Ray-Tracing Aberrometry and the Dysfunctional Lens Index for Objective Assessment of Posterior Capsular Opacification

PURPOSE: To evaluate the dysfunctional lens index (DLI), higher-order aberrations (HOA), and modulation transfer function (MTF) from ray-tracing aberrometry as objective markers of posterior capsular opacification (PCO) and treatment response. SETTING: Two tertiary ophthalmology centers, Istanbul, Turkey. DESIGN: Prospective interventional study with a clear-capsule pseudophakic control group. METHODS: Eyes with visually significant PCO after uncomplicated phacoemulsification with monofocal IOL implantation underwent ray-tracing aberrometry and 4 weeks after Nd:YAG capsulotomy; one eye per patient was analysed. CDVA, DLI, total and internal HOA root mean square (RMS), Zernike components, and MTF at 5-30 cycles/degree (cpd) were compared with clear-capsule control eyes with the same IOL. RESULTS: Thirty-one eyes of 31 patients (mean age 66.7 years; 21 female) and 28 control eyes were included. All parameters improved after capsulotomy (all P<.001): CDVA from 0.52 to 0.10 logMAR, DLI from 3.10 to 7.20, internal HOA RMS by 66.9%. Internal coma and trefoil decreased, whereas spherical aberration was unchanged (negative control). MTF improved at all six spatial frequencies. Pre-operatively, PCO eyes were degraded relative to controls (DLI 3.35 vs 7.67; P<.001); post-operatively they matched controls (7.23 vs 7.67; P=.44). DLI correlated with internal HOA (r=-0.947) and MTF (r=+0.842) but not CDVA (r=-0.051). CONCLUSIONS: Ray-tracing aberrometry offers an objective view of PCO-induced optical degradation. Because the DLI tracks internal aberrations and MTF yet remains independent of high-contrast acuity, it captures impairment that CDVA alone overlooks, and returns to clear-capsule levels after capsulotomy. The DLI thus serves as a useful adjunctive marker for gauging PCO-related degradation and monitoring treatment response.