Purpose: To test the hypothesis that ocular pigment in patients with oculodermal melanocytosis decreases myopia severity.Methods: Refractive and biometric parameters were measured and compared between pigmented eyes and non-pigmented contralateral eyes in oculodermal melanocytosis patients that underwent surgical ocular pigmentation removal. To assess pigmentation, the pigmentation score was measured in each quadrant of the sclera and added together for a cumulative score. For subgroup analyses, patients were categorized into three groups according to the severity of myopia in the non-pigmented eye.Results: Fifty-five patients (110 eyes) were included. Spherical power and spherical equivalent were significantly less myopic in pigmented eyes relative to contralateral non-pigmented eyes. The spherical powers of non-pigmented eyes were positively correlated with the difference in spherical power between contralateral eyes (r = 0.697, p < .001). The pigmentation scores of pigmented eyes were positively correlated with the ratio of myopia inhibition (r = 0.373, p = .005). In subgroup analyses, pigmented eyes exhibited significantly less myopic spherical powers and spherical equivalents than non-pigmented contralateral eyes in the moderate and high myopia groups. Pigmented eyes exhibited significantly shorter axial length than non-pigmented contralateral eyes in the high myopia group only.Conclusions: In patients with oculodermal melanocytosis, pigmented eyes exhibited less severe myopia relative to non-pigmented contralateral eyes. This suggested that ocular pigmentation inhibited myopic changes, potentially by blocking UV transmission. This study will be helpful in elucidating the mechanisms of myopic progression.
Keywords: Nevus of Ota; melanins; myopia; ocular pigments.