Adult Myopia Progression.

PURPOSE

To explore evidence for myopic shift between the ages of 20 and 50 years.

METHODS

Three usable sets of data with long-term adult refractive progression were identified: (1) US population-based prevalence data for those 18 to 24 years of age in 1971 and 1972 and 45 to 54 years of age from 1999 to 2004; a logit transformation of prevalence values at different refractive error thresholds allowed estimation of myopic progression in this group. (2) German clinical data describing 5- to 10-year progression for different refractive error groupings across 5-year age bands from 20 to 49 years; these were extracted, adjusted, and analyzed. (3) Five-year progression rates with similar breakdown of age and refractive error groups as the German data but in a Japanese clinical population.

RESULTS

Estimates of progression between 20 and 50 years for the given studies were: (1) -1.1, -1.4, and -1.9 diopters (D) for baseline refractive errors of -1, -3, and -6 D, respectively; (2) a range from -1.0 to -2.9 D, increasing with degree of baseline myopia; (3) a weighted average of -1.0 D for males and -0.9 D for females but with decreasing progression with increasing myopia. In all studies, average progression rates fell with increasing age, with most progression occurring between 20 and 30 years.

CONCLUSIONS

All three studies provide evidence of around -1 D myopia progression between the ages of 20 and 50 years. This has implications for intervention to slow progression during adulthood, as well as projections of visual impairment associated with myopia.