Colour contrast sensitivity in ocular hypertension. A five‐year prospective study

Abstract

ABSTRACT.Purpose: To evaluate a peripheral colour contrast sensitivity test as a tool for early diagnosis of glaucoma in a five-year prospective study. Patients and methods: Peripheral colour contrast sensitivity was measured with a computer graphics system developed by Arden et al. The test colours were varied along the protan, deutan and tritan colour confusion axes on a scale from 0 to 100 percentage units. Fifty-five ocular hypertensive (OH) patients examined with the colour contrast test, stereoscopic photography of the optic discs, and measurements of visual fields (Humphrey 24-2 glaucoma hemifield test (GHT)) in 1994, were re-examined after five years. Results: Ten patients were 'outside normal limits' in the GHT at follow-up. This group of 10 patients did not differ in colour contrast thresholds at the test in 1994 from the 45 who were still 'normal' (or 'borderline') at follow-up. Neither were there proportionally more patients with GHT 'outside normal values' for the patients with high colour contrast thresholds (Ͼ 30% units) in 1994 regarding any of the three colour axes. As judged from patient files, 27 patients had developed glaucoma during follow-up. Although there were differences between these 27 glaucoma patients and the remaining OH group at the colour contrast test in 1994, these differences did not reach statistical significance for any of the colour axes (largest difference in the tritan axis: 6.2% units, P Ω 0.0745). At follow-up, however, there was a significant difference in colour contrast for the protan axis between the clinical glaucoma group and the OH group (6.7% units, P Ω 0.0105). Conclusion: The method used for colour contrast measurement did not reveal glaucomatous changes before conventional perimetry (Humphrey 24-2, GHT). Neither did it predict the patients who, in our clinic, subsequently developed glaucoma during a five-year period. A change over time in colour contrast in the protan axis for an OH patient may, however, indicate glaucoma development.

Simultaneous Comparison of Relative Damage to Chromatic Pathways in Ocular Hypertension and Glaucoma: Correlation with Clinical Measures

“…Furthermore, these measures proved to be significantly good predictors of perimetric damage (along with measures of ellipse length), which is in agreement with a recent finding that development of glaucoma may actually be best predicted by a change in the length of the protan discrimination axis. 41 We may indeed be facing the problem that a parameter that causes the severest damage does not imply that it is the most useful measure, because no significant correlation was found between tritan axis length and perimetric damage under the conditions of our measurements. Despite the prominent tritan loss, this measure correlated the least with progression of field loss once glaucoma was established.…”

“…Some studies including patients with ocular hypertension have emphasized the level of dysfunction at the visual periphery for the tritan axis 17,28 but their results have not always been concordant. 35,41 Substantial damage has been extensively reported for the magnocellular system [45][46][47][48] (for a review see Shabana et al 48 ), partly from indirect evidence that large fibers are preferentially affected early on in this disease. 49 -51 These findings have formed the basis for the so-called preferential damage hypothesis.…”

Reduced Mesopic and Photopic Foveal Contrast Sensitivity in Glaucoma

“…6,[30][31][32] Foveal involvement early in glaucoma has been a controversial issue. 33,34 The maintenance of good visual acuity until late in the disease and the absence of characteristic central visual field defects lead to the belief that the fovea remains unaffected in the early stages of the disease. However, the density of ganglion cells is 10-fold greater at the fovea than the density at 25°eccentricity and 100-fold greater than at the farther periphery, 19 an effect that enables substantial redundancy at the fovea 27 to overcome the early loss in the glaucomatous process, sparing normal foveal function.…”

Colour and inclusivity: a visual communication design project with older people

“…The loss of chromatic sensitivity in the short wavelength part of the spectrum in glaucoma was confirmed by others. Short wavelength automated perimetry (SWAP) has been shown to detect glaucoma damage earlier than conventional white-on-white perimetry and also to be more sensitive to progression of visual field loss, and to progression of glaucomatous disc cupping [10]. Other eye diseases, such as low-grade type 2 diabetic retinopathy [9] and moderate cataract [11] have been shown to affect peripheral colour contrast.…”