Paired samples T-test.

Purpose
To determine if visual maturation continues beyond the first decade of life in children with albinism and whether this is related to albinism type, presence of nystagmus, eye muscle surgery or refractive errors.
Design
Case series based on retrospective study of children with confirmed genetic diagnosis of albinism.
Methods
Clinical data were obtained from medical files of children examined during school years, including albinism type, visual acuity, eye muscle surgery, nystagmus, and others on different visits (Visit 1: ages 7–9; Visit 2: ages: 10–12; Visit 3: ages 13–16; Visit 4: ages >16).
Results
Seventy-five children with albinism were included in the study. Patients were divided into different groups according to the albinism type including OCA1A: 17; OCA1B: 28; OCA2: 26; HPS: 3; OCA4: 1. Follow-up ranged from 3–13 years. Progressive visual acuity improvement was seen in all three main groups. T-test paired samples showed a statistically significant improvement when comparing vision from Visit 1 and Visit 3 in both OCA1A and OCA2 groups, with a mean vision improvement of 2 lines. There was no correlation between visual improvement and refractive error, eye muscle surgery or nystagmus.
Conclusion
An improved visual performance was seen in a large percentage of children with albinism during the second decade of life. The reason for this late improvement in vision is not clear but may be related to late foveal maturation or improvement in nystagmus with time. This information is useful for clinicians of these patients and when counseling parents.