Risk Factors Associated with Missed Diagnoses of Narrow Angles by the Van Herick Technique.

ABSTRACT

PURPOSE: To identify which factors are associated with a deep-appearing anterior chamber on slit-lamp examination by the Van Herick (VH) technique in eyes with a diagnosis of narrow angle (NA) on gonioscopy. DESIGN: Retrospective review. PARTICIPANTS: One thousand three hundred fourteen eyes in 696 participants with NA on indirect gonioscopy. METHODS: All included eyes were graded as narrow with iridotrabecular contact on indirect gonioscopy in a darkened room by a single trained glaucoma specialist. Before gonioscopy, eyes were graded as narrow or deep by VH slit-lamp examination technique. Demographic and clinical factors predictive of a deep VH grading were assessed using logistic regression with generalized estimating equations. MAIN OUTCOME MEASURES: Factors associated with deep versus narrow VH grade. RESULTS: Using the VH technique, 13.7% of eyes (n = 180/1314) with NA on gonioscopy were classified as deep. Eyes with primary angle-closure glaucoma (PACG; odds ratio, 2.43; P < 0.001) and primary angle closure (PAC; odds ratio, 1.38; P = 0.006) were significantly more likely to be graded as deep by the VH technique relative to eyes that were primary angle-closure suspects (PACSs). In multivariate analysis, male gender (odds ratio, 2.22; P < 0.001), myopia (odds ratio, 1.4; P = 0.048), and black (odds ratio, 4.11; P < 0.001) and Asian (odds ratio, 2.24; P = 0.044) race were independent risk factors for a deep grading with the VH technique in eyes with NA on gonioscopy. CONCLUSIONS: Patients with NAs on gonioscopy who are men, myopic, and of black or Asian race are at increased risk of being misdiagnosed with deep angles if examined with the VH technique alone. Eyes with PACG and PAC may be more likely than those with PACS to be misdiagnosed as deep with the VH technique. It is possible that by being missed by the VH technique, these eyes could have progressed from PACS to PAC and PACG. Patients with these demographic and clinical characteristics in the presence of other risk factors for glaucoma should undergo careful gonioscopy.