Comparative Evaluation of Higher-Order Aberrations and Corneal Asphericity Between Wavefront-guided and Aspheric LASIK for Myopia

• Published in: Journal of refractive surgery (1995) Vol. 30; no. 11; pp. 777 - 784
• Main Authors: Goyal, Jawahar Lal, Garg, Arushi, Arora, Ritu, Jain, Parul, Goel, Yashpal
• Format: Journal Article
• Language: English
• Published: United States SLACK INCORPORATED 01.11.2014
• Subjects: Ablation; Adult; Astigmatism; Astigmatism - physiopathology; Astigmatism - surgery; Contact lenses; Contrast Sensitivity - physiology; Cornea; Cornea - physiopathology; Corneal Wavefront Aberration - physiopathology; Eye surgery; Female; Humans; Iris; Keratomileusis, Laser In Situ - methods; Lasers; Lasers, Excimer - therapeutic use; Male; Myopia; Myopia - physiopathology; Myopia - surgery; Prospective Studies; Statistical analysis; Topography; Visual acuity; Visual Acuity - physiology; Young Adult; United States > US; Chicago Illinois; India
• ISSN: 1081-597X; 1938-2391
• DOI: 10.3928/1081597X-20141021-10

PURPOSE: To compare visual outcome, higher-order aberrations, and corneal asphericity (Q value) between wavefront-guided and aspheric LASIK for myopia and myopic astigmatism. METHODS: Forty patients were randomly selected to receive wavefront-guided LASIK (wavefront-guided group) or aspheric LASIK (aspheric group) (40 eyes of 20 patients in each group) using the Technolas 217z excimer laser platform (Bausch & Lomb, Rochester, NY). Flaps were created using the Zyoptix XP microkeratome (Bausch & Lomb). Preoperative and postoperative evaluation included uncorrected distance visual acuity (UDVA), corneal topography, wavefront aberrometry, and contrast sensitivity. Minimum follow-up period was 6 months. RESULTS: At 6 months postoperatively, the aspheric group had significantly better UDVA (logMAR 0.04 ± 0.04 [Snellen 20/16] [range: −0.079 to 0.000]) and lower mean residual spherical error (+0.10 ± 0.52 diopters [D] [range: −1.12 to 1.25 D]) than the wavefront-guided group (logMAR UDVA 0.00 ± 0.07 [range: −0.079 to 0.176]; MRSE −0.35 ± 0.47 D [range: −1.5 to 0.62 D]) (At 6 months postoperatively, the aspheric group had significantly better UDVA (logMAR 0.04 ± 0.04 [Snellen 20/16] [range: −0.079 to 0.000]) and lower mean residual spherical error (+0.10 ± 0.52 diopters [D] [range: −1.12 to 1.25 D]) than the wavefront-guided group (logMAR UDVA 0.00 ± 0.07 [range: −0.079 to 0.176]; MRSE −0.35 ± 0.47 D [range: −1.5 to 0.62 D]) ( P = .003 and < .001, respectively). Mean change in higher-order aberration root mean square at 6 months postoperatively (6-mm pupil) was 0.16 ± 0.17 µ m after aspheric LASIK and 0.27 ± 0.28 µ m after wavefront-guided LASIK ( P = .02). Aspheric LASIK induced minimal change in spherical aberrations postoperatively (0.03 ± 0.12 µ m, P = .09), unlike wavefront-guided LASIK (0.23 ± 0.17 µ m, P < .01). Change in Q value was significantly less in the aspheric group (0.53 ± 0.31) than the wavefront-guided group (0.91 ± 0.30) ( P < .01). The aspheric group had significant improvement in contrast sensitivity at all spatial frequencies ( P < .01), whereas the wavefront-guided group showed a slight decrease at higher spatial frequency (18 cycles per degree). CONCLUSIONS: Aspheric LASIK induced significantly less change in higher-order aberrations and maintained corneal asphericity better than wavefront-guided LASIK. The visual outcome and contrast sensitivity was better in the aspheric group at 6 months postoperatively. [[ J Refract Surg . 2014;11(30):777–784.]