Clinical Study
Eye (2006) 20, 533–536. doi:10.1038/sj.eye.6701917; published online 13 May 2005
Prevalence of pterygium and cataract in indigenous populations of the Brazilian Amazon rain forest
Financial support: CAPES.
J S Paula1, F Thorn2 and A A V Cruz1
- 1School of Medicine of Ribeirão Preto, USP, Brazil
- 2New England College of Optometry, Boston, MA
Correspondence: JS de Paula, Departamento de Oftalmologia, Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Hospital das Clínicas de Ribeirão Preto, 12° andar, Campus USP Av. Bandeirantes, 3900, 14.049–900, Ribeirão Preto, São Paulo, Brazil. Tel: +55 16 602 2499; Fax: +55 16 602 2860; E-mail: jayterdepaula@yahoo.com.br
Received 16 December 2004; Revised 21 March 2005; Accepted 21 March 2005; Published online 13 May 2005.
Abstract
Purpose
To compare the prevalence of pterygium and cataract in four indigenous populations of the Brazilian Amazonian rain forest (Arawak, Tukano, Maku, and Yanomami) with different ethnic and social behaviour backgrounds.
Methods
A cross-sectional pterygium and cataract survey was performed in 624 adult Indians of the Brazilian rain forest belonging to four different ethnic groups. The Indians were classified according to their social behaviour in two groups: Arawak and Tukano (group 1) and Maku and Yanomami (group 2). Slit-lamp biomicroscopy was employed to examine the entire sample. All subjects were classified as 1 or 0 according to the presence or absence pterygium and cataract. Sex and age were also recorded.
Results
2-tests revealed that the prevalence of pterygium and cataract differed significantly between groups 1 and 2. For pterygia: 36.6% (97/265) and 5.0% (18/359), respectively (2=101.2, P<0.0001), and for cataracts: 24.5% (65/265) and 13.7% (49/359) respectively (2=12.09, P=0.0005). Gender was not associated with pterygium (P=0.1326) and cataract (P=0.2263) in both groups. Elderly subjects showed a significantly higher prevalence of cataract (P<0.0001). The prevalence of pterygia did not increase with age (P=0.8079) in both groups.
Conclusion
Indians of group 1 have higher prevalence of pterygia and cataract than Indians of group 2. Social behaviour, especially the rate of sun exposure, appears to be the main factor for the different rates of pterygium and cataract displayed by these indigenous people of the Brazilian rain forest.
Keywords:
pterygium, cataract, Amerindians, epidemiology, sun exposure
