Early results of nidek customized aspheric transition zones (CATz) in laser in situ keratomileusis.
OBJECTIVE
Standard ablation profiles for myopia and myopic astigmatism are spherical in shape and usually induce spherical aberration, often resulting in glare, halo, and other night vision problems. New ablation algorithms with aspheric transition zones may help reduce the amount of induced spherical aberrations in refractive surgery.


METHODS
Between September and November 2002, 52 eyes were treated with bilateral laser in situ keratomileusis (LASIK) using a new ablation profile with customized aspherical transition zone (CATz). Results were analyzed from examinations performed 1 day, 1 and 3 months (if available) after surgery, and compared to a standard LASIK patient group.


RESULTS
Refractive outcome of patients was within +/- 0.50 D of intended correction in 72% on day 1, and 82% at 1 month after surgery. At 1 month after LASIK, mean spherical equivalent refraction was changed from preoperative mean -6.73 +/- 2.04 D to postoperative mean -0.43 +/- 0.80 D (range -2.00 to +1.50 D). No eye lost more than 1 line of visual acuity; 10% gained 1 line and 80% remained unchanged 1 month after surgery. The topographically visible effective optical zone size was larger than in comparable treatments with standard ablation profiles. Spherical aberration was reduced and no patient complained about night vision problems after surgery.


CONCLUSIONS
Customized aspheric transition zones may help reduce induction of spherical aberration in refractive surgical correction of myopia and myopic astigmatism.
Kermani
Omid
O
Augenlaserzentrum Koln, Koln, Germany.
Schmiedt
Karl
K
Oberheide
Uwe
U
Gerten
Georg
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D001251:Astigmatism / Q000601:surgery*; D003319:Corneal Stroma / Q000473:pathology / Q000601:surgery; D019781:Corneal Topography; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011183:Postoperative Complications / Q000517:prevention & control; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity