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David Joseph Slater, Bruno Lay, Christine W Sindt; Using Corneal elevation specific technology to anti-aberrate a contact lens. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1489.
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© 2017 Association for Research in Vision and Ophthalmology.
Zernike polynomial wavefront error can be deconstructed to describe ocular surface elevation and is positively correlated to visual acuity.Actual surface elevation fit error,however,is also strongly positively correlated to visual acuity.The corneal front surface contributes approximately half of the total aberrations of the eye.This amount varies by age,surgical history,and disease.A contact lens placed on the ocular surface to neutralizes the front surface wavefront error.In many cases however posterior corneal changes in elevation contribute to continued decrease in visual acuity.In the past,XYZ rotational instability has prevented placement of higher order optics on contact lenses.We hypothesize elevation specific technology,utilizing an ocular surface impression and registering it with the anterior elevation map of a Schiemflug topography,we could anti aberrate residual back corneal surface derived elevation fit error to improve vision.
Utilizing a low viscosity,addition polymerizing polyvinyl siloxane precision impression material with hydrophilic properties, an impression is obtained of the globe,creating a 1-2 micron accurate representation of the true anterior surface elevation.Lenses designed with elevation specific technology have been shown to be XYZ rotationally stable while on the eye.The true anterior surface elevation was aligned with the schiemflug image of the corneal front surface to register the images.In this manner, the back corneal surface of the schiemflug image was registered to the front surface of the contact lens,aligning the lens optics over the visual axis.The posterior corneal elevation fit error was calculated to anti-aberrate the contact lens front surface.A lens was generated utilizing a data points file, producing a surface defined by elevations,not by symmetrical radius of curvatures.
Posterior elevation fit error was successfully applied to the front surface of an XYZ rotationally stable lens and provided consistent optics.
Visual acuity is determined by aberrations on both the front and back corneal wavefront fit errors.Contact lenses have historically corrected the front surface wavefront error, however residual aberrations have resulted in less than ideal visual quality.Using elevation specific technology to design and register the contact lens on the actual eye,allows the aberrations of the posterior corneal surface to be isolated and corrected.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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