A method for producing foveal retinal exposures in an awake, task-oriented, rhesus monkey

Visual Functional Changes Associated With Low-level Light Effects

“…In experiments designed to measure the immediate effects of acuity loss from foveal exposure in awake task-oriented rhesus (Robbins et al 1973(Robbins et al , 1980Robbins and Zwick 1980;Graham et al 1971), thresholds for permanent change were far more consistent with histological criteria than for exposures made under anesthesia where several days elapsed before acuity could be remeasured in exposed eyes. At transition levels of exposure from temporary to permanent visual acuity loss, more than one exposure was required to produce a permanent loss in visual acuity.…”

Permanent Visual Change Associated with Punctate Foveal Lesions

“…Several recent experiments (4,14) have suggested that acute exposures can have non-thermal components, especially at energy levels determined for the transition zone from temporary to permanent visual function change. Tt is possible that such foveal retinal damage mechanisms could not be elucidatel in studies similar to those mentioned above, where tne entire foveal reaion has undergone gross damage.…”

“…Four rhesus monkeys (Macaca mulatta) were trained on a Landolt ring visual acuity task (12,14,15) in which exposure to a laser flash could be administered during task performance (4,14). Training required 6 to 9 months for each animal to successfully discriminate Landolt rings from gapless rings and several additional months for stable threshold acuity measurements in each animal.…”

“…Contrast sensitivity for Landolt ring test stimuli was determined by an up-and-down visual tracking procedure (4,12,14,15), allowing, V rapid determination of threshold. Animals were trained to yield highly stable baselines with minimal variation across sessions.…”

Functional Assessment of Laser Irradiation

“…During the course of the last several years we have developed a method for producing foveal exposures in an awake, task-oriented animal (11,12). Associated with this procedure has been the development of a rapid method to measure rhesus visual acuity immediately before and after laser exposure.…”