# The Relationship Between Concurrent Preoperative Dry Eye Disease and Ascorbic Acid Levels and the Outcomes of Kerato-Lenticule Extraction Surgery

## TL;DR

This study found that patients with dry eye disease and low ascorbic acid levels before surgery had worse vision outcomes after kerato-lenticule extraction.

## Contribution

The study identifies a novel link between preoperative dry eye disease and ascorbic acid levels affecting surgical outcomes in kerato-lenticule extraction.

## Key findings

- The DED-low AA group had worse UDVA one month post-surgery compared to other groups.
- DED-low AA group showed the largest decrease in AA levels after surgery.
- High myopia and large optic zone correlated with worse outcomes in the DED-low AA group.

## Abstract

Purpose: The aim of this study was to investigate the influence of preoperative dry eye disease (DED) and ascorbic acid (AA) status on the outcomes of kerato-lenticule extraction (KLEx) surgery. The postoperative outcomes included visual and refractive parameters.

Method: A prospective, non-randomized controlled trial was conducted, and 68 patients who received KLEx surgery were included. These patients were divided according to their DED status and AA level, and a total number of 33, 19, and 16 patients/eyes were classified into non-DED, DED-high AA, and DED-low AA groups, respectively. The uncorrected distance visual acuity (UDVA), cycloplegia refraction, and AA concentration were determined before and after surgery. The Kruskal-Wallis test was used to investigate the postoperative outcomes among the three groups.

Results: One week postoperatively, the three groups presented similar UDVA and refraction values (all P > 0.05). One month postoperatively, however, the DED-low AA group demonstrated worse UDVA than the non-DED and DED-high AA groups (P = 0.012). After the KLEx surgery, the DED-low AA group still had the lowest AA level compared with the other two groups (both P < 0.05), and the decrease in AA was the largest in the DED-low AA group compared with the other two groups (both P < 0.05). High myopia was related to worse postoperative UDVA in the DED-high AA group (P = 0.034), and high myopia and large optic zone (OZ) were significantly correlated with worse postoperative UDVA in the DED-low AA group (both P < 0.05).

Conclusion: The concurrent presence of DED and a low baseline AA status was correlated with worse postoperative UDVA in patients who received KLEx surgery. Additionally, this population had more risk factors for poor postoperative UDVA than the other populations.