Effects of Nd: YAG laser capsulotomy on central macular thickness: a systematic review and meta-analysis

This study presents the first systematic review and meta-analysis evaluating central macular thickness (CMT) changes following Nd: YAG laser capsulotomy for posterior capsule opacification (PCO), providing evidence-based theoretical support for resolving controversies in postoperative macular edema.

The study protocol was prospectively registered with PROSPERO (CRD420261390298). Systematic searches of PubMed, Embase, Web of Science, Scopus, Ovid Medline, and Cochrane Library were conducted from inception through May 1, 2026, following PRISMA and MOOSE guidelines. Studies were selected based on the PICOS framework: patients with posterior capsule opacification receiving Nd: YAG capsulotomy, comparing baseline and postoperative CMT. Exclusion criteria encompassed animal studies, secondary literature, non-English publications, and studies lacking CMT data. A total of 3 RCTs and 20 cohort studies met the eligibility criteria. Primary outcomes were CMT changes at postoperative day 1, week 1, month 1, and month 3. Risk of bias was assessed using Cochrane RoB 2.0 and Newcastle-Ottawa Scale. Meta-analyses were performed using Review Manager 5.4.1 and Stata 16.0, applying fixed effects or random-effects models based on heterogeneity (I ²), with publication bias evaluated via Egger's test and funnel plots. Additional analyses included meta-regression (ethnicity, study design, sample size, steroid use) and subgroup analyses (laser energy, capsulotomy size, OCT devices, baseline BCVA).

Analysis of 23 studies (1,762 eyes) demonstrated significant CMT increase at postoperative week 1 (MD: 8.72 μm; p < 0.001; I ² = 85%), month 1 (MD: 3.69 μm; p < 0.001; I ² = 12%), month 3 (MD: 5.07 μm; p < 0.001; I ² = 0%), with no change at day 1 (MD: 0.06 μm; p = 0.97; I ² = 0%). At week 1, greater CMT change occurred with laser energy ≥ 50 mJ and baseline BCVA ≥ 0.5 logMAR. Meta-regression showed no significant associations for ethnicity (p = 0.06), study design (p = 0.63), steroid use (p = 0.83), or sample size (p = 0.23). The overall risk of bias was considered moderate, while no significant publication bias was identified.

This meta-analysis suggested a possible temporal pattern of CMT increases following Nd: YAG laser capsulotomy, with changes observed from week 1 through month 3 but not clearly at day 1. Subgroup analyses prompted by heterogeneity at week 1 indicated that higher energy levels and poorer baseline vision might be associated with greater thickness changes, while meta-regression did not show consistent associations with ethnicity, study design, steroid use, or sample size.