Pterygium and conjunctival ultraviolet autofluorescence in young Australian adults: the Raine study.

BACKGROUND: Sun exposure is associated with several ophthalmic diseases, including pterygium which may develop in adolescence. This study reports the prevalence of pterygium and its associations in a large cohort of young Australian adults. Conjunctival ultraviolet autofluorescence, a biomarker of ocular sun exposure, has recently been characterized in some Australian populations. DESIGN: Cross-sectional population-based study. PARTICIPANTS: One thousand three hundred forty-four subjects aged 18-22 years in the Western Australian Pregnancy Cohort (Raine) Study. METHODS: Standardized colour and ultraviolet autofluorescence photographs of the nasal and temporal conjunctiva were taken, and assessed for presence of pterygium and area of autofluorescence. Sun exposure and protective factors were assessed by structured questionnaire. MAIN OUTCOME MEASURES: Area of conjunctival ultraviolet autofluorescence in square millimetre (mm(2)) and presence of pterygium. RESULTS: Median total conjunctival autofluorescence was 44.2 mm(2) (interquartile range 20.2-69.8 mm(2)). Median conjunctival autofluorescence was higher in nasal than in temporal quadrants (23.8 mm(2) vs. 18.9 mm(2), P < 0.001), but did not differ according to age or gender. Higher body mass index was associated with lower levels of autofluorescence. Total autofluorescence increased with increasing time spent outdoors. Prevalence of pterygium was 1.2% (95% confidence interval 0.6-1.8%), and was associated with male gender (odds ratio 6.71, P = 0.012). Participants with pterygium had significantly more conjunctival autofluorescence than those without (median 73.4 mm(2) vs. 44.0 mm(2), P = 0.001). CONCLUSIONS: Conjunctival ultraviolet autofluorescence is associated with increased time spent outdoors, and increased prevalence of pterygium. The association of this biomarker with other ophthalmohelioses, including cataract, ocular surface squamous neoplasia and eyelid malignancy, has yet to be determined.

Myopia in young adults is inversely related to an objective marker of ocular sun exposure: the Western Australian Raine cohort study.

PURPOSE: To determine the association between ocular sun exposure measured by conjunctival ultraviolet (UV) autofluorescence and myopic refractive error in young adults. DESIGN: Cross-sectional study. METHODS: setting: Population-based cohort in Western Australia. study population: Total of 1344 mostly white subjects aged 19-22 years in the Western Australian Pregnancy Cohort (Raine) Eye Health Study. observation procedures: Cycloplegic autorefraction, conjunctival ultraviolet autofluorescence photography, participant questionnaire. main outcome measures: Prevalence of myopic refractive error (spherical equivalent less than -0.50 diopters) and area of conjunctival ultraviolet autofluorescence in mm(2). RESULTS: There was an inverse relationship between myopic refractive error and ocular sun exposure, with more than double the prevalence of myopia in the lowest quartile of conjunctival autofluorescence than the highest quartile (33.0% vs 15.6%). Median area of autofluorescence was significantly lower in myopic than in nonmyopic subjects (31.9 mm(2) vs 47.9 mm(2), P < .001). These differences remained significant after adjustment for age, sex, parental history of myopia, and subject level of education. The use of corrective lenses did not explain the lower conjunctival autofluorescence observed in myopic subjects. CONCLUSIONS: In this young adult population, myopic refractive error was inversely associated with objectively measured ocular sun exposure, even after adjustment for potential confounders. This further supports the inverse association between outdoor activity and myopia.