THE INFLUENCE OF INDUCED FORWARD LIGHT SCATTER ON THE NORMAL BLUE-ON-YELLOW PERIMETRIC PROFILE

The study investigated the effects of induced forward light scatter on the normal blue-on-yellow perimetric profile. Light scatter was induc ed using 0.00%, 0.08% and 0.16% suspensions of 500-nm-diameter Polysty rene microspheres contained in optical cells. White-on-white, yellow-o n-yellow and blue-on-yellow perimetry was performed using a modified H umphrey Field Analyser 640. Fifteen subjects performed perimetry with each of the scatter suspensions placed before the eye and in the cell- free situation. The degree of induced scatter for each cell was quanti fied using the direct compensation technique of van den Berg at small, medium and large angles of scatter. Straylight increased and perimetr ic sensitivity decreased with increase in scatter concentration. Forwa rd light scatter caused general reduction in sensitivity for all stimu li, particularly for the blue-on-yellow stimulus. This finding may hav e implications for the interpretation of the glaucomatous visual field in the presence of forward light scatter.