Substance use disorder and the risk of open-angle glaucoma

PURPOSE: To test the hypothesis that cocaine use (abuse and/or dependency) is associated with open-angle glaucoma. METHODS: A case-control study. Potential case patients were identified from the Veterans Health Administration national clinical database using International Classification of Disease, Version 9, Clinical Modification for open-angle glaucoma for fiscal year 2009. Inclusion criteria included consecutive prescriptions for 1 or more topical antiglaucoma medications. Cocaine exposure was identified through International Classification of Disease, Version 9, Clinical Modification codes. The odds of cocaine exposure were compared with the overall outpatient population of national Veterans Health Administration beneficiaries and adjusted for age and other illicit drug use. A nested case-control study was conducted to examine the confounding influence of race. RESULTS: Age-adjusted odds ratios of cocaine exposure among patients with glaucoma were statistically significant for both men [3.52 (95% confidence interval, CI: 3.21-3.86)] and women [1.87 (95% CI: 1.79-1.96)], and did not change significantly when analyzed according to drug-dependency status. Subset analysis adjusted for age, other illicit drugs, and race remained significant for men [1.45 (95% CI: 1.27-1.66)], but not women. Persons with substance use disorder and glaucoma were nearly 18 years younger than glaucoma patients without a drug exposure history. CONCLUSIONS: This pilot study suggests the use of cocaine and possibly other illicit drugs are predictive of glaucoma. Should the association of substance use disorder (cocaine or cocaine/poly-drug abuse) and open-angle glaucoma be verified, it represents a potentially modifiable risk factor for vision loss.