Method and apparatus for alignment of intracorneal inlay

Abstract

A method of correcting refractive error in an eye, comprising the steps of marking at least one axis on the surface of the cornea. A portion of the cornea is then separated, forming a first anterior facing surface and a second posterior facing surface. An inlay having at least one axis indicated on the surface thereof is positioned between the first and second surfaces, and the at least one axis on the inlay is aligned with the at least one axis on the surface of the cornea. This results in precise positioning and orientation of the inlay and thus correction of astigmatic error in the cornea.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method and apparatus for correcting the astigmatic refractive, error in the cornea of the eye. In particular, the cornea is modified by forming a flap in the cornea and exposing a portion of the cornea underlying the flap. The exposed portion is marked and an asymmetric inlay having a thin removable, transparent sheet with markings indicated thereon is positioned on the exposed portion of the cornea. The markings on the cornea and those on the sheet are aligned to ensure proper positioning of the asymmetric inlay. BACKGROUND OF THE INVENTION [0002] A normal emetropic eye includes a cornea, a lens and a retina. The cornea and lens of a normal eye cooperatively focus light entering the eye from a far point, i.e., infinity, onto the retina. However, an eye can have a disorder known as ametropia, which is the inability of the lens and cornea to focus the far point correctly on the retina Typical types of ametropia are myop...

AI Technical Summary

Benefits of technology

[0020] Yet another object of the present invention is to provide a method for adjusting the shape of a live cornea to correct astigmatic conditions by aligning the inlay with markings on the cornea.

[0025] The foregoing objects are further attained by an inlay for correcting the refractive error in the cornea of the eye, comprising a first surface for placement onto an exposed surface of the cornea, a second surface opposite the first surface, and a removable sheet of material overlying the second surface, the sheet having markings thereon for accurately positioning the inlay on the exposed surface of the cornea

Problems solved by technology

Therefore, an astigmatic eye is incapable of sharply focusing images on the retina.

Although these optical methods can be used to correct vision in eyes suffering from low myopia, or in eyes suffering from hypermetropic, hyperopic or astigmatic conditions which are not very severe, these methods are ineffective in correcting vision in eyes suffering from severe forms of ametropia.

Altering the shape of the cut portion of the cornea changes the refractive power of this cut portion, which thus affects the location at which light entering the cut portion of the cornea is focused.

However, the technique is impractical because it employs very complicated and time consuming freezing, cutting and thawing processes.

However, the conventional lenses and methods for type of correction are often impractical for correcting astigmatic error in the eye.

Often is difficult to properly position and maintain the lens in the correct orientation relative to the cornea, thereby making the procedure difficult and time consuming.

However, because only a certain amount of cornea can be ablated without the remaining cornea becoming unstable or experiencing outward bulging (eklasia), this technique is not especially effective in correcting very high myopia or large astigmatic error.

Hence, this method typically cannot be effectively used to correct high myopia or large astigmatic error, because, in order to reshape the cornea to the degree necessary to alter its refractive power to sufficiently correct the focusing of the eye, too much of the cornea would need to be ablated.

However, these techniques generally only have a mark or multiple marks on a portion of the lens.

The conventional procedures do not allow the proper alignment of the cornea surface and the lens implanted thereon.

Therefore, existing procedures are inadequate to correct astigmatic error.

Furthermore, many of these procedures have permanent markings on the lens, which may hinder the sight of the patient.

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