Multifocal electroretinography in the study of focal and diffuse damage to the rabbit retina

Abstract

To evaluate the possibility of using the system "Neuro-ERG" (with a module for multifocal ERG) in the study of focal and diffuse pathology in laboratory animals (rabbits). Focal retinal damage was modelled in 5 eyes of 5 rabbits by singular laser pulses (532 nm, 100 ms, power 30, 60, 100, 150 and 200 mW) and diffuse retinal damage was modelled in 5 eyes of 5 rabbits by exposure to polychromatic light for 14 days (9500 lm, 6400 K, 230 mW/cm2, 8 h/day). The pair of eyes and areas of intact retina in the eyes with focal retinal damage were used for control. Multifocal electroretinography (mfERG) was recorded using the «Neuro-ERG» system (Neurosoft, Russia) before exposure, after 1 hour (in focal damage model), and 1, 7 and 14 days after exposure. In addition, three-time recording of mfERG was made before and after the experiments. Analysis included the amplitude and time characteristics of mfERG components, as well as the level of reproducibility of mfERG at each recording. In the modeling of focal damage of the rabbit retina, significant changes in mfERG (pattern stimulus consisted of 61 hexagons) were detected when the retinal damage area was more than 170 µm in diameter or more than 35% of the hexagon area in the pattern-stimulus. A significant moderate inverse correlation (0.52<r<0.71, p<0.01) was found between the damage area and the amplitude P1 and density of the bioelectric response of the P1 component. When modeling diffuse damage, significant changes in mfERG (an increase of implict-time of P1 and a decrease in the amplitude and density of the bioelectric response of the P1 component) were detected on the 7th day after the beginning of exposure. Variability of mfERG recording on each registration averaged 5%. Multifocal ERG registration systems, including «Neuro-ERG» (Neurosoft, Russia), can be used in experimental studies of vitreoretinal pathology with rabbits as biological objects.