Maximum permissible torsional misalignment in aberration-sensing and wavefront-guided corneal ablation.

Bueeler M; Mrochen M; Seiler T

doi:10.1016/S0886-3350(03)00645-X

Back

Journal article

Maximum permissible torsional misalignment in aberration-sensing and wavefront-guided corneal ablation.

Bueeler M Swiss Federal Institute of Technology Zurich, Institute of Biomedical Engineering, Zurich, Switzerland.
Mrochen M
Seiler T

2004-02-18

Published in:

Journal of cataract and refractive surgery. - 2004

Refractive Surgical Procedures

English PURPOSE
To determine the maximum permissible torsional misalignment in wavefront-guided refractive surgery.

SETTING
University of Zurich, Department of Ophthalmology, Zurich, Switzerland.

METHODS
The effect of torsionally misaligned ablations on the optical outcome was simulated using measured wavefront aberration patterns (2nd to 6th orders) in 130 normally aberrated eyes. The calculations were done for 3.0 mm, 5.0 mm, and 7.0 mm pupils. The optical quality of the simulated correction was rated by the root-mean-square residual wavefront error.

RESULTS
The required accuracy of torsional alignment is higher for the correction of higher-order aberrations than for cylindrical treatments only. To improve the optical performance to the level of the best 10% of a normal, untreated population, ablation would have to occur within a tolerance range of 4.0 degrees for 7.0 mm pupils.

CONCLUSIONS
The tolerance range for torisional alignment in wavefront-guided higher-order corrections depends on the amount of original optical error in each eye. Rough centration based on the surgeon's judgment may not be accurate enough to achieve significantly improved optical quality in a high percentage of treated eyes.

Language