Unilateral high myopia: optical components, associated factors, and visual outcomes.

AIM To elucidate the optical basis for unilateral high myopia and to identify the factors associated with its development. METHODS Medical records of 48 children (aged 4 months to 17 years; mean age 6.8 years) with unilateral high myopia (5 dioptres or more) seen consecutively by the author during a 15 year period were reviewed. 45 (94%) of the 48 patients had unilateral axial myopia. RESULTS The mean refractive difference between paired eyes was 9.4 (SD 3.6) dioptres and the more myopic eye was on average 3.3 (1.8) mm longer than the less myopic eye. All but three of the patients had an ocular disorder associated with reduced acuity, central nervous system abnormality, or family history of high myopia. CONCLUSION Clinical conditions associated with unilateral high myopia can be identified in the majority of patients and often account for the associated visual impairment.