Age of lens use onset in a myopic sample of office-workers

Purpose. The present study was developed to assess prevalence of myopic refractive error and the relative percentages of youth- and adult-onset myopia in a Caucasian adult population. Methods. Subjects were office-workers sent consecutively from their workplace for a general health check-up, without refractive selection. Each subject received a questionnaire about academic achievement and family history of myopia. Subsequently, an ophthalmologist performed the vision examination. Although age of initial lens use is not necessarily the same as age of onset of myopia, it was considered to be so for this paper. A subject was considered an adult-onset myope if lens use began at age 18 or later. Results. Subjects (n=349) had a mean age of 37.6+/-9.3 years. One hundred seventeen subjects (33.5% prevalence) had myopic spherical equivalent refraction. Further analysis comprises only subjects with simple myopia (astigmatism <1 diopter, n=95). Nearly half of the simple myopic subjects were of adult-onset (47.8%). There was no difference in family history of myopia between youth- and adult-onset myopes (at least one myopic parent in 53.1% and 47.8% respectively, p=0.53), and no clear cut-off point separated the two myopic subgroups with respect to the age of lens use onset. However, adult-onset myopes had myopia of lower diopter amount than youth-onset myopes. Conclusions. Adult-onset myopes comprised nearly half of the simple myopic subjects, and their family history of myopia was similar to that of youth-onset myopes. There is no clear cut-off point between both myopic subgroups when age of onset is the variable considered.