The optic nerve and peripapillary vasculature in albinism
New Frontiers in Ophthalmology
Albinism, an inherited disorder resulting in reduced ocular melanin, is usually associated with reduced best-corrected visual acuity, nystagmus, foveal hypoplasia, and iris transillumination. However, a spectrum of findings has been reported, with foveal hypoplasia, nystagmus, and misrouting of the retinostriate fibers having been purported to cause reduced visual acuity. The purpose of this case-controlled study is to describe the optic nerve anatomy and peripapillary retinal vasculature in
... l vasculature in albinism and to determine if there are changes related to visual acuity. We evaluated digital fundus photographs using computer analysis software in 34 patients with albinism and 51 controls. Our data indicate that the optic disc diameter and optic nerve area are significantly smaller in patients with albinism than controls (p <0.001; p=0.0008, respectively). Significantly more patients with albinism also had a double ring sign, situs inversus, and a nasally-directed artery (p ≤ 0.0148). There were no significant differences between groups for optic nerve color, vessel branching pattern, cilioretinal artery, or number of vessels crossing the optic nerve margin. Correlation of best-corrected visual acuity to disc diameter and optic nerve area was poor (r=0.0542 r=0.1527, respectively). In this study, patients with albinism had mild optic nerve hypoplasia when compared to controls. Reduced best-corrected visual acuity is not explained by the optic nerve findings. Further studies are required to elucidate the causes of reduced best-corrected visual acuity in albinism.