Prevalence of pinguecula in children living in rural Tanzania

Abstract

Purpose: Prevalence of pinguecula in children of rural Tanzania and its correlation with ocular UV exposure were investigated using ultraviolet fluorescence photography (UVFP).

Methods: Of 232 children in Mkuranga district, 227 (age 5 to 18 yrs) were eligible to be examined with UVFP in August 2014. The 92 boys and 135 girls comprised 130 primary school students and 97 secondary school students. Pinguecula was diagnosed by slitlamp examination and from a UVFP system with UV transmission filters (transmission range 300-400 nm, peak 365 nm) as the excitation source in the temporal and nasal conjunctiva. The diagnoses by slitlamp and UVFP were performed independently by a skilled doctor and another doctor, respectively.

Results: Pinguecula were observed in 66 eyes (29.1%) by slitlamp examination, and prevalence rate significantly increased with age (p<0.01). All cases of pinguecula diagnosed by slitlamp were detected in UVFP too. Pinguecula positive findings in UVFP were 96.9% and did not significantly differ between boys (96.7%) and girls (97.0%). Prevalence of pinguecula by school grade was 80.0% in primary grade 1, 95.2% in grade 2, 90.0% in grade 3, 100% in grade 4, 100% in grade 5, 94.4% in grade 6, 100% in grade 7, and 100% in all secondary grades, respectively. Presence of pinguecula was more prevalent in nasal conjunctiva (95.4%) than in temporal (76.2%). In primary grade 1-3, presence of pinguecula was significantly higher in nasal conjunctiva (83.9%) than in temporal (48.2%), (p<0.001).

Conclusions: It was revealed that children in rural Tanzania, whose UV intensity is about 2-fold that in Japan, have an extremely high prevalence of pinguecula. This result suggests that high-rate of ocular UV exposure in children is a risk factor for high-rate of UV-related ocular disease in adults, thus, it is necessary to enlighten children about the need to protect their eyes from sunlight as a countermeasure.