Objective quantification of posterior capsule opacification using swept-source anterior segment optical coherence tomography

Purpose: To objectively quantify posterior capsule opacification (PCO) using swept-source anterior segment optical coherence tomography (SS-ASOCT) in pseudophakic eyes. Setting: Zhongshan Ophthalmic Center, Guangzhou, China Design: Prospective cross-sectional study. Methods: One hundred and eighty eyes with PCO (37 multifocal intraocular lenses [MfIOLs] and 143 monofocal intraocular lenses [MoIOLs]) were enrolled. The PCO Irregular Degree (PID), defined to evaluate the surface irregularity of PCO, the average and maximum thickness of PCO (AT-PCO, MT-PCO) were applied to quantify PCO based on SS-ASOCT (CASIA2) images. Corrected distance visual acuity (CDVA), high order aberrations (HOAs), modulation transfer function (MTF) and Strehl ratio were recorded. The associations between SS-ASOCT parameters and visual function parameters were assessed by Spearman’s correlation analysis. Results: PID, AT-PCO and MT-PCO showed significant correlations with CDVA, Strehl ratio and HOAs (CDVA: r = 0.702, 0.741, 0.736; Strehl ratio: r = -0.746, -0.719, -0.740; HOAs: r = 0.762, 0.734, 0.752). The correlations of these three parameters with Strehl ratio and HOAs were significantly higher than those of clinical PCO grading with Strehl ratio and HOAs (all P < 0.05). Particularly, PID demonstrated notable correlations with Strehl ratio and HOAs. In addition, patients with MfIOLs presented worse Strehl ratio and HOAs than those with MoIOLs after matching age, PID, AT-PCO and MT-PCO. Conclusions: This study provides a novel method for objectively quantifying PCO using successive cross-sectional SS-ASOCT images. AT-PCO, MT-PCO and PID are presented as new indicators to document PCO severity, with PID offering a unique perspective by considering the irregularity aspect of PCO.