Agreement Between Predicted and Actual Measured Ablation Depth After FS-LASIK Using Different Rotating Scheimpflug...

Area of Science:

• Ophthalmology
• Laser Vision Correction
• Corneal Surgery

Background:

• Femtosecond laser-assisted LASIK (FS-LASIK) is a common refractive surgery.
• Accurate prediction of ablation depth (AD) is crucial for successful outcomes.
• Discrepancies between predicted and actual ablation can lead to refractive errors.

Purpose of the Study:

• To compare predicted versus postoperatively measured corneal ablation depth (postop-AD) after FS-LASIK.
• To evaluate accuracy across central, paracentral, and midperipheral corneal locations.
• To assess performance of Scheimpflug analyzers and OCT in predicting AD.

Main Methods:

• Corneal thickness measured pre- and postoperatively (1 and 3 months).
• Predicted AD calculated using ORK-CAM software.
• Comparison of predicted AD with postop-AD using Bland-Altman analysis.

Main Results:

• At 1 month, predicted AD was underestimated centrally/paracentrally and overestimated mid-peripherally by all devices.
• Δ-AD (difference between predicted and postop-AD) approached zero at 3 months.
• Agreement between predicted and postop-AD was moderate, slightly better with RTVue OCT.

Conclusions:

• Predicted AD is underestimated in central/paracentral cornea and overestimated in the mid-periphery after FS-LASIK.
• Findings may help explain and prevent refractive errors post-surgery.
• Device accuracy varies, with RTVue OCT showing slightly better agreement.