Quantification of spatial vision in the Royal College of Surgeons rat

PURPOSE. To examine how spatial vision deteriorates in the RCS rat over time as a background to experimental studies aimed at limiting photoreceptor degeneration. METHODS. The Visual Water Task was used to quantify the grating acuity of pigmented dystrophic RCS rats as they aged and to compare both grating acuity and contrast sensitivity in nondystrophic RCS rats with those parameters in normal pigmented laboratory rats (Long-Evans). RESULTS. Nondystrophic rats had grating acuities and contrast sensitivity functions that were similar to those obtained from Long-Evans rats. The grating acuity of dystrophic rats deteriorated from 80% of normal at 1 month of age to blindness by 11 months. Acuity declined rapidly to 0.32 cyc/deg over the first 4 months, with a slower decline thereafter. CONCLUSIONS. Robust measures of vision can be achieved in RCS rats using the Visual Water Task, and with this test, no visual dysfunction can be detected in the background strain. The course of functional deterioration in dystrophic rats is highly predictable, allowing the approach to be used to explore the substrates of the deterioration in vision and to monitor the effects of therapeutic retinal interventions on spatial vision.