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Abstract #6360 Published in IGR 3-2
Electroretinographic abnormalities in a rat glaucoma model with chronic elevated intraocular pressure
Bayer AU; Danias J; Brodie S; Maag KP; Chen B; Shen F; Podos SM; Mittag TWExperimental Eye Research 2001; 72: 667-677
The purpose of this study was to determine the ability of electroretinographic (ERG) measurements to document progression of the retinopathy in a rat glaucoma model. Thirty-four rats with a chronic intraocular pressure (IOP) elevation induced in one eye by cautery of three episcleral/extraorbital veins were studied in four separate groups. ERGs were recorded sequentially in Group A rats (n = 12) at baseline, and after approximately 20, 40, and 60 days of high IOP, and in three additional groups of rats (n = 6 or 10 per group) after approximately 58, 30, and 175 days of high IOP, respectively. Scotopic ERG parameters recorded simultaneously from both eyes in Group A rats were: a- and b-wave amplitudes, implicit times, oscillatory potential amplitude (OPs) determined at three different light-flash intensities, and the light-adapted (photopic) ERG b-wave amplitude. In the other groups of rats, only scotopic ERG a-wave, b-wave, and OP amplitudes were measured. In Group A rats that were followed sequentially, all the ERG parameters recorded with attenuated stimuli showed significant time-dependent changes in glaucomatous eyes relative to their contralateral normal eyes, with OPs showing the earliest significant difference after only three weeks of high IOP. When different groups of unilateral glaucomatous rats were compared beyond eight weeks of elevated IOP, only the OPs showed a continued decrease with time and good discrimination between glaucoma and normal eyes. Over a 25-week period of high IOP, the scotopic OPs measured with attenuated light stimuli declined at the rate of approximately 1.5% per week, and provided the best ERG measure to monitor progression of retinal pathophysiology in the vein-occlusion rat glaucoma model.
Dr A.U. Bayer, Department of Ophthalmology, Mount Sinai School of Medicine of New York University, New York, NY, USA
Classification:
5 Experimental glaucoma; animal models
6.7 Electro-ophthalmodiagnosis (Part of: 6 Clinical examination methods)