Age of First Distance Prescription and Final Myopic Refractive Error

PURPOSE: This study explores the relationship between the recalled age of first distance prescription and the final myopic refractive error developed in adults. METHODS: Adult office workers, sent for a general health check-up without refractive selection, completed a questionnaire about age of first distance prescription, years of university study, and parental history of myopia, and were subjectively refracted by an ophthalmologist. RESULTS: Average age of the 397 consecutive myopic subjects was 42.6 +/- 9.6 years and 80.6% were males. The median age of first prescription was 20 years. In the group with earlier first distance prescription (ages 3 to 10), 25.6% developed low final refractive errors (-0.50 to -3.0 diopters), 38.5% developed moderate myopia (< -3.0 to -6.0 diopters), and 35.9% developed high myopia (< -6.0 diopters), while in the groups with later first distance prescription (ages 23 to 30), 90-100% developed low final refractive errors. CONCLUSIONS: Subjects developing myopia after age 20 had low myopia. Those subjects with an early recalled age of first prescription had a broad spectrum of myopic refractive errors, including a high proportion (approximately 2/3) of moderate to high myopia, and approximately 1/3 of low myopia.