Sun exposure as a risk factor for nuclear cataract

Background: Cataracts are the leading cause of blindness and visual impairment throughout the world. An association of sun exposure with cortical cataract has been well established, but the association with nuclear cataract remains unclear. Methods: This case-control study was nested within the Nambour (Australia) Trial of Skin Cancer Prevention conducted between 1992 and 1996. We compared 195 cases who had a nuclear opacity of grade 2.0 or greater with 159 controls. Structured questionnaires were used to ascertain lifetime sun exposure history, eyeglasses and sunglasses use, and potentially confounding variables such as education and smoking. Results: There was a strong positive association of occupational sun exposure between the ages of 20 and 29 years with nuclear cataract (odds ratio = 5.9; 95% confidence interval = 2.1-17.1). Exposure later in life resulted in weaker associations. Wearing sunglasses, particularly during these early years, afforded some protective effect. Conclusions: This study provides new evidence to support a link between sun exposure and nuclear cataract. Risk was highest among those with high sun exposure at younger ages.