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  • Ocular Biometrics Predict Progression to Angle Closure

    By Lynda Seminara
    Selected by Stephen D. McLeod, MD
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    Journal Highlights

    Ophthalmology, March 2022

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    Better tools are needed to identify patients who are at high risk of primary angle closure (PAC) or acute angle closure (AAC) and may benefit from early intervention. Using data from the Zhongshan Angle Closure Prevention trial, Xu et al. looked for potential biometric risk factors for progression and found that anterior segment (AS) OCT measurements relating to the iris and angle predicted progression to PAC or AAC.

    For this prospective study, the researchers assessed 643 treatment-naive PAC suspects. Baseline assess­ments included gonioscopy, AS-OCT imaging, and A-scan ultrasound biom­etry. Suspected PAC was defined as the inability to visualize pigmented trabec­ular meshwork in at least two quadrants, based on static gonioscopy. PAC was defined as the development of IOP above 24 mm Hg or peripheral anterior synechiae. Progression was defined as the occurrence of PAC or AAC. Multi­variable logistic regression models were applied to assess relationships between biometric risk factors and progression. The main outcome was progression of suspected PAC to actual PAC or AAC within six years.

    Progression occurred in 34 patients (5.3%). The multivariable model with continuous parameters revealed signif­icant baseline risk factors for progres­sion: narrower horizontal angle-open­ing distance (500 μm from the scleral spur [AOD500]; odds ratio [OR], 1.10 per .01-mm decrease; p = .03), flatter horizontal iris curvature (OR, 1.96 per .1-mm decrease; p = .01), and advanced age (OR, 1.11 per year; p = .01). Area under the receiver operating character­istic curve (AUC) was .73.

    When horizontal AOD500 was replaced by cumulative gonioscopy score in the multivariable model, gonioscopy findings were not associ­ated with progression (OR, 1.03 per 1-modified Shaffer grade decrease; p = .85). Patients with the highest risk of progression were in the lowest quar­tile of horizontal AOD500 (OR, 3.10; p = .002) and iris curvature (OR, 2.48; p = .014) and were older than 58 years of age (OR, 2.68; p = .01) at baseline (AUC, .72).

    These results suggest that ocular biometrics may help stratify risk for pa­tients with early signs of angle closure. Progression risk varies among PAC sus­pects, and some eyes may benefit from prophylactic treatment. The authors noted that laser peripheral iridotomy or lens extraction still may be considered, particularly for elderly patients with severe angle narrowing or iris flatten­ing. They recommend research to ex­plore biometric parameters in different populations and to devise quantitative imaging-based methods for identifying treatable PAC suspects.

    The original article can be found here.