Abstract
Purpose :
Sunlight exposure reduces the incidence and inhibits the progress of myopia yet pinguecula among young people is a chronic ocular disorder caused by UV exposure. We examined the correlation between prevalence of pinguecula and myopia among university students.
Methods :
Subjects comprised 223 university students in Ishikawa Prefecture, Japan (166 men and 57 women; mean age, 19.7±0.9 years). Early pinguecula was diagnosed by one ophthalmologist using ultraviolet fluorescence photography, and ocular refraction measured using an open-field auto-refractor (Shigiya Machinery Works Ltd., Japan). Participants completed a questionnaire about mean time per day spent on outdoor activities from elementary school to present time, use of eye protection (spectacles, hats) and parental myopia. Odds ratios were computed using logistic regression modeling to assess correlations among age, sex, parental myopia, mean time spent on outdoor activities and with or without pinguecula.
Results :
Prevalence of early pinguecula was 39.5% and 43.9% in the temporal and nasal conjunctiva, respectively. That by reported time spent on outdoor activities was 19.6% and 16.1% for less than 2 h, 44.7% and 52.2% for 4 to 6 h, respectively and 75.0% in both fields for more than 6 h, indicating a positive correlation between prevalence of pinguecula and time spent on outdoor activities. Mean refractive power was -1.87±1.98D for those with pinguecula and -2.68±2.67D for those without (P<0.05). Risk of myopia over -0.5D increased 2.31-fold in those with a myopic father, 3.76-fold in those with a myopic mother, and 2.49-fold in those with both. Risk of myopia over -3.0D increased 4.5-fold in those with a myopic mother, 0.28-fold in those who spent more time on outdoor activities, and 0.47-fold in those with pinguecula in the nasal field (P<0.05).
Conclusions :
Increased UV exposure was associated with higher prevalence of pinguecula. This indicates a correlation between prevalence of pinguecula and sunlight exposure. Particularly, pinguecula in the nasal field was significantly correlated with decreased risks of moderate to severe myopia.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.