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Discovery diagnostic instrument (DDI): a combination aberration corneal topographer auto refractor for contact lens cataract and refractive surgery

Poster Details

First Author: S.El Hage USA

Co Author(s):    E. Sarver   D. Sanders           

Abstract Details


To develop a fast and easy to use combination corneal topographer / ocular aberrations system to support contact lens, cataract and refractive surgery.


Research setup


We combined a reflective ring target for corneal topography with a Hartmann screen sensor for ocular aberrations measurement into a single instrument. Both corneal topography and ocular aberration measurements are acquired simultaneously along the same optical axis. Two illumination sources, one invisible to the eye and the other white light, are used for the ring target. This allows measurements under scotopic to photopic conditions for both corneal topography and ocular aberrations. Automatic acquisition is used to simplify and speed up taking an exam. Iris registration is used to ensure accurate comparison of corneal or ocular astigmatism calculations over time or pre- and post-operatively.


The combination unit can automatically acquire corneal topography and ocular aberration exams in less than 30 seconds. Using fixed targets, the iris registration feature was shown to be able to detect rotations as small as one degree providing accurate comparison of astigmatism axis between exams for either corneal topography or ocular aberrations. The combination of corneal aberrations and ocular aberrations permits calculation of internal aberrations to evaluate the success of a toric contact lens, phakic or aphakic IOL. In addition, the corneal aberrations provide the information used to select the appropriate aspheric IOL to balance corneal spherical aberrations. Post-op evaluation can verify the degree of success of the aspheric IOL.


The resulting combination instrument has advanced features that make it fast and easy to use and is particularly useful for the contact lens, cataract and refractive surgeon. FINANCIAL DISCLOSURE?: No

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