Corneal Remodeling After Myopic SMILE: An Optical Coherence Tomography and In Vivo Confocal Microscopy Study

Area of Science:

• Ophthalmology
• Refractive Surgery
• Corneal Science

Background:

• Small incision lenticule extraction (SMILE) is a popular refractive surgery for myopia.
• Understanding corneal remodeling post-SMILE is crucial for refractive outcome prediction.
• A 10% overcorrection nomogram is sometimes used to enhance accuracy.

Purpose of the Study:

• To investigate corneal changes, specifically epithelial remodeling and lenticule thickness, in the first six months after SMILE surgery.
• To evaluate the impact of a 10% overcorrection nomogram on refractive outcomes.
• To correlate these changes with the degree of myopia and identify factors influencing refractive accuracy.

Main Methods:

• Prospective observational study of 60 eyes from 30 patients undergoing SMILE for low to moderate myopia.
• Application of a 10% overcorrection nomogram for all participants.
• Utilized spectral-domain optical coherence tomography (SD-OCT) for epithelial and corneal thickness mapping, and in vivo confocal microscopy (IVCM) for stromal interface assessment.

Main Results:

• Mean refractive correction was -3.99 D pre-op and -0.09 D post-op.
• Central epithelial thickness increased significantly (53.7 to 57.1 µm) at 6 months (P < .001).
• Measured lenticule thickness was 16 µm less than programmed (P < .001), correlating with myopia degree.

Conclusions:

• Epithelial thickening and lenticule thickness mismatch led to undercorrection with the 10% overcorrection nomogram.
• Interface fibrosis was not a significant factor in lenticule thickness error.
• Additional overcorrection may be necessary for improved refractive accuracy in SMILE procedures.