Perimetric Mapping of Hyperacuity: Effects of Retinal Laser Scars.
Abstract
The effects of specific graded retinal laser lesions on both vernier acuity and local luminance perimetry were measured by electrophysiological means. Seven Cynomolgus fasciculata received minimal spot laser exposures 6 years previously from a q-switched Nd-YAG laser (1064 nm) at energies up to and including contained subretinal hemorrhages in both the parafovea and the fovea. High contrast vernier acuity targets were presented at high luminance levels to anesthetized primates. Visual evoked potentials were recorded by conventional means. A significant decrease of the pattern response signal/noise, and a relative loss of vernier signal was seen in the lesioned eyes. Animals with the more severe lesions have degraded small pattern responses and no recordable vernier response. Lesser apparent losses produced less effect. Finally, a map of each retina was produced by flickering small patches on the stimulus display and recording the retinal signal. The multifocal (perimetric) electroretinogram was recorded from specialized contact lenses. Relative response losses of no more than 25% were seen at sites corresponding to the more severe foveal lesions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1997
- Accession Number
- ADA328135
Entities
People
- Elmar T. Schmeisser
Organizations
- University of Kentucky