Quantitative Phenotyping of Chromatic Dysfunction in Best Macular Dystrophy

Abstract

To quantify chromatic dysfunction in Best disease to reassess the classic categorization of macular chromatic damage and to investigate psychophysical and clinical correlations. Methods: Color-contrast discrimination was measured using 2 different psychophysical strategies in agematched control (n = 41) and patient (n = 34) eyes. The first strategy measured performance along 3 main confusion lines (testing cone function), and the second evaluated discrimination ellipses (modified Cambridge Color Test). The main outcome measures were chromatic discrimination variables (confusion line length, ellipse length, angle, and axis ratio) and visual acuity (VA). Results: Significant loss of performance was seen in all color axes in our patients, and it increased monotonically with staging, becoming significant in Fishman stages 2 and 3. The classically assumed preferential type I redgreen deficit was true only for stage 4. Substantial chromatic dysfunction occurred even with relatively preserved VA despite that negative correlations between all test variables and VA reached statistical significance. Partial correlation analysis showed that protan/deutan loss was related to VA independent of tritan loss. Statistically significant positive correlations were also found between lesion size and chromatic dysfunction. Conclusions: Chromatic discrimination is often impaired in Best disease, even when VA is still spared. Our quantitative psychophysical approach shows that the classic categorization as a type I red-green deficit is valid only for disease stage 4.

Independent patterns of damage to retinocortical pathways in multiple sclerosis without a previous episode of optic neuritis

“…We have studied chromatic contrast sensitivity using three parallel, randomly interleaved staircases, corresponding to the simultaneous assessment of the three cone confusion axes, modulated in the CIE 1976 u'v' colour space [12][13][14][15] (modified Cambridge Colour Test, CRS, Rochester, UK). Refractive correction for far vision conditions was worn by participants, and tinted contact or spectacle lenses were replaced by trial lenses in a trial frame, whenever necessary.…”

“…Refractive correction for far vision conditions was worn by participants, and tinted contact or spectacle lenses were replaced by trial lenses in a trial frame, whenever necessary. Thresholds were expressed in confusion vector length for each protan (P), deutan (D) and tritan (T) axes, in CIE 1976 u'v' colour space units (minimum and the maximum excursion 0.002 and 0.11 units, respectively) [13][14][15].…”

Evidence of Widespread Retinal Dysfunction in Patients with Stargardt Disease and Morphologically Unaffected Carrier Relatives

“…means of a anomaloscope (IF-2; Roland Consult, Wiesbaden, Germany; Table 1). Whenever possible, patients (n ϭ 9) were also tested for the three main cone-confusion axes, simultaneously and in an interleaved manner, 22 by modulating chromaticity in CIE 1976 uЈvЈ color space, using a slightly modified version of the Cambridge Color Test (Cambridge Research Systems Ltd.…”

“…We have also quantified L-, M-and S-cone function using a psychophysical method that has already been shown to be useful in understanding structurefunction correlations in other macular dystrophies, namely Best disease. 22 Of importance, we have used the above-mentioned methods to study clinically and genetically characterized asymptomatic relatives, as revealed by normal ophthalmic examination. The goal was to test the possibility of subtle visual impairment in putative carriers, whose carrier state was assessed.…”

Assessing the effects of dynamic luminance contrast noise masking on a color discrimination task

“…Clinical assessment of color vision can be performed by a myriad of tests [1], including several that are run on a computer screen [2][3][4][5]. They determine the type and extent of the color vision impairment in inherited color vision deficiencies [6][7][8], diagnose and monitor clinical conditions in the eye, e.g., retinal conditions [9,10], eye conditions due to diabetes [9], and glaucoma [11], or assess the benefits of gene therapies [12], among others [13][14][15].…”