Abstract
Purpose: :
Knowing that color vision and object perception is processed preferential the input of parvo pathways and space perception is processed preferentially by the input of magno pathways, the aim of this study was to investigate if the deficit in color vision affects visual perception of space and object in patients with Relapsing-Remitting multiple sclerosis (MS).
Methods: :
We studied 34 patients with multiple sclerosis divided into two groups according to their color vision thresholds measured with the Trivector procedure of the Cambridge Colour Test. MS group (n=15) had normal color vision or an increased threshold along only one color confusion axis (mean age 31.9± 9.8 yo). MSCV group (n=17) had increased thresholds on at least two out of the three axes (mean age 41.4 ± 10.5 yo). All patients had visual acuity of 0 logMAR or better. Results were compared to those of healthy controls (n=21) matched according to gender, age (mean age 36.5± 10.8 yo) and educational level. Subjects were evaluated with the "Visual Object and Space Perception Battery (VOSP)", which included four subtests for object perception (Incomplete Letters, Silhouettes, Object Decision, and Progressive Silhouettes) and four for space perception (Dot Counting, Position Discrimination, Number Location, and Cube Analysis). Statistical analyses were performed with commercial software (IBM - SPSS Statistic), using a General Linear Model (GLM) and the Sidak post hoc test.
Results: :
Data analysis showed significant differences on subtests for space perception (Group MS x MSCV p=0.010 and MSCV x Control p=0.001) and object perception (Group MS x MSCV p<=0.001, MSCV x Control p<=0.001 and MS x Control p<=0.001). These results did not correlate with age, sex and educational level.
Conclusions: :
MS patients with color vision loss had both deficits in spatial perception and object perception subtests. On the other hand, MS patients with normal color vision had impairment only in object perception. In this disease, when there is already a deficit in color vision, perception of space and object is also affected. Future studies will investigate if the losses are more related to perception or to memory impairment.
Keywords: color vision • visual impairment: neuro-ophthalmological disease