Stereopsis in patients with albinism: Clinical correlates

Purpose: A hallmark of albinism is excessive decussation of retinostriate p rojections at the optic chiasm. This mis projection might lead to abnormali ties; in the retinal correspondence and may account for the usual absence o f stereovision. We report on 2 groups of patients with albinism who have ei ther fine or gross stereopsis and compare the clinical findings of these gr oups to Other patients with albinism with similar visual acuities but no st ereopsis. Methods: A retrospective chart review of patients with albinism w as used to segregate those with a letter visual acuity of 20/100 or better in one eye, assessment of stereopsis, and strabismus less than or equal to 10 PD. Forty-five patients were identified. Albinism type, best-corrected v isual acuity, motility, Titmus vectograph stereoacuity, iris and macula tra nsparency grades, and the presence or absence of both melanin and an annula r reflex in the macula were tabulated. A comparison of the clinical charact eristics of the groups with a nd without stereopsis was made. Results:Those albino subjects who demonstrated stereopsis had better visual acuity, less iris transillumination, more frequent presence of melanin in the macula, l ess nystagmus, and less marked foveal hypoplasia than the albino subjects w ithout stereopsis. No nystagmus was clinically detected in 5 patients with fine stereopsis. All these differences were statistically significant. Macu lar transparency grade was not significantly different between the groups. Conclusions: Patients with albinism who demonstrate stereopsis tend to have better visual acuity, more iris pigment, and more melanin pigment in the m acula than their counterparts without stereopsis.