Method and apparatus for aligning a mask with the visual axis of an eye

Abstract

A method is provided for increasing the depth of focus of an eye of a patient. A visual axis of the eye is aligned with an instrument axis of an ophthalmic instrument. The ophthalmic instrument has an aperture through which the patient may look along the instrument axis. A first reference target is imaged on the instrument axis at a first distance with respect to the eye. A second reference target is imaged on the instrument axis with the ophthalmic instrument at a second distance with respect to the eye. The second distance is greater than the first distance. Movement is provided such that the patient's eye is in a position where the images of the first and second reference targets appear to the patient's eye to be aligned. A mask comprising a pin-hole aperture having a mask axis is aligned with the instrument axis such that the mask axis and the instrument axis are substantially collinear. The mask is applied to the eye of the patient while the alignment of the mask axis and the instrument axis is maintained. Maintaining alignment of the mask axis and the instrument axis may be facilitated by capturing an image of the eye.

Description

RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 10 / 854,032, filed May 26, 2004, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60 / 479,129, filed on Jun. 17, 2003, the entirety of which is hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This application is directed to masks for improving the depth of focus of an eye of a human patient and methods and apparatuses for applying such masks. More particularly, this application is directed to apparatuses and methods for aligning a mask with the line of sight of an eye and applying the mask to the eye. [0004] 2. Description of the Related Art [0005] Presbyopia, or the inability to clearly see objects up close is a common condition that afflicts many adults over the age of 40. Presbyopia diminishes the ability to see or read up close. Near objects appear blurry and out of focus. Presbyopia may be caused by defec...

AI Technical Summary

Benefits of technology

[0009] In one embodiment, a method is provided for increasing the depth of focus of an eye of a patient. The eye has a visual axis. The visual axis of the eye is aligned with an instrument axis of an ophthalmic instrument. The ophthalmic instrument has an aperture through which the patient may look along the instrument axis. A first reference target is imaged on the instrument axis at a first distance with respect to the eye. A second reference target is imaged on the instrument axis at a second distance with respect to the eye. The second distance is greater than the first distance. Movement is provided such that the patient's eye is in a position where the images of the first and second reference targets appear to the patient's eye to be aligned. A mask comprising a pin-hole aperture having a mask axis is aligned with the instrument axis such that the mask axis and the instrument axis are substantially collinear. The mask is applied to the eye of the patient while the alignment of the mask and the instrument axis is maintained.

[0010] In another embodiment, a method for increasing the depth of focus of an eye of a patient is provided. The eye includes a visual axis and a cornea that has an epithelial sheet, a Bowman's membrane, and a stroma. The visual axis of the eye is located using more than one reference target. A mask that includes a pin-hole aperture having a mask axis is aligned with the visual axis of the eye. The mask is applied to the eye while maintaining the alignment of the mask axis and the visual axis.

[0017] In one embodiment, a mask configured to be implanted in a cornea of a patient to increase the depth of focus of the patient includes an anterior surface, a posterior surface, and a plurality of holes. The anterior surface is configured to reside adjacent a first corneal layer. The posterior surface is configured to reside adjacent a second corneal layer. The plurality of holes extends at least partially between the anterior surface and the posterior surface. The plurality of holes is configured to substantially eliminate visible diffraction patterns.

[0018] In another embodiment, a mask configured to be implanted in a cornea of a patient to increase the depth of focus of the patient is provided. The mask includes a body that has an anterior surface configured to reside adjacent a first corneal layer and a posterior surface configured to reside adjacent a second corneal layer. The body is formed of a substantially opaque material that has a relatively high water content. The body is capable of substantially maintaining natural nutrient flow from the first corneal layer to the second corneal layer. The body being is configured to substantially eliminate diffraction patterns that are visible to the patient.

[0019] In another embodiment, a method of making a mask is provided. A body is configured to have an anterior surface capable of residing adjacent a first layer of a cornea of a patient and a posterior surface capable of residing adjacent a second layer of the cornea. A peripheral portion of the body is configured to be substantially opaque to incident light. A central portion of the body is configured to be transparent along an optic axis to substantially all of the incident light. The body is configured with a transport structure capable of substantially maintaining natural nutrient flow from the first layer to the second layer without producing visible diffraction patterns.

Problems solved by technology

Presbyopia may be caused by defects in the focusing elements of the eye or the inability (due to aging) of the ciliary muscles to contract and relax and thereby control the shape of the lens in the eye.

However, if the cornea or the lens are not functioning properly, or are irregularly shaped, the images may not converge at a single point on the retina.

Similarly, the image may not converge at a single point on the retina if the muscles in the eye can no longer adequately control the lens.

However, some vision deficiencies, such as presbyopia, are not adequately addressed by these approaches.

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