Higher order aberrations with aspheric ablations using the Nidek EC-5000 CX II laser.
OBJECTIVE
To analyze the change in higher order aberrations in myopic and myopic astigmatic eyes following an aspheric ablation profile for laser in situ keratomileusis (LASIK) using a Nidek EC-5000 CX II excimer laser system.


METHODS
We performed a retrospective audit of 38 eyes (19 patients) with myopia and myopic astigmatism. A customized aspheric transition zone profile (CATz) was used in all eyes (profile 4) with an ablation zone of 5 mm and a transition zone of 9 mm using FinalFit software and a Nidek EC-5000 CX II excimer laser system.


RESULTS
Mean higher order aberrations (RMS) increased from 0.42 microm at baseline to 0.57 microm at 6-month follow-up. Mean spherical aberrations (Z12) increased from 0.02 microm at baseline to 0.33 microm after LASIK. Mean spherical aberration defocus equivalent (DEQ) increased from 0.56 microm at baseline to 1.54 at 6 months after surgery. Mean trefoil (Z6) was -0.11 microm at baseline and -0.14 microm at the 3-month examination. Mean coma (Z7) was -0.09 microm at baseline and -0.10 microm after surgery. Mean coma (Z8) was -0.03 at baseline and 0 at the 3-month examination. Mean trefoil (Z9) was -0.03 at baseline and -0.12 at the 3-month examination.


CONCLUSIONS
The amount of postoperative higher order aberrations in these myopic eyes was acceptable. However, the clinical significance of these numerical changes in aberrations is not known.
Yeung
Ian Y L
IY
Midland Eye Institute, West Midlands, United Kingdom.
Mantry
Sanjay
S
Cunliffe
Ian A
IA
Benson
Mark T
MT
Shah
Sunil
S
D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000601:surgery*; D019781:Corneal Topography; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis; D012029:Refraction, Ocular; D012189:Retrospective Studies; D014792:Visual Acuity