Excellent outcomes have been reported1 in terms of safety, efficacy, and predictability with the iLASIK Suite (Abbott Medical Optics Inc., Santa Ana, California). This system combines wavefront-guided ablations delivered by the CustomVue system (Abbott Medical Optics Inc.) with the benefits of femtosecond- laser–made corneal flaps. These flaps are created using the IntraLase iFS (Abbott Medical Optics Inc.).
Two groups, one in the United States and one in Europe, recently evaluated the iLASIK Suite to determine its benefits in the clinical setting. In the US multicenter study,1 131 patients at eight centers were evaluated. All patients were at least 21 years of age and had 20/20 or better BCVA in each eye. Preoperative manifest refractive error was between -0.50 and -6.00 D, with a cylinder component up to -3.00 D and a maximum manifest refraction spherical equivalent of -6.00 D. Postoperative data including BCVA, UCVA, pupillometry, aberrometry, and contrast sensitivity were recorded at 1- and 3-month follow-up.
Patients were asked to fill out a satisfaction questionnaire at each follow-up visit. At 3 months, investigators reported that 67.9% of eyes had 20/16 or better UCVA; 96.7% of eyes had 20/20 or better UCVA, and 100% achieved 20/25 UCVA or better. No retreatments were needed, and all patients reported that they were either very satisfied or satisfied with their vision after surgery.
I am participating in the European multicenter iLASIK study to verify these results in a different geographic and cultural setting. Participating LASIK centers include practices in Spain, France, Germany, and Italy. Inclusion criteria, data collection, and analysis protocols mirror those used in the US study. At Vissum Ophthalmology Clinic in Seville, Spain, we have completed enrollment of our patient cohort. A total of 50 eyes (25 patients) have been treated at Vissum and have 3-month follow-up data available.
Our results are similar to those reported by our American colleagues, with 77% of eyes achieving 20/16 or better UCVA at 3 months (Figures 1 and 2). Additionally, 90% had 20/20 UCVA and 100% had 20/25 UCVA at 3 months. One eye required enhancement due to undercorrection, and all patients stated that they were satisfied or very satisfied with their vision after surgery.
IMPROVEMENT ON CONVENTIONAL LASIK
The iLASIK Suite is an improvement on conventional LASIK for several reasons. First, the femtosecond laser produces better optical quality because it creates planar flaps that do not induce optical aberrations. Second, the femtosecond laser produces a smoother stromal bed; this is key when performing customized ablation. Third, the femtosecond laser can create safer, more reproducible, and thinner flaps compared with conventional microkeratomes, eliminating intraoperative complications such as buttonholes and incomplete or irregular flaps. Fourth, wavefront-guided ablations with this system not only address lower- and higherorder aberrations (HOAs) but also compensate for cyclotorsion and pupil centroid shift with iris registration technology. This is especially important when treating patients with high astigmatism.
One feature that may make this technology superior to other wavefront-guided platforms is that the WaveScan aberrometer incorporates Fourier analysis. This algorithm allows more accurate reconstruction of the wavefront, because it uses all available Hartmann-Shack data points from any pupil shape up to 7 mm, even in elliptical pupils. When the WaveScan aberrometer is used, we have noticed a more precise and customized ablation pattern compared with Zernike polynomials.
The combination of wavefront-guided ablations and femtosecond laser flaps with the iLASIK Suite compares favorably to conventional LASIK with mechanical microkeratomes in terms of quality of vision under scotopic conditions. Schallhorn et al2 compared the two techniques using a night-driving simulator and found the quality of vision in dim light conditions, and therefore the ability to detect road hazards when driving at night, was worse in the conventional LASIK group. The iLASIK group had significantly improved mean night-driving visual performance.
Holladay3 reported better results using wavefrontguided treatments with femtosecond laser flap creation when compared with wavefront-optimized treatments with femtosecond laser flap creation. His study found that, in 88% of patients in the wavefront-guided group, the level of HOAs was the same (76%) or had improved (12%) after surgery. With wavefront-optimized treatments, HOAs were worse in 41% of patients, the same in 51%, and better in 8%.
Liu4 conducted a 90-eye contralateral study comparing iLASIK with wavefront-optimized treatments plus femtosecond laser flap creation. At 1 week, 91% of eyes in the iLASIK group had UCVA of 20/20 or better versus 78% in the wavefront-optimized group. At 3 months, 85% of eyes had 20/16 or better UCVA and 70% had 20/12 or better in the iLASIK group compared with 80% and 50%, respectively, in the wavefrontoptimized group. A statistically significantly greater increase in postoperative HOAs and statistically significantly more residual cylinder were seen in wavefrontoptimized eyes.
Antonio Uceda-Montanes, MD, is the Medical Director of Vissum Clinica Oftalmologica, Seville, Spain. Dr. Uceda- Montanes states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +34 954933933; fax: +34 954933930; e-mail: firstname.lastname@example.org.
- Trattler WB.Refractive outcomes with advanced wavefront-guided LASIK.Paper presented at:the American Society of Cataract and Refractive Surgery meeting;April 9-14,2010;Boston.
- Schallhorn SC,Tanzer DJ,Kaupp SE,Brown M,Malady SE.Comparison of night driving performance after wavefront- guided and conventional LASIK for moderate myopia.Ophthalmology.2009;116(4):702-709.
- Holladay JT.Wavefront-guided ablation vs wavefront-optimized ablation.Paper presented at:The World Ophthalmology Congress;June 28,2008;Hong Kong.
- Liu A.Prospective randomized eye-to-eye comparison of hyperopic wavefront-guided LASIK and hyperopic wavefront- optimized LASIK.Paper presented at:the American Society of Cataract and Refractive Surgery meeting;April 11,2010;Boston.