Large optic disks in the Marshallese population.

On routine examination, asymptomatic patients from the Marshall Islands were noted to have large optic disks associated with high cup/disk ratios and normal intraocular pressure. We retrospectively analyzed color fundus photographs of 54 eyes and 22 eyes of 15 patients had optic disks greater than 2.10 mm, or megalopapilla. Of 36 patients with cup/disk ratios exceeding 0.6, 31 (86%) had visual acuities of better than or equal to 20/30. The optic nerve rim and disk areas varied directly as did disk and cup diameters. Three large disks with an 18-year photographic follow-up showed no change. Optic disk characteristics can vary widely among genetically isolated populations.