Intraocular Lens Power Calculation after Small Incision Lenticule Extraction

Area of Science:

• Ophthalmology
• Refractive Surgery
• Biomedical Engineering

Background:

• Small Incision Lenticule Extraction (SMILE) is a prevalent refractive procedure.
• Accurate intraocular lens (IOL) power calculation is essential for successful cataract surgery post-SMILE.
• Limited empirical data exists for optimizing IOL power calculations in post-SMILE eyes.

Purpose of the Study:

• To evaluate the accuracy of existing IOL power calculation formulas in eyes that have undergone SMILE.
• To compare formula performance against the gold standard of ray tracing.
• To provide recommendations for IOL power calculation in the post-SMILE population.

Main Methods:

• Retrospective analysis of 88 eyes that had prior SMILE surgery.
• Comparison of multiple IOL power calculation formulas using the ASCRS post-keratorefractive surgery online calculator.
• Ray tracing utilized as the reference standard for refractive prediction.

Main Results:

• The Masket formula exhibited the lowest mean prediction error (-0.36 ± 0.32 D) and median absolute error (0.33 D).
• 70% of eyes achieved refractive outcomes within ±0.50 D using the Masket formula.
• Barrett True K, Barrett True K No History, and Potvin-Hill formulas also demonstrated non-inferior accuracy.

Conclusions:

• The Masket formula is recommended for IOL power calculation in post-SMILE eyes.
• Barrett True K, Barrett True K No History, and Potvin-Hill formulas are viable alternatives.
• Continued research and data collection are needed for empirical optimization of IOL calculations post-SMILE.