Effect of Visibility of the Ciliary Body Processes on Ocular Biometric Parameters in Patients with Primary Angle Closure

Lens factor as an underlying mechanism in primary angle closure with gonioscopically-visualized ciliary body processes

PURPOSE

To compare the differences in anterior segment parameters between eyes with primary angle closure (PAC) with and without gonioscopically-visualized ciliary body processes (CBP).

STUDY DESIGN

Prospective, observational, comparative clinical study.

METHODS

Detailed ocular examinations and gonioscopy were performed in 89 eyes of 89 patients with PAC to determine the visibility of the CBP. Anterior chamber depth (ACD), anterior chamber width, lens thickness (LT), lens vault (LV) and pupil diameter were determined using ultrasound biomicroscopy. The lens-axial length factor (LAF) and relative lens position (RLP) were calculated. All parameters were compared between eyes with and without gonioscopically visible CBP (PAC+CBP and PAC-CBP groups) after adjusting for age and gender. The association of the parameters with visible CBP was analyzed by univariate logistic regression analysis.

RESULTS

PAC+CBP group included 41 eyes and the PAC-CBP group, 48 eyes. The axial length and ACD were statistically significantly smaller (p = 0.009 and p = 0.005, respectively) and LT, LV and LAF were statistically significantly greater (p = 0.03, p = 0.008 and p = 0.004, respectively) in the PAC+CBP group. In the PAC eyes with glaucoma, the LT, LV and LAF were statistically significantly greater in the PAC+CBP group (p = 0.02, p = 0.001 and p = 0.02, respectively). The LAF had the strongest association with visible CBP in the regression analysis (Odds ratio = 141.70, p = 0.002).

CONCLUSION

Gonioscopical visualization of ciliary processes may suggest that anterior segment crowding, especially lens factor is the underlying mechanism in PAC. It may provide a practical gonioscopic examination method for predicting the predominant pathophysiology of PAC.

Factors defining the intraocular pressure-lowering effect of phacoemulsification and laser peripheral iridotomy in patients with primary angle closure : Factors defining IOP lowering effect of PE and LPI in PAC

To identify whether gonioscopic ciliary body visibility and factors including anterior chamber depth (ACD), axial length (AL), acute attack history, and preoperative intraocular pressure (IOP) had any effect on IOP decrease in primary angle closure (PAC) and primary angle-closure glaucoma (PACG) after phacoemulsification (PE) and/or laser peripheral iridotomy (LPI). This retrospective-design study was conducted with 81 eyes with PAC and PACG; 33 eyes whose IOP was controlled with LPI and PE constituted group 1, and 48 eyes whose IOP was controlled using LPI alone comprised group 2. The effects on preoperative and last-visit IOP levels, ciliary body visibility, ACD, AL, and acute attacks were analyzed. Eyes within the groups were similar in AL, ACD, and preoperative IOP except for acute attack history, which was found to be higher in group 1. For group 1, none of the factors was found to have a differentiative effect on IOP decrease after PE, except eyes with preoperative IOP > 21 mm Hg, which had significantly more IOP reduction. For group 2, no difference was found in ciliary body visibility, and higher or lower ACD. However, eyes with AL ≥ 22 mm, positive acute attack history, and higher preoperative IOP were associated with significantly better IOP reduction. We found no relationship between ciliary body visibility and an IOP-reducing effect of PE and LPI. Although we found PE effective in IOP reduction in all eyes, we determined LPI to have a lesser IOP-reducing effect in eyes with IOP ≤ 21 mm Hg and AL < 22 mm.