Abstract
Abstract: :
Purpose: The rabbit retina differs from the human one in several ways. It is rod-dominated and does not contain a macular region. Instead, there is a horizontal streak below the optic nerve, the visual streak, where the highest density of cones is found. The purpose of the present study was to determine if standardized full-field ERG and multifocal ERG recordings could be obtained from the rod-dominated rabbit retina. Methods: Six animals aged 3 months, and 11 animals between 15 and 27 months were investigated with full-field electroretinogram including the bipolar Burian-Allen contact lens and Ganzfeld dome. Twenty different rabbits were investigated with multifocal ERG, using a stimulus consisting of 103 unscaled hexagons. A Burian-Allen bipolar contact lens with built-in infrared emitters was used to visualize the fundus so that the stimulation area could be controlled during the recordings, using an infrared fundus camera. Results: Full-field ERG: All animals displayed well detectable and reproducible separate cone and rod responses on stimulation with dim blue light, white light, and 30 Hz flicker under both light and darkadapted conditions. The b-wave amplitude was significantly smaller (p< 0.01) in the 3-month animals than in the older ones, but no significant difference was found when comparing the b-wave implicit time. Multifocal ERG: The recordings were clear and reproducible. Maximum amplitudes were obtained in an area corresponding to the visual streak, and low amplitudes were recorded in an area corresponding to the optic nerve head and medullary rays, in good correspondance with the distribution of cones in the rabbit retina. Conclusions: Full-field ERG testing using the ISCEV standard, originally developed for the human eye, can be used in the rabbit with reproducible results. The mERG is a tool well suited for investigating the rabbit retina, where the stimulated area can be controlled using an infrared detection system. The amplitudes reflect retinal function and are well correlated to the cone density.
Keywords: electroretinography: non-clinical • animal model • retina