Thinning of maximum ciliary body thickness: a potential early indicator for pseudophakic malignant glaucoma in primary angle closure glaucoma.

Abstract

Objective: Pseudophakic malignant glaucoma (PMG) is an uncommon but severe postoperative complication that poses a significant threat to vision. Early detection of PMG in patients with primary angle closure glaucoma (PACG) is imperative for effective intervention. This study sought to determine whether specific morphometric indicators could predict the onset of PMG.

Methods: A retrospective cross-sectional analysis was performed on data collected from June 2016 to May 2023. The study population comprised PACG patients who developed PMG after phacoemulsification, with a control group of eyes that did not. Ultrasound biomicroscopy (UBM) was employed to measure the central anterior chamber depth (ACD), trabecular-ciliary process angle (TCA), and ciliary body thickness at multiple points (CBTmax, CBT0, CBT1000), as well as the anterior placement of the ciliary body (APCB). These measurements were taken at three distinct phases: pre-onset, onset, and 6 months following PMG resolution.

Results: The study encompassed 60 eyes from 60 patients, with baseline characteristics showing no significant differences between the groups. Following lens extraction, a notable increase in CBTmax, CBT0, and TCA was observed in matched eyes, but not detected in those that developed PMG. At pre-onset of PMG, a significant reduction in CBTmax was identified exclusively in eyes that later exhibited PMG (0.87 ± 0.09 mm vs. 0.95 ± 0.09 mm, P = 0.001), when compared to the matched eyes. The resolution of PMG through zonulo-hyaloido-vitrectomy was associated with an increase in ACD, CBTmax, CBT0, and TCA. Notably, the pre-onset CBTmax was the sole parameter to exhibit significant prognostic value for PMG development (0.74 [95% CI, 0.61-0.87], P = 0.001), nearly matching the predictive accuracy during PMG attack (0.86 [95% CI, 0.76-0.96], P < 0.001).

Conclusion: A reduction in ciliary body thickness, particularly CBTmax, appears to be a pre-existing condition in eyes that develop PMG from PACG. This parameter holds promise as a sensitive early predictor, potentially improving the timeliness of PMG diagnosis and treatment.