Purpose: To evaluate ocular biometric parameters and darkroom prone provocative test (DPPT) in family members of primary angle closure (PAC) glaucoma (PACG) patients and to establish any correlation between these biometric parameters and the DPPT response.
Methods: Seventy-four family members of PACG patients underwent ultrasound ocular biometry, slit lamp biomicroscopy, Goldmann applanation tonometry, fundus examination, and gonioscopy. Lastly, DPPT was performed.
Results: Of 74 family members examined, 6 (8.1%) were found to have PAC, 8 (10.8%) were PAC suspects, and 60 (81.1%) were unaffected. Of those affected, 4 (66.7%) had a positive DPPT response, whereas 87.5% of the PAC suspects had a positive or a borderline DPPT response. Affected and PAC suspects had the shallowest anterior chamber depth, thickest lens, shortest axial length, and most anteriorly positioned lens. Anterior chamber depth and lens thickness showed a significant correlation with positive DPPT.
Conclusions: Anterior chamber depth and lens thickness and, to a lesser extent, axial length and lens position were significantly correlated with a positive DPPT response. The ocular biometric risk factors associated with PACG patients are also found in their respective family members who are affected and suspected of having PAC. We suggest a longitudinal study to determine the reliability of DPPT in identifying individuals who are at risk of PAC.