Quantitative Comparison of Clear Corneal Incisions: Femtosecond Cataract Laser Versus Manual Keratome Using Anterior Segment Optical Coherence Tomography
Narrative Responses:
Purpose
To compare the morphology of clear corneal incisions (CCI) created during cataract surgery with a Femtosecond Laser (FS) (Catalys, Optimedica) versus those created using a 2.65mm steel keratome using Anterior Segment Optical Coherence Tomography (AS-OCT, Spectralis, Heidelberg) and also to analyze the intended versus the achieved morphological characteristics of FS created CCI's.
Methods
Using Image J software (NIH, Bethesda, MD), CCI morphology on AS-OCT was analyzed one-month following cataract surgery in 20 FS and 15 age matched keratome eyes. CCI length, endothelial gaping (EG), endothelial misalignment (EM) and rate of descemet’s membrane detachment (DMD) were compared among the two groups. In addition, CCI length, posterior plane depth (depth) and posterior side cut angle (angle) were analyzed using AS-OCT in 20 FS eyes one-month following surgery and compared to the programmed laser parameters.
Results
Mean CCI length was 1.994±0.071 vs. 2.041±0.231 mm (p=0.39), EG was 0.144±0.03 vs. 0.194±0.093 mm (p=0.03) and EM was 0.041±0.03 vs. 0.075±0.056 mm (p=0.022) in the FS and keratome groups respectively. 0/20 FS eyes had a DMD compared to 3/16 keratome eyes (p=0.04). 6/20 FS eyes had visible posterior wound retraction compared to 11/16 of the keratome eyes (p=0.02). Mean CCI length was 1.994±0.071 mm (94.9% of intended 2.1mm), posterior plane depth was 65.3±0.7% (93.3% of intended 70%), and posterior side cut angle was 41.3 ± 0.95 degrees (91.7% of intended 45 degrees).
Conclusion
CCI created using FS had significantly lower EG, EM and DMD compared to those created using a keratome. FS created CCI were within 10% of the intended measurements for length, depth and angle one-month following surgery.