Safety of Pharmacologic Dilation: Incidence and Risk Factors of Acute Angle Closure in a Nationwide Cohort

To evaluate the incidence and risk factors of acute angle closure (AAC) following dilation in a nationwide healthcare claims database.

Retrospective cohort study.

Patients who underwent dilation by an ophthalmologist/optometrist between January 2007 and December 2021 were identified by Current Procedural Terminology (CPT)/Healthcare Common Procedure Coding System codes for comprehensive eye exam, extended ophthalmoscopy, or dilated fundus exam. Patients with AAC/primary angle closure glaucoma diagnosis before the first dilation were excluded.

AAC risk was assessed under two definitions. Definition 1 (more sensitive and inclusive): International Classification of Diseases code for AAC glaucoma within 14 days of dilation; Definition 2 (more specific and exclusive): Definition 1 plus CPT code for iridotomy/iridectomy or lens extraction within 14 days of AAC diagnosis. Dilations after the first AAC diagnosis were excluded. Multivariable logistic regression was performed to assess factors associated with AAC diagnosis by comparing patients who received an AAC diagnosis with those that did not.

AAC under two definitions based on International Classification of Diseases/CPT codes.

A total of 11,452,733 patients underwent 26,478,250 dilations. The incidence of AAC diagnosis per dilation was 0.01% under Definition 1 and 0.004% under Definition 2. Older age compared to <40 years (OR ≥ 3.26, P < .001), Asian race and Hispanic ethnicity compared to non-Hispanic Whites (OR ≥ 1.38, P < .001), and prior angle closure diagnosis (OR ≥ 12.74, P < .001) conferred higher odds of AAC diagnosis under both definitions. Income ≥$100,000 compared to <$40,000 (OR ≤ 0.83, P < .001), non-Northeast regions (OR ≤ 0.74, P ≤ .002), and pseudophakia status (OR ≤ 0.73, P < .001) conferred lower odds of AAC diagnosis under both definitions. Female sex (OR = 1.19, P < .001), non-HMO insurance (OR ≥ 1.19, P ≤ .006), and Black race (OR = 1.18, P = .003) conferred higher odds of AAC diagnosis under Definition 1.

In a nationwide cohort, the risk of AAC diagnosis following dilation ranged from around 1 in 7,000 to 26,000 dilations. Given the apparent safety of dilation and its importance in comprehensive eye exams and teleretinal care, further discussions regarding concerns about AAC with dilation are warranted.