Racial and Sociodemographic Disparities in Blindness Associated with Primary Angle Closure Glaucoma in the United States: An IRIS^® Registry Analysis

Abstract

Purpose: To assess the prevalence and risk factors of blindness among patients newly diagnosed with primary angle closure glaucoma (PACG) in the United States (US). Design: Retrospective cross-sectional study of patients from the American Academy of Ophthalmology IRIS® (Intelligent Research in Sight) Registry. Participants: Patients in the IRIS® Registry between the years 2015 to 2019 with a new diagnosis of PACG and visual acuity (VA) data on or within 90 days prior to the date of diagnosis. Methods: Eligible patients were aged 18 years and older and: (1) were observable in the database at least 24 months prior to the index date of PACG diagnosis; (2) had no history of intraocular pressure (IOP) lowering drops, laser peripheral iridotomy (LPI), cataract surgery, or a diagnosis of pseudophakia unless preceded by a diagnosis of anatomical narrow angle (ANA); and (3) had no history of glaucoma surgery. Multivariable logistic regression models were developed to assess risk factors of blindness. Main Outcome Measures: Any (one or both eyes) or bilateral (both eyes) blindness (VA ≤ 20/200) at first diagnosis of PACG. Results: 43,901 patients with PACG in the IRIS® Registry met inclusion criteria. Overall prevalence of any and bilateral blindness were 11.5% and 1.8%, respectively. Black and Hispanic patients were at higher risk of any (OR=1.42 and 1.21, respectively; p<0.001) and bilateral (OR=2.04 and 1.53, respectively; p<0.001) blindness compared to non-Hispanic White patients adjusted for ocular comorbidities, including cataracts. Other factors associated with any blindness included age <50 or >80 years, male sex, Medicaid or Medicare insurance category, and Southern or Western practice region (ORs>1.28; p≤0.01). Diagnosis of ANA prior to diagnosis of PACG was protective against any (OR=0.56; p<0.001) and bilateral (OR=0.61; p<0.001) blindness. Conclusions: Blindness affects 1 out of 9 patients with newly diagnosed PACG in the IRIS® Registry; Black and Hispanic patients and Medicaid and Medicare recipients are significantly more vulnerable. These findings highlight the severe ocular morbidity associated with PACG and the need for increased disease awareness and improved detection methods.