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

1. An apparatus for aligning a mask with a visual axis of an eye of a patient, the apparatus comprising:

a first target positioned on an instrument axis at a first distance relative to a first location;

a second target positioned on the instrument axis at a second distance relative to the first location; and

a marker configured to indicate the location of the instrument axis;

wherein the mask comprises an aperture having a mask axis that can be positioned substantially collinear with the instrument axis, further wherein the mask comprises an annulus configured to be substantially opaque to visible light and to extend between the aperture and an outer periphery of the mask, the annulus having an inner peripheral region between a central region and the aperture and an outer peripheral region between the central region and the outer periphery of the mask, the inner peripheral, central and outer peripheral regions each having a nutrient transport structure for conveying nutrients between anterior and posterior surfaces of the mask, the nutrient transport structure providing an amount of open area per unit area in the central region that is greater than an amount of open area per unit area in at least one of the outer peripheral region and the inner peripheral region.

2. The apparatus of claim 1 , wherein the marker comprises an image capture device and a display device, the display device being configured to reproduce an image of the eye taken by the image capture device.

3. The apparatus of claim 2 , wherein the patient actuates a trigger when the patient's eye is aligned with the instrument axis.

4. The apparatus of claim 3 , wherein the image capture device further compares a real-time position of the patient's eye with the image of the eye captured when the patient actuates the trigger.

5. The apparatus of claim 2 , wherein the apparatus is configured to track movements of the patient's eye during a procedure.

6. The apparatus of claim 5 , wherein the apparatus comprises a display device and is configured to display a reference and to move the reference in a manner corresponding to movements of the eye such that a real-time position of the visual axis may be tracked.

7. The apparatus of claim 6 , wherein the reference comprises a ring that can be overlaid upon on image of the patient's eye such that the position of the ring and the position of the eye may be simultaneously visible to a user.

8. The apparatus of claim 1 , wherein the marker comprises a light source and a marking target, the light source configured to project an image of the marking target onto the eye.

9. The apparatus of claim 1 , further comprising a fixture for locating the eye at the first location.

10. The apparatus of claim 1 , further comprising a beamsplitter positioned on the instrument axis to intercept light from the marker and direct the light toward a fixture for positioning the patient relative to the apparatus.

11. The apparatus of claim 1 , further comprising a mirror configured to be moved into position on the instrument axis to intercept light from the marker and direct the light toward a fixture for positioning the patient relative to the apparatus.

12. The apparatus of claim 1 , further comprising a lens optically coupled with the first and second targets, the second distance being equal to the focal length of the lens, whereby the second target is imaged at approximately infinity.

13. The apparatus of claim 1 , wherein the first distance is less than the second distance.

14. The apparatus of claim 1 , wherein the amount of open area per unit area in the central region is greater than the amount of open area per unit area in the outer peripheral region.

15. The apparatus of claim 1 , wherein the amount of open area per unit area in the central region is greater than the amount of open area per unit area in the inner peripheral region.

16. The apparatus of claim 1 , wherein the nutrient transport structure has larger nutrient flow paths in the center region than in at least one of the outer peripheral region and the inner peripheral region.

17. An apparatus for aligning an implant with a visual axis of an eye of a patient, the apparatus comprising:

an instrument having an instrument axis and an aperture through which the patient may look along the instrument axis; and

wherein the implant comprises an aperture having an implant axis that can be positioned substantially collinear with the instrument axis, the implant further comprising a annulus configured to be substantially opaque to visible light and to extend between the aperture and an outer periphery of the implant, the annulus having an inner peripheral region between a central region and the aperture and an outer peripheral region between the central region and the outer periphery of the implant, the inner peripheral, central and outer peripheral regions each having a nutrient transport structure for conveying nutrients between anterior and posterior surfaces of the implant, the nutrient transport structure providing a concentration of open area in the central region that is greater than a concentration of open area in at least one of the outer peripheral region and the inner peripheral region.

18. An apparatus for aligning a corneal implant with a visual axis of an eye of a patient, the apparatus comprising:

an instrument having an instrument axis and an aperture through which the patient may look along the instrument axis; and

wherein the corneal implant comprises an aperture having a corneal implant axis that can be positioned substantially collinear with the instrument axis, the corneal implant further comprising a annulus configured to be substantially opaque to visible light and to extend between the aperture and an outer periphery of the corneal implant, the annulus having an inner peripheral region between a central region and the aperture and an outer peripheral region between the central region and the outer periphery of the corneal implant, the inner peripheral, central and outer peripheral regions each having a nutrient transport structure for conveying nutrients between anterior and posterior surfaces of the corneal implant, the nutrient transport structure providing a concentration of open area in the central region that is greater than a concentration of open area in at least one of the outer peripheral region and the inner peripheral region.