Abstract
Purpose:
To compare the astigmatic outcomes of laser in situ keratomileusis (LASIK) with flap creation using either a 150kHz or a 60kHz femtosecond laser platform.
Methods:
122 eyes of 61 patients underwent LASIK for compound myopic astigmatism with the Abbott CustomVue S4 excimer laser platform (Abbott Medical Optics, Santa Ana, CA), Flap creation was performed using the Abbott Intralase femtosecond laser platform, and one eye used the Abbott Intralase FS60 60kHz laser, while the contralateral eye used the Intralase iFS 150kHz laser. Preoperative and postoperative assessments were performed and included manifest refraction, vector analysis, topography, and wavefront aberrometry. Eyes were stratified for subgroup analysis based on preoperative manifest astigmatism: 0.25-1, 1.25-2.25, and 2.5-3.5 diopters. Statistics were calculated using t-tests.
Results:
Preoperatively, mean spherical equivalent (SE) was -4.3±2.3 vs -4.3±2.3 diopters(D) (p=0.89), and mean cylindrical error(CE) was 0.6±0.7 vs 0.6±0.4D (p=0.74) in the FS60 60kHz and iFS 150kHz groups, respectively. At postoperative month 12, mean SE was -0.3 ±0.3 vs -0.2±0.3D (p=0.22), and mean CE was 0.1±0.2 vs 0.2±0.2D (p=0.13), respectively.<br /> <br /> Alpins vector analyses for the FS60 60kHz and iFS 150kHz groups, respectively, were: surgically-induced-astigmatism (0.6±0.6 vs 0.6±0.4D, p=0.78), magnitude of error (0.1±0.1 vs 0.1±0.2D, p=0.21), angle of error (7±19° vs 11±23°, p=0.33), correction-index (1±0.3 vs 1±0.3, p=0.67), success-index (0.4±0.9 vs 0.5±1, p=0.45), and flattening-index (0.9±0.3 vs 0.8±0.5, p=0.44).<br /> <br /> Subgroup analysis by preoperative astigmatism showed no significant differences.
Conclusions:
Minimal difference in outcomes between FS60 60kHz and iFS 150kHz platforms based on objective Alpins analysis of astigmatism.