Anterior chamber depth and refractive change in late postoperative capsular bag distension syndrome: a retrospective analysis

Abstract

Purpose: To assess the characteristic findings and effects of laser capsulotomy in patients with late postoperative capsular bag distension syndrome (CBDS).

Methods: Twenty patients diagnosed with late postoperative CBDS between July 2010 and August 2013 were retrospectively reviewed. Before and 1 week after capsulotomy, changes in the anterior chamber depth (ACD) were assessed using ultrasound biomicroscopy. Changes in the refractive status and uncorrected visual acuity (UCVA) were also measured 1 week and 1 month after capsulotomy. For patients who received bilateral cataract surgery, preoperative ACD and axial length measured by IOLMaster were compared between the two eyes.

Results: Twenty-two eyes from 20 patients who had undergone laser capsulotomy showed a mean UCVA improvement of 0.27 ± 0.24 logMAR (range, 0.00-0.90). ACD was increased by an average of +0.04 mm (95% confidence interval, +0.01 to +0.06 mm, p = 0.034), equivalent to predicted refractive change of +0.10 D. The discrepancy between actual (+1.33 D) and predicted refractive change after capsulotomy suggests that refractive change may not be generated from IOL displacement in late postoperative CBDS. Preoperative ACD was deeper in the eye with late postoperative CBDS in all bilaterally pseudophakic patients (mean, 3.68 mm vs. 3.44 mm in the fellow eye, p = 0.068).

Conclusions: Late postoperative CBDS showed refractive changes that were resolved successfully after laser capsulotomy. The convex lens effects of opalescent material in the distended capsular bag may play a major role in myopic shift. A larger preoperative ACD is possibly associated with the development of late postoperative CBDS.

Fig 1. Refractive status in late postoperative capsular bag distension syndrome.

The averaged refractive error in late postoperative capsular bag distension syndrome were shown with 95% confidence interval. Each measurement was performed at 2 months after cataract surgery (postoperative), before laser capsulotomy (pre-capsulotomy), and 1 week after laser capsulotomy (post-capsulotomy).

Fig 2. Comparison of spherical equivalent changes in late postoperative capsular bag distension syndrome.

Predicted spherical equivalent change and the actual refractive error change induced by laser capsulotomy in late postoperative capsular bag distension syndrome were compared in each patient. Difference between refractive error changes suggests that refractive material in capsular bag may play a major role in the myopic shift.