Purpose: To evaluate postoperative spherical aberration reduction and increase of visual acuity with new Flex Scan and custom ablation software.
Methods: We created a new customized low spherical aberration ablation profile for myopic patients (true spherical ablation). This aspheric algorithm increases ablation in the midperiphery and periphery to reduce surgery-induced spherical aberration. LASIK was performed in 143 eyes, 127 with the true spherical ablation profile, and 16 with the custom true spherical ablation profile. We used the Nidek OPD-Scan and the Nidek EC-5000 excimer laser. Ablation zones of 6.0 to 6.5 mm and transition zones of 8.5 to 9.0 mm were used. Preoperative myopia was as much as -6.50 D, and astigmatism, -2.50 D.
Results: In the true spherical ablation profile group, 37.8% of eyes achieved UCVA better than 1.0 (1.2 to 2.0). In custom true spherical ablation profile eyes, 62.5% achieved UCVA better than 1.0 (1.2 to 1.5). One patient had on the day after surgery (true spherical ablation profile) an UCVA of 3.0 (preoperative UCVA was 0.1 and BSCVA was 1.0 in each eye). Preoperative and postoperative OPD-Scan analysis showed reduction of spherical-like aberrations for dilated pupil after surgery or insignificant changes for most patients. No patient had any complaints concerning quality of vision.
Conclusion: LASIK based on our true spherical ablation profile produced good visual acuity results for myopic patients.