Contrast Sensivity After Foto-flicker Stress and Blue-on-yellow Perimetry in Detection of Early Glaucoma

Abstract

Abstract: : Purpose: Early knowledge on the progression of glaucomatous optic neuropathy may improve the ability to fight the disease. It has been suggested that clinically detectable changes of the blue-on- yellow visual field may precede standard white-on-white visual field defects in the progression of glaucoma. The aim of our study was to investigate the relationship between recovery of contrast sensitivity after photo-flicker stress and blue-on-yellow (B/Y) perimetry in detection of early glaucoma. Methods: 120 outpatients with glaucoma suspect (group I) whose visual acuity was 20/40 (logMAR 0.3) or better were involved in this study. An equal number of sex and age matched subjects were used for control (group II). All these patients did not show white-on-white visual field defects. B-Y visual field (program Central 30-2) was obtained with a Humphrey perimeter. B-Y perimeter results were adjusted for the patient's age. The mean deviation (MD) score from the Humphrey visuald field was used to quantify the visual field defect. Contrast sensitivity was determined for stationary 0.99 Hz phase-alternating gratings at one frequency (0.71 c/deg). Three contrast thresholds were performed (88.80%, 50.00%, 25.00%), before and after monocular exposure to 30 sec of photo-flicker stress. Amplitude and latency were examined. Results: Group I and group II differed significantly in peak times and amplitudes of the low contrast stimulus. A decrease in the contrast sensitivity correlates with increased visual field loss (MD) more frequent among patients with glaucoma suspect. Conclusion: The authors recommend examination of the contrast sensitivity after photo-flicker stress and B-Y perimetry as a supplementary methods for screening and observation of ocular hypertension and suspect glaucoma.

Keywords: electrophysiology: clinical • contrast sensitivity • visual fields