Factors associated with high myopia after 7 years of follow-up in the Correction of Myopia Evaluation Trial (COMET) Cohort

Ophthalmic Epidemiol. 2007 Jul-Aug;14(4):230-7. doi: 10.1080/01658100701486459.


Purpose: To evaluate factors associated with the development of high myopia (worse than -6.00 D) over 7 years of follow-up in the COMET cohort.

Methods: COMET enrolled 469 ethnically diverse children (6-11 years) with myopia between -1.25 and -4.50 D. They were randomized to either progressive addition lenses (PALs) or single vision lenses (SVLs), and followed for 5 years in their original lens assignment and 2 additional years wearing either spectacles (PALs or SVLs) or contact lenses. Refractive error was measured annually by cycloplegic autorefraction and axial length by A-Scan ultrasonography. Myopia for each child was defined as the mean spherical equivalent refractive error (SER) of the 2 eyes. Analyses were based on 7 years of follow-up. Time to high myopia was analyzed by Cox proportional hazard models and linear regression. Parental refraction data were available from 240 COMET subjects.

Results: Younger (6-7 years) versus older (11 years) age at baseline was a significant risk factor (adjusted hazard ratio (HR) = 6.6, 95% CI = 3.4, 12.7) for having high myopia within 7 years. More (SER from -2.26 to -4.50 D) vs. less (SER from -1.25 to -2.25 D) baseline myopia was also a significant risk factor for high myopia at 7 years (adjusted HR = 7.4, 95% CI = 4.4, 12.4). Gender, ethnicity, and treatment assignment were not associated with the risk of high myopia within 7 years. Increased number of myopic parents was associated with a significant risk of high myopia in the children (p = 0.008).

Conclusions: Children who developed high myopia during 7 years of follow-up were younger and had more myopia at baseline. They also were more likely to have two myopic parents. These children may be at greater risk for sight-threatening conditions later in life.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Disease Progression
  • Eyeglasses*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Myopia, Degenerative / etiology*
  • Myopia, Degenerative / therapy*
  • Proportional Hazards Models
  • Prospective Studies
  • Risk Factors