The Impact of Soft Contact Lenses on the Corneal Neuromediators and Optical Quality in High Myopia Prior to SMILE

This study included 160 eyes from high myopia patients who underwent Small Incision Lenticule Extraction. Patients were devided into three groups based on duration of wearing SCLs: > 10 years group, ≤ 10 years group, and NW group (not SCLs). Corneal higher-order aberrations and densitometry were evaluated using a Pentacam system. Neuromediator levels in corneal stromal lenticules were analyzed using ELISA and immunofluorescence

• This study does not involve any interventions (Other): This study does not involve any interventions

Primary outcomes

• Corneal stromal lenticule Neuromediators [baseline]: Corneal neuromediators, including NGF(pg/mL), CGRP(pg/mL), SP(pg/mL), IGFBP-1(ng/mL), and MANF(pg/mL), which play pivotal roles in maintaining normal physiological functions of the cornea.

Secondary outcomes

• Corneal Aberration [baseline]: Preoperative corneal aberration measurements were performed using a Scheimpflug tomography system (Pentacam; Oculus GmbH, Wetzlar, Germany). Images of the highest quality (designated as OK) were selected for analysis. The coefficients for a standardized diameter of 8 ?mm were examined, followed by an assessment of the clinical significance of total higher-order aberrations (HOA, mm), spherical aberration (Z4, 0, mm), horizontal coma (Z3, 1, mm), vertical coma (Z3, -1, mm), horizontal trefoil (Z3, 3, mm), and oblique trefoil (Z3, -3, mm) in relation to visual quality.
• Corneal Densitometry [baseline]: The Pentacam HR was used to collect data on corneal densitometry values, which were expressed in grayscale units (GSUs), playing a crucial role in quantifying corneal clarity by monitoring transient haze-like reactions. The cornea was divided into four annular zones (0-2 mm, 2-6 mm, 6-10 mm, and 10-12 mm), each exhibiting distinct corneal densitometry values. Based on the anatomical layers of the cornea at different depths, it consists of four layers: a superficial anterior layer of 120 μm, a posterior layer located within the innermost part of the cornea measuring 60 μm; central layers calculated by subtracting thickness of the anterior and posterior layers from the total layer thickness; and a total layer. Corneal densitometry values were measured in the 0-2 mm and 2-6 mm to correspond to the corneal optical zone diameter of SMILE.

Sex: All, ages: 18 Years to 45 Years, accepts healthy volunteers

Inclusion Criteria:

* age ≥ 18 years with stable refraction for at least two years;
* spherical equivalent (SE) < -6.00 D;
* corrected distance visual acuity of 20/20 or better;
* no history of using rigid gas permeable lenses or orthokeratology (OK) lenses prior to examination

Exclusion Criteria:

\- a history of moderate to severe dry eye as well as any ocular or systemic disease that would contraindicate laser refractive surgery.