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Design Principles and Limitations of Wave-Front Guided Contact Lenses

Thibos, Larry N. Ph.D.; Cheng, Xu; Bradley, Arthur

Eye & Contact Lens: Science & Clinical Practice: January 2003 - Volume 29 - Issue 1 - p S167-S170
CONTENTS: SESSION VII: HOW CAN WE IMPROVE THE VISUAL RESULTS OF CONTACT LENS WEAR?
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The concept of the wave-front guided design of contact lenses is presented from three vantage points: ray optics, wave front aberrations, and optical path-length errors. We argue that the goal of contact lenses is to make all of the optical paths from a distant object to the retina equal in length, regardless of where the path intersects the plane of the eye’s pupil. The aberration map of an eye is a prescription for such a lens. Unfortunately, variability of measured aberration maps is a fundamental limit to our knowledge of the true aberration structure of an eye. Variability arises because the eye is a biologic system that changes over time for normal, physiologic reasons. Furthermore, uncertainty in our measurement of the aberration map because of such variable factors, such as alignment of the aberrometer to the eye by the clinician or small fixation errors committed by the patient, will make it difficult to achieve a full measure of success with aberration-correcting contact lenses. The clinical implication of these findings is that multiple measurements of the aberration map should be collected using a protocol that includes realignment of the instrument and then averaging the aberration maps to reduce the level of uncertainty associated with any single measurement.

From the School of Optometry, Indiana University, Bloomington, IN.

Address correspondence to: Larry N. Thibos, School of Optometry, Indiana University, Bloomington, IN 47405. Phone: (812) 855-9842; fax: (812) 855-7045; e-mail: thibos@indiana.edu.

Accepted September 24, 2002.

This study was supported by NEI grant R01-EY05109.

© 2003 Lippincott Williams & Wilkins, Inc.