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Large optic disks in the Marshallese population.

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Large optic disks and high cup-to-disk ratios were found in asymptomatic Marshallese patients. These findings in megalopapilla suggest wide variations in optic nerve characteristics within isolated populations.

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Area of Science:

  • Ophthalmology
  • Optometry
  • Population Genetics

Background:

  • Asymptomatic patients from the Marshall Islands presented with unusually large optic disks and high cup/disk ratios.
  • Intraocular pressure was noted to be within normal limits in these individuals.

Purpose of the Study:

  • To retrospectively analyze the optic disk characteristics of Marshallese patients.
  • To investigate the prevalence and features of megalopapilla in this population.

Main Methods:

  • Retrospective analysis of color fundus photographs from 54 eyes.
  • Measurement of optic disk size, cup/disk ratios, and visual acuity.
  • Inclusion criteria: optic disk diameter > 2.10 mm or cup/disk ratio > 0.6.

Main Results:

  • Fifteen patients had optic disks greater than 2.10 mm (megalopapilla).
  • Of 36 patients with cup/disk ratios exceeding 0.6, 86% had visual acuity of 20/30 or better.
  • Optic nerve rim and disk areas correlated with disk and cup diameters; no changes observed over 18 years in three cases.

Conclusions:

  • Optic disk size and morphology can exhibit significant variation in genetically isolated populations.
  • Megalopapilla and high cup/disk ratios in this cohort were not associated with impaired visual acuity.
  • Findings highlight the importance of considering population-specific variations in optic nerve characteristics.