Comparison of uveal parameters between acute primary angle-closure eyes and fellow eyes in South Indian population

Purpose: To analyze the ocular biometric parameters of eyes with acute primary angle closure (APAC) as compared to fellow eyes. Methods: A cross-sectional study was conducted on 27 patients presenting with recent onset APAC to a tertiary eye institute in India. Anterior and posterior ocular biometric parameters were measured simultaneously by anterior segment optical coherence tomography (AS-OCT), A-scan, ultrasound biomicroscopy (UBM), and B-mode ultrasonogram (USG). The parameters measured were anterior chamber depth (ACD), anterior chamber angle (ACA), angle opening distance (AOD500, AOD750), lens vault (LV), axial length (AL), ciliary body thickness maximum (CBTmax) and at the point of scleral spur (CBT0), anterior placement of the ciliary body (APCB), and retinochoroidal thickness (RCS). Results: Mean age +/- SD of patients with APAC was 55.66 +/- 7.2 years with female preponderance (21:6 patients). Mean presenting IOP +/- SD of the affected eye and fellow eye were 54.74 +/- 11.67 mm Hg and 18.7 +/- 11.67 mm Hg, respectively. Eyes with APAC had statistically significant narrower anterior ocular biometric parameters, higher LV, decreased ciliary body thickness, more APCB, and longer AL than the fellow eyes. CBTmax is the only variable that had significance (beta = -0.421,95% CI: -0.806 to - 0.035, P = 0.034) in the univariate analysis with RCS thickness in APAC eyes. Further, there was a correlation between CBT0 and APCB with CBTmax both in univariate (beta = 0.894, P < 0.0001 and beta = -0.351, P = 0.039) and multivariable analysis (beta = 0.911, P < 0.0001 and beta = -0.416, P = 0.016). Conclusion: Compared to the fellow eyes, APAC eyes had different ocular biometric parameters. In addition to known biometric parameters associated with pupillary block (narrower anterior biometric parameters-ACA, ACD, and AOD), our study found multiple nonpupillary block factors such as higher lens vault and thinner and more anteriorly placed ciliary body to be associated with APAC.