Peripheral colour contrast thresholds in ocular hypertension and glaucoma

Abstract

ABSTRACT.Purpose: To evaluate a new test for peripheral colour contrast sensitivity as a tool for early diagnosis of glaucoma.Patients andMethodc Peripheral colour contrast sensitivity was measured by a computer and colour monitor system developed by Arden and co-workers. The monitor displays an annulus subtending 25" at the retina. During the test, 45" of the annulus is removed in one of four quadrants. The patient is asked to identify this quadrant, first at suprathreshold levels and then as the colour contrast between the annulus and the background is vaned in order to establish the threshold for identification. The tested colours were varied along the protan, deutan and tritan colour confusion axes, respectively. Thirty-three normal subjects, 22 glaucoma patients and 69 ocular hypertensive patients were examined. The ocular hypertensive patients were divided into a low risk group, a medium risk group and a high risk group. Results: The colour contrast thresholds for the glaucoma group and the high risk ocular hypertensive group were significantly (p < 0.001) higher for all three colour axes compared with the normal group. There were also significant (p < 0.05-0.001) differences for all axes between the glaucoma group on the one hand and the ocular hypertensive low risk group on the other hand. There were, however, overlaps in colour contrast thresholds between all groups. Conclusion: Although there is a large and statistically significant difference in average colour contrast thresholds between normals and glaucoma patients, it was difficult to find an appropriate cut-off point to separate the two groups. Further studies must clarify the influence of early stages of common diseases such as cataract, diabetes and age-related maculopathy on colour contrast sensitivity.

Evaluation of Acquired Color Vision Deficiency in Glaucoma Using the Rabin Cone Contrast Test

“…7 Recent investigations of chromatic discrimination using computer-generated color tests have shown that color contrast thresholds are elevated in patients with glaucoma. [8][9][10] In these tests, the subject is asked to report the presence of a color target such as a spot, bar, or grating on a background of a different color. Regan et al 11 designed a sophisticated computerized color vision test known as the Cambridge Colour Test.…”