AIMS/BACKGROUND: This study was undertaken to document visual function and acuity in patients with Aicardi syndrome, and to determine whether there is any relation between ocular features of the syndrome exhibited at birth and later visual function. METHODS: Fourteen patients with Aicardi syndrome, all examined and followed by the same ophthalmologist, were reviewed between 1975 and 1992 and their ocular characteristics and visual acuity described. It was hypothesised that larger lacunae may be associated with poorer clinical outcome and therefore the relation between these two variables was investigated. RESULTS: Visual acuity as documented by Snellen, Sheridan-Gardner, preferential looking, or pattern visual evoked potential tests was in the normal to low normal range in six eyes of four patients. Visual function correlated significantly with macular appearance. Good visual function was preserved if the fovea appeared normal on funduscopic examination and was uninvolved by lacunae. The size of the largest chorioretinal lacuna also correlated significantly with clinical outcome: patients with large lacunae were more likely to be immobile and to have no language skills. CONCLUSION: It was concluded that good visual function in patients with Aicardi syndrome may be anticipated if the fovea is normal. Although many patients have severe psychomotor retardation, the presence of predominantly small chorioretinal lacunae may indicate a better prognosis for mobility and language development.