the response in the center more than the periphery, 34,40,41 it further explains why cataract mainly affect the central retinal responses not the peripheral retinal responses.…”

The Success of Cataract Surgery and the Preoperative Measurement of Retinal Function by Electrophysiological Techniques

“…Electrophysiology technologies have been used to examine retinal function prior to cataract surgery. Visual electrophysiology techniques such as pattern visual evoked potential (PVEP) and flash electroretinogram (ERG) are used in appraising the necessity of cataract surgery and postoperative visual function [ 4 , 5 ]. PVEP is used to measure the functional integrity of the visual pathways from retina via the optic nerves to the visual cortex.…”

Single flash electroretinograms of mature cataractous and fellow eyes

“…It is generally stated that opacities of the ocular media, including senile cataract, have little effect on the electrical responses of the retina. 1 , 2 Single flash electroretinogram (ERG) has been widely used, as a commercially available technology, to examine retinal function prior to cataract surgery, especially when the opacity is so severe that visual acuity (VA) of the patient is extremely poor and fundus condition is not visible. In a previous study with 22 patients with mature cataract, it was observed that single flash ERG values decreased depending on the degree of cataract opacity, even though the difference was not significant 3 and Uji showed that the amplitude of ERG b-wave was significantly increased after cataract surgery in comparison to the preoperative result.…”