Iris registration in wavefront-guided LASIK to correct mixed astigmatism
Received 27 May 2008; received in revised form 29 September 2008; accepted 25 November 2008.
Purpose
To investigate the predictability, safety, and efficiency of wavefront-guided laser in situ keratomileusis (LASIK) with iris-registration technology to correct mixed astigmatism.
Setting
Vision correction center, Alexandria, Egypt.
Methods
This retrospective double-blind study included randomly selected patients with mixed astigmatism who sought laser refractive surgery. Patients were divided equally into 3 groups and treated with conventional LASIK and manual marking, wavefront-guided LASIK and manual marking, or wavefront-guided LASIK with iris registration (LASIK+IR group). Eyes were analyzed preoperatively and up to 3 months postoperatively.
Results
The LASIK+IR group had better postoperative uncorrected visual acuity (100% 20/30 or better; 90% 20/20 or better; 20% 20/16 or better) than the other groups and did not lose preoperative best spectacle-corrected visual acuity, unlike the other groups. This group also had the highest percentage of eyes that gained lines of acuity (20% 1 line; 10% 2 lines). The LASIK+IR group had the highest predictability of spherical refraction (80% within ±0.50 diopter [D]; 100% within ±1.00 D [P<.05] and the highest predictability of cylinder refraction. The LASIK+IR eyes had a significantly smaller increase postoperatively in coma, trefoil, and secondary astigmatism. There was no significant difference between groups in spherical aberration or quadrafoil. The LASIK-IR group had the most improvement in scotopic contrast sensitivity (P<.05).
Conclusions
Wavefront-guided LASIK with iris registration was more predictable, safe, and efficient than conventional or wavefront-guided LASIK with manual marking in correcting mixed astigmatism. Further studies are needed to confirm these results.
From Tanta University (Khalifa), Tanta, and Alexandria University (El-Kateb, Shaheen), Alexandria, Egypt
Drs. Khalifa and Shaheen are consultants to Schwind Eye-Tech Solutions, Kleinostheim, Germany. Dr. El-Kateb has no financial or proprietary interest in any material or method mentioned.
Supported by Horus Vision Correction Center, Alexandria, Egypt.
ABSTRACT