Prevalence and contribution of pterygium in visual impairment and blindness in older adults: the Brazilian Amazon Region Eye Survey (BARES)

Abstract

Purpose : Pterygium is an ophthalmic disease strongly related to ocular sun exposure. Our purpose was to determine the prevalence of pterygium and its contribution to visual impairment and blindness in older adults living in a high ultra-violet (UV) exposure area, the city of Parintins in the Brazilian Amazon Region.

Methods : BARES is a population-based cross sectional study conducted using cluster random sampling, to enumerate subjects 45 years of age and older. Eligible subjects were enumerated through a door-to-door household survey and invited for an eye exam. Pterygium was assessed in each eye by ophthalmologists through slit-lamp examination considering its location (nasal, temporal or both), size (> 3mm) and pupillary invasion. Visual impairment was considered as best-corrected visual acuity (BCVA) <20/63 and blindness BCVA <20/200. Associations of pterygium with gender, age, education and local of residence (urban or rural) were investigated.

Results : A total of 2384 eligible persons were enumerated and 2041 (85.6%) were examined. The prevalence of any type of pterygium in either eye was 58.7% [95% Confidence Interval (CI): 56.6% – 60.9%] and for bilateral pterygium was 39.2% [95%CI: 37.1% – 41.4%]. Previous pterygium excision was present in 122 (3.0%) eyes with recurrence in 72 (59.0%) eyes. The prevalence of pterygium as cause of visual impairment and blindness was 14.3% and 3.9%, respectively. Male gender [OR=1.69; 95%CI: 1.35-1.94; p=0.001] was associated to the presence of pterygium in either eye. Older age [OR=2.01; 95%CI: 1.40-2.89; p=0.001] and rural area [OR=1.64; 95%CI: 1.16-2.30; p=0.008] were associated to pterygium >3mm in either eye. Older age [OR=3.66; 95%CI: 1.91-7.04; p=0.001] was associated with pterygium invading the pupil. Male gender [OR=1.59; 95%CI: 1.20-2.10; p=0.003] and rural area [OR=1.61; 95%CI: 1.03-2.51; p=0.006] were associated to the presence of pterygium in both nasal and temporal sides simultaneously.

Conclusions : Pterygium was highly prevalent in older adults and might cause visual impairment and blindness even when the best refractive correction is provided. These findings reinforce the need of strategic actions to prevent and to provide services for early diagnosis and treatment of this disease with emphasis in older males living in rural areas of the Brazilian Amazon Region.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.