Risk factors for incident nuclear opacities

Abstract

Purpose: To evaluate risk factors for the 4-year incidence of nuclear opacities.

Design: Population-based cohort study (85% participation at 4-year follow-up).

Participants: Two thousand six hundred nine black participants of the Barbados Eye Studies, without any nuclear opacities at baseline.

Methods: Participants completed a standardized protocol at baseline and follow-up, including ophthalmic and other measurements, an interview, slit-lamp lens grading, fundus photography, and an ophthalmologic examination. Factors associated with the incidence of nuclear opacities (Lens Opacities Classification System II N > or = 2) were evaluated by logistic regression.

Main outcome measure: Relative risks (RR) with 95% confidence intervals (95% CI).

Results: The 4-year incidence of nuclear opacities was 9.2% (241 of 2609) and increased greatly with age. Women were at significantly greater risk (RR = 1.8), as were persons with darker iris color (RR = 4.9), myopia (RR = 2.8), history of diabetes (RR = 1.6), leaner body mass (RR = 0.95 for each unit increase in body mass index [kg/m(2)]), and intraocular pressure (IOP)-lowering treatment (RR = 2.7), mainly with topical beta-blockers. Treated participants had a threefold RR of nuclear opacities (RR = 3.2; 95% CI, 1.6, 6.5) compared with those untreated and with IOP < or =21 mmHg. Among participants with IOP >21 mmHg, those receiving treatment (n = 33) had a fivefold RR (RR = 5.0; 95% CI, 1.7, 15.1) versus those who were untreated. The RR was similar for treated persons with and without open-angle glaucoma (RR = 3.1; 95% CI, 1.3, 7.4 and RR = 2.8; 95% CI, 0.9, 8.6 respectively) but was lower in persons with newly detected (and thus untreated) glaucoma at baseline (RR = 1.2; 95% CI, 0.6, 2.6) compared with those without open-angle glaucoma or treatment.

Conclusions: The 4-year risk of nuclear opacities increased with age, female gender, darker iris color, myopia, diabetes, and leaner body mass, indicating similarities with other populations. The use of topical IOP-lowering medications tripled the RR of nuclear opacities in this study, an association that requires verification from clinical trials.