Differences in the corneal biomechanical changes after SMILE and LASIK

Area of Science:

• Ophthalmology
• Corneal Surgery
• Biomechanical Analysis

Background:

• Refractive surgery aims to correct vision by reshaping the cornea.
• Small Incision Lenticule Extraction (SMILE) and Femtosecond Laser-Assisted In Situ Keratomileusis (LASIK) are popular laser vision correction procedures.
• Understanding the biomechanical changes induced by these procedures is crucial for patient safety and outcomes.

Purpose of the Study:

• To compare the effects of SMILE and LASIK on corneal biomechanical properties.
• To evaluate these changes in different levels of myopia.
• To utilize the Ocular Response Analyzer for precise measurements.

Main Methods:

• 187 eyes (SMILE) and 79 eyes (LASIK) were analyzed.
• Patients were grouped by surgery type and myopia severity (≤ -6.00 D or > -6.00 D).
• Corneal hysteresis, corneal resistance factor, and waveform parameters were measured preoperatively and postoperatively.

Main Results:

• Both SMILE and LASIK caused significant decreases in corneal hysteresis and resistance factor.
• In low myopia (≤ -6.00 D), no significant differences were observed between SMILE and LASIK.
• In high myopia (> -6.00 D), LASIK resulted in a significantly greater decrease in corneal hysteresis and resistance factor compared to SMILE.

Conclusions:

• SMILE demonstrates a less pronounced impact on corneal biomechanical properties, specifically hysteresis and resistance factor, in patients with high myopia compared to LASIK.
• These findings suggest potential advantages for SMILE in preserving corneal integrity in higher myopic corrections.