The Effect of Threshold Macular Lesions and Sub-Threshold Macular Exposures on Visual Acuity in the Rhesus Monkey

摘要

The purpose of this research program was to evaluate retinal threshold burns and subthreshold exposures of the mammalian macula in terms of visual acuity. Rhesus monkeys (Macaca Mulatta) were trained by a reward system to respond to the automated presentation of Landolt rings, according to the method of Graham, McVean, and Farrer. After appropriate training, these animals were exposed to threshold and sub-threshold levels of retinal energy density ranging from 3.2 to 10.7 J/sq cm, exposure time approximately 135 ms, spectral quality approximately that of color temperature 60000K with wavelengths above 900 nm removed, and image sizes on the retina of about 1 mm diameter, covering a major portion of the monkey macular area. Results, in terms of visual acuity decrement (monocular), indicated that energy densities on the retina below 5 J/sq cm, were not statistically significant, whereas energy densities greater than 5 J/sq cm produced losses in visual acuity (monocular) which were significant. These results indicate that at levels of energy density on the retina which are 80 to 50 percent below the threshold burn level, no loss in visual acuity can be detected in the Phesus monkey by the Landolt ring testing system adopted for this investigation. (Author)