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Although visual function and visual performance have both been investigated, the relationship between these measures is largely unexplored. In this study, we have evaluated the receptor input for visual pursuit motor tracking performance using the rhesus monkey as an animal model for the human visual system. Spectral sensitivity functions derived from rhesus spectral intensity tracking performance functions emphasize the role of photopic retinal mechanisms for high fidelity tracking performance criteria. Spectral sensitivity functions under these conditions appear photopic in shape and reflect central retinal long and intermediate cone systems. Scotopic intrusion may occur as performance decreases with lower fidelity performance criteria. Species differences previously reported between rhesus and human long wavelength foveal retinal mechanisms may be reflected in visual performance criteria as well.

In this investigation we examined the effect of near-infrared intense macular laser exposure on the non-human primate focal ERG spectral sensitivity function. Five cynomologous monkeys were exposed to two parafoveal Q-switched Neodymium (1064 nm) lager pulses at approximately 4 millijoules Total Interocular Energy (TIE). Exposures varied in degree of overlap through the superior portion of the fovea. Focal ERG spectral sensitivity was measured in the foveal region using a synchronous detection technique. Alteration in the long wavelength region of the focal ERG spectral sensitivity function was observed in all animals. This alteration could indicate a dominant presence of the long wavelength primate cone system. The dominance may be the result of neural disinhibitory effects of damaged photoreceptors and the complications of retinal fibrosis on normal receptor activity and orientation as well as normal retinal receptor reparative functions. Spectral sensitivity, fovea, retinal fibrosis, reparative functions, photoreceptors.

We describe two cases of parafoveal Q-switched laser retinal injuries which illustrate the variability of the processes set in motion by retinal laser injuries. The first case demonstrates that parafoveal lesions may cause an immediate degradation in visual functions which may recover spontaneously to almost normal levels. In the second, multiple parafoveal exposure sites produced central retinal scars at the parafoveal lesion sites and resulted in retinal traction over an extensive region of the retina with local retinal hole formation at the edge of the central scar. A central arucate absolute scotoma appeared shortly after exposure. The central scotoma, as well as visual acuity, stationary and dynamic contrast sensitivity functions were permanently altered. No treatment presently exists to alleviate or minimize the effects of this retinal scarring process.