Internal Aberrometry And Dysfunctional Lens Index As Objective Metrics For Posterior Capsular Opacification: A Comprehensive Pre- And Post-Nd:Yag Laser Capsulotomy Study

Posterior capsular opacification (PCO) is the most common long-term complication of cataract surgery and currently lacks an objective grading standard. This study aimed to evaluate DLI, wavefront HOA, and MTF — obtained via internal aberrometry — as objective, quantifiable metrics for PCO assessment and post-capsulotomy treatment response monitoring.

Study was conducted at Anterior Segment Clinic of Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey.

This prospective study included 47 eyes of 39 patients (25 female, 14 male; mean age 64.0±14.6 years, range 18–92) with visually significant PCO confirmed by slit-lamp biomicroscopy. Eyes with macular/retinal pathology, glaucoma, or corneal opacities were excluded. BCVA (LogMAR), DLI, total and internal HOA (RMS, μm), Zernike aberration components (coma, trefoil, spherical aberration, 5th-order), and MTF at 5–30 cycles/degree were recorded with the iTrace® ray-tracing aberrometer (Tracey Technologies, USA) before and 4 weeks after Nd:YAG laser capsulotomy. The Shapiro–Wilk test assessed normality; Wilcoxon signed-rank test and Spearman's correlation were applied as appropriate (IBM SPSS v27, p<0.05).

All optical quality metrics improved significantly following Nd:YAG capsulotomy (all p<0.001). BCVA improved from 0.52 to 0.10 LogMAR, DLI from 3.10 to 7.25 (0–10 scale), total HOA by 64.5% (0.375±0.269 to 0.133±0.069 μm RMS), and internal HOA by 66.9%. Internal coma, spherical aberrations were significantly reduced (all p<0.001), whereas trefoil remained unchanged (p=0.49), consistent with a lens-specific origin of PCO-induced aberrations. MTF improved across multiple spatial frequencies (p<0.05). Pre-operatively, DLI correlated strongly with internal HOA (r=−0.946) and total HOA (r=−0.937; both p<0.001), but not with BCVA or MTF. Post-operatively, DLI correlated with both MTF (r=+0.715) and internal HOA (r=−0.769; both p<0.001).

PCO grading remains one of the few areas in ophthalmology still reliant on subjective assessment — at a time when objective classification systems are becoming standard across medicine. DLI correlated strongly with internal HOA pre- and post-capsulotomy (r=−0.946, r=−0.769), converged with MTF post-operatively, and outperformed BCVA in reflecting the true optical burden of PCO. The lens-specific Zernike profile confirms DLI captures a biologically meaningful signal unique to PCO. These findings position DLI as an objective, standardizable biomarker for PCO grading — bringing the same rigor to PCO classification that wavefront analysis brought to refractive surgery. Validation in larger multicenter studies is the necessary next step.