Anterior Segment OCT Thickness Difference Maps for Monitoring Corneal Thickness Changes: Small-Incision Lenticule...

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• Accurate quantification of corneal changes is crucial for refractive surgery outcomes.
• Small-incision lenticule extraction (SMILE) requires precise measurement of lenticule thickness.
• Current methods for measuring lenticule thickness may have limitations in precision.

Purpose of the Study:

• To develop and validate a self-reconstructed anterior segment optical coherence tomography (AS-OCT) thickness difference map.
• To precisely quantify corneal changes using lenticule thickness in SMILE as a model.
• To compare the accuracy of the novel AS-OCT method with existing tomography techniques.

Main Methods:

• Retrospective study of 22 patients (44 eyes) who underwent SMILE.
• Reconstruction of corneal and stromal thickness difference maps from AS-OCT data using an R software script.
• Comparison of estimated lenticule thickness (ELT) from AS-OCT with planned lenticule thickness (PLT) and Pentacam Scheimpflug tomography measurements.

Main Results:

• The self-reconstructed AS-OCT thickness difference maps (corneal and stromal) showed smaller discrepancies with PLT compared to Pentacam measurements.
• The stromal thickness difference map (STDM) demonstrated a strong correlation with PLT (R² = 0.88).
• The AS-OCT method outperformed Scheimpflug tomography in precision for measuring lenticule thickness.

Conclusions:

• The self-reconstructed AS-OCT thickness difference map accurately measures ELT after SMILE.
• This technique provides superior precision and reliable monitoring of corneal thickness changes compared to Scheimpflug tomography.
• The method enables accurate, layer-specific corneal thickness monitoring for surgical planning and assessment of corneal conditions.