Ophthalmological examination and imaging features that better predict risk of Angle Closure in siblings.

Objective: Characteristics of individuals with angle closure may be useful in targeted screening of family members. Here, we assess if findings gathered during examination and imaging of patients with a known angle closure diagnosis (probands) could better determine the risk of angle closure in the patients' siblings.

Design: Cross-sectional study of patients with known angle closure and their siblings.

Subjects: Participants, and Controls: South Indian patients (probands) 30 years and older with open angles, suspect primary angle closure (PACS), or primary angle closure/primary angle closure glaucoma (PAC/PACG), and a biological sibling age 30 years or older (n=292 proband/sibling pairs).

Methods: Demographic data, relevant ocular history, and a comprehensive ophthalmic examination with Anterior Segment Optical Coherence Tomography (ASOCT) were obtained. Three clinically relevant models were created to analyze the contribution of specific proband factors in predicting sibling angle closure diagnosis, using demographic (age, gender), ocular exam (gonioscopy, optic nerve exam, visual acuity, intraocular pressure [IOP]), and ASOCT features to improve prediction beyond proband diagnosis alone evaluated by log likelihood ratio testing and statistical comparison of receiver operating characteristics (ROC).

Main outcome measures: Sibling angle closure diagnostic accuracy.

Results: Demographic and ocular exam metrics did not improve the prediction of sibling angle closure for all three outcomes (sibling diagnosis: (1) PACS/PAC/PACG vs OA, (2) PAC/PACG vs PACS/OA, and (3) PAC/PACG vs PACS), adding no model improvement when compared to diagnosis alone. Models adding ASOCT metrics to the prior model including proband diagnosis, demographics and ocular exam measures led to significantly improved prediction of 2 of the 3 angle closure outcomes. Specifically, improvement was noted via likelihood ratio testing for prediction of PAC/PACG vs PACS/OA (p=0.01), or PAC/PACG vs PACS (p=0.001). For all 3 angle closure outcomes, ROC comparisons demonstrated significant improvement in AUC between the three models predicting sibling outcomes, demonstrating an increase in AUC with each successive nested model across all 3 sibling angle closure outcomes.

Conclusions: Structural features of eyes with angle closure may assist in stratifying the risk of angle closure in patients' siblings. Further studies should consider evaluating this approach to achieve more targeted screenings.