Abstract
Purpose::
Myopia prevalence has been found to be increased in populations with greater academic achievement. In this study we searched for a relationship between the number of years of University study and the amount of myopic refractive error developed.
Methods::
1518 refractively unselected consecutive adult office-workers were studied during the year 2005. They received a subjective refractive examination and a questionnaire concerning age of onset of lens use, years of University study, and parental history of myopia. Subjects with myopia onset at University study years were considered for the analysis (recalled age of onset from 18 to 30 years). The median of years of University study was 6 years. The refractive error developed was compared for subjects with high vs. low academic achievement (above or below the median).
Results::
The mean age of the whole sample was 43.2 ± 9.8 years, 81.9 % were males, 29.2 % were myopes and 18.1% were hyperopes (± 0.50 diopters criterion). The prevalence of myopia increased with greater academic achievement: 26.3 % (284/1080) for subjects with 6 or less years of study, compared to 36.3 % (159/438) for subjects with 7 or more years of study (p < 0.0001). There were 413 myopes who could recall their age first prescription, ranging from 3 to 58 years at onset. The median age of first prescription for this myopic group was 20 years (mean 20.9 ± 9.3 years). In the group of 220 myopes with onset between 18 and 30 years of age, a difference in the final refractive error developed in adulthood was observed according to academic achievement. Those subjects who had studied less than six years had 0.4 diopters less myopia than those who had studied seven years or more (average refractive error -1,86 ± 1,16 for less than 6 years vs. -2,26 ± 1,41 for seven or more years; p = 0,026). Parental history or age of onset were not related to the amount of refractive error developed.On the other hand, the 142 subjects who were already myopic at age 17 had on average a +0.8 significant difference in years studied vs. their emmetropic pairs (6.3 ± 1.9 years for myopes vs. 5.5 ± 2.0 years for emmetropes, p = 0.00002).
Conclusions::
A positive significant association was found between the final myopic refractive error developed in adulthood and the number of University study years. Those subjects who had studied more years had greater myopic refractive error. Besides, myopic subjects tend to be engaged in more years of study than emmetropes.
Keywords: myopia • clinical (human) or epidemiologic studies: risk factor assessment