Impact Of Preoperative Tear Total Antioxidant Capacity On Refractive Predictability After Keratorefractive Lenticule Extraction
Published 2026 - 44th Congress of the ESCRS
Reference: FP11.02 | Type: Free paper | DOI: 10.82333/nwht-yy52
Authors: Dr Yu-Ting Tsao* 1 , Prof. Chao-Kai Chang 2 , Dr Yi-jen Hsueh 3 , Prof. Hung-Chi Chen 1
1Ophthalmology,Chang Gung Memorial Hospital, Linkou Medical Center,Taoyuan,Taiwan, 2Ophthalmology,Nobel Eye Institute,Taipei,Taiwan, 3Center for Tissue Engineering,Chang Gung Memorial Hospital, Linkou Medical Center,Taoyuan,Taiwan
Purpose
To evaluate the predictive value of preoperative tear total antioxidant capacity (TAC) for refractive outcomes and predictability after keratorefractive lenticule extraction (KLEX).
Setting
A multi-center collaborative study involving clinical sample collection at Nobel Eye Clinic, with laboratory TAC measurements and integrated data analysis performed at the Tissue Engineering Center and the Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, Taiwan.
Methods
This prospective cohort study enrolled 100 eyes of 51 patients undergoing KLEX. Preoperative tear samples were collected using Schirmer strips and analyzed for TAC. Postoperative spherical equivalent (SE) and absolute SE (|SE|) were measured at 1 month. A quadratic regression model was employed to identify the optimal TAC level. Statistical robustness was ensured using bootstrapping (1,000 resamples, 95% BCa CI) and Generalized Estimating Equations (GEE) to adjust for inter-eye correlation and potential covariates, including age, gender, preoperative SE, BCVA, IOP, and tear volume.
Results
Significant positive correlation was observed between preoperative TAC and postoperative SE (r = 0.337, P < 0.001). Furthermore, a quadratic regression model revealed a U-shaped distribution for |SE| (P = 0.042), with the theoretical optimal vertex at 664.8 uM. Eyes within the "homeostatic window" (TAC 300-900 uM) achieved significantly lower |SE| (0.35 ± 0.24 D) compared to the low and high TAC cohorts (P < 0.05). Multivariate GEE analysis confirmed preoperative TAC as an independent predictor of refractive accuracy (P = 0.004).
Conclusions
Preoperative tear TAC serves as a significant biomarker for KLEX outcomes. While a linear correlation exists, the identification of a homeostatic window (300-900 uM) suggests that extremes in TAC levels impair refractive predictability. These findings provide a biological basis for preoperative nomogram adjustments—specifically, targeting over-correction for low TAC and under-correction for high TAC—to enhance surgical precision.