Outcomes of Glaucoma Referrals in Adults Aged 18 to 40 Years.

Importance: While early detection of glaucoma is vital to prevent irreversible vision loss, there are sparse data on the effectiveness of glaucoma referrals and methods to establish evidence-based referral guidelines in large, diverse populations. Objective: To assess the prevalence and risk factors for diagnosed glaucoma and loss to follow-up among adult patients aged 18 to 40 years after a new diagnosis of referable glaucoma (ie, with glaucoma or suspected glaucoma). Design, Setting, and Participants: This retrospective cohort study included patients aged 18 to 40 years presenting to Kaiser Permanente Southern California, a large managed health care system, for first-time eye examinations between January 1, 2013, and December 31, 2018. Data analysis occurred between September 2022 and August 2024. Main Outcomes and Measures: The primary outcome was glaucoma diagnosed within 2 years of the first eye examination. The secondary outcome was the loss to follow-up, defined as failure to receive a glaucoma evaluation with visual field or optical coherence tomography testing within 2 years. Results: The cohort included 292 453 patients aged 18 to 40 years who underwent first-time eye evaluations (mean [SD] age, 29.8 [6.4] years). Among 12 050 identified patients with referable glaucoma (52.3% female), 6827 (56.7%) completed glaucoma evaluations, of whom 563 (8.2%) were diagnosed with glaucoma (344 [61.1%] with open angle, 28 [5.0%] with angle closure, 84 [14.9%] with secondary glaucoma, and 107 [19.0%] with unspecified glaucoma). On multivariable analysis, male sex (odds ratio [OR], 1.55 [95% CI, 1.07-2.27]), higher intraocular pressure (IOP) (OR, 1.19 [95% CI, 1.15-1.23] per 1 mm Hg), and greater cup-disc ratio (CDR) (OR, 1.53 [95% CI, 1.34-1.75] per 0.1 unit) were associated with greater odds of glaucoma. Dichotomized age, IOP, and CDR models stratified 51 of 1613 patients (3.2%) into the low-risk group and 202 of 1477 patients (13.7%) into the high-risk group. Being younger than 32 years and having an IOP less than 18 mm Hg and a CDR less than 0.7 yielded a negative predictive value of 98.2% for a glaucoma diagnosis. Conclusions and Relevance: In this cohort study, the diagnostic yield of glaucoma referrals was low among adults aged 18 to 40 years with first-time eye examinations. A simple risk-stratification strategy could help identify individuals with low and high risks of developing glaucoma, and adoption of evidence-based risk stratification and referral guidelines by health care systems and clinicians could improve equity of glaucoma care and use of eye-care resources.