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.

1 . A method of increasing the depth of focus of an eye of a patient, the eye having a cornea and a visual axis, the method comprising: 
 aligning the visual axis with an instrument axis of an ophthalmic instrument, said instrument having an aperture through which the patient may look along the instrument axis, said aligning comprising: 
 imaging a first reference target on the instrument axis at a first distance with respect to the eye;  
 imaging a second reference target on the instrument axis, said second reference target being imaged at a second distance with respect to the patient's eye, the second distance being greater than the first distance; and  
 providing movement of the eye to a position where the images of the first and second reference targets appear to the patient's eye to be aligned;  
   aligning a mask comprising a pin-hole aperture having a mask axis with the instrument axis such that the mask axis is substantially collinear with the instrument axis; and    applying the mask to the eye of the patient while maintaining the alignment of the mask axis and the instrument axis.    
     
     
         2 . The method of  claim 1 , further comprising capturing an image of the eye.  
     
     
         3 . The method of  claim 1 , further comprising generating a visible marker corresponding to the visual axis of the eye.  
     
     
         4 . The method of  claim 3 , wherein the visual marker is projected onto the anterior surface of the eye.  
     
     
         5 . The method of  claim 3 , wherein the visual marker is generated at a display device.  
     
     
         6 . The method of  claim 3 , wherein the visual marker comprises a plurality of visual markers that corresponds to the outer periphery of a mask.  
     
     
         7 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a corneal flap, the corneal flap comprising the outermost 20% of the cornea;    placing the mask on the cornea in a position corresponding to the visual axis; and    placing the hinged corneal flap over the mask.    
     
     
         8 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a corneal flap, the corneal flap comprising the outermost 10% of the cornea;    placing the mask on the cornea in a position corresponding to the visual axis; and    placing the hinged corneal flap over the mask.    
     
     
         9 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a corneal flap, the corneal flap comprising the outermost 5% of the cornea;    placing the mask on the cornea in a position corresponding to the visual axis; and    placing the hinged corneal flap over the mask.    
     
     
         10 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a corneal flap, the corneal flap having a thickness of no more than about 5% of the thickness of the cornea;    placing the mask on the cornea in a position corresponding to the visual axis; and    placing the hinged corneal flap over the mask.    
     
     
         11 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a corneal flap, the corneal flap having a thickness between about 5% and about 10% of the thickness of the cornea;    placing the mask on the cornea in a position corresponding to the visual axis; and    placing the hinged corneal flap over the mask.    
     
     
         12 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a corneal flap, the corneal flap having a thickness between about 5% and about 20% of the thickness of the cornea;    placing the mask on the cornea in a position corresponding to the visual axis; and    placing the hinged corneal flap over the mask.    
     
     
         13 . The method of  claim 7 , further comprising placing a contact lens over a portion of the cornea until an epithelial sheet has adhered to the mask and the stroma.  
     
     
         14 . The method of  claim 1 , wherein applying the mask further comprises: 
 removing an epithelial sheet of the cornea;    creating a depression in the Bowman's membrane at a position corresponding to the visual axis of the eye, the depression being sufficiently deep to expose the stroma and being configured to receive the mask;    placing the mask in the depression such that the mask axis is aligned with the visual axis of the eye; and    placing the removed epithelial sheet over the mask.    
     
     
         15 . The method of  claim 14 , further comprising placing a contact lens over a portion of the cornea until the epithelial sheet has adhered to the mask.  
     
     
         16 . The method of  claim 1 , wherein applying the mask further comprises: 
 applying a first contact lens to the eye; and    placing the mask on the first contact lens such that the mask axis is aligned with the visual axis of the eye.    
     
     
         17 . The method of  claim 16 , further comprising applying a second contact lens over the mask to hold the mask axis in a substantially constant position with respect to the visual axis of the eye.  
     
     
         18 . The method of  claim 1 , wherein applying the mask further comprises: 
 hinging open a portion of the Bowman's membrane;    creating a depression in the top layer of the stroma at a position corresponding to the visual axis of the eye, the depression being configured to receive the mask;    placing the mask in the depression; and    placing the hinged Bowman's membrane over the mask.    
     
     
         19 . The method of  claim 18 , further comprising placing a contact lens over a portion of the cornea until an epithelial sheet has grown over the hinged Bowman's membrane.  
     
     
         20 . The method of  claim 1 , wherein applying the mask further comprises: 
 creating a channel in the top layer of the stroma, the channel being in a plane parallel to the anterior surface of the cornea, the channel being formed in a position corresponding to the visual axis of the eye; and    placing the mask in the channel.    
     
     
         21 . The method of  claim 20 , wherein placing the mask further comprises threading the mask into the channel.  
     
     
         22 . The method of  claim 20 , wherein placing the mask further comprises injecting the mask into the channel.  
     
     
         23 . The method of  claim 1 , wherein applying the mask further comprises: 
 penetrating the top layer of the stroma with an injecting device; and    injecting the mask into the top layer of the stroma with the injecting device at a position corresponding to the visual axis of the eye.    
     
     
         24 . The method of  claim 23 , wherein the injecting device comprises a ring of needles.  
     
     
         25 . The method of  claim 1 , wherein applying the mask further comprises: 
 creating a pocket in the stroma at a position corresponding to the visual axis of the eye, the pocket being configured to receive the mask; and    placing the mask in the pocket such that the mask axis corresponds with the visual axis of the eye.    
     
     
         26 . The method of  claim 25 , wherein placing the mask comprises placing the mask in the pocket such that the mask axis is collinear with the visual axis of the eye.  
     
     
         27 . The method of  claim 1 , wherein applying the mask to the eye of the patient further comprises maintaining the alignment of the mask axis and the visual axis of the eye.  
     
     
         28 . A method for increasing the depth of focus of a eye of a patient, the eye comprising a visual axis and a cornea comprising an epithelial sheet, a Bowman's membrane, and a stroma, the method comprising: 
 locating the visual axis of the eye using more than one reference target;    aligning a mask comprising a pin-hole aperture having a mask axis with the visual axis of the eye; and    applying the mask to the eye while maintaining the alignment of the mask axis and the visual axis.    
     
     
         29 . The method of  claim 28 , wherein locating the visual axis of the eye further comprises: 
 aligning the visual axis of the eye with an instrument axis of an ophthalmic instrument, said instrument having an aperture through which the patient may look along the instrument axis, said aligning comprising: 
 imaging a first reference target on the instrument axis with the ophthalmic instrument at a first distance with respect to the eye;  
 imaging a second reference target on the instrument axis with the ophthalmic instrument, said second reference target being imaged at a second distance greater than the first distance with respect to the eye; and  
 effecting movement of the eye to a position where the images of the first and second reference targets appear in alignment as viewed by the eye.  
   
     
     
         30 . A method for correcting vision, comprising: 
 performing a LASIK procedure;    moving the eye until at least two reference targets are aligned; and    applying a mask to the eye.    
     
     
         31 . An apparatus for aligning a mask with a visual axis of an eye of a patient, the apparatus comprising: 
 an optics housing defining an aperterture at a first location into which the eye may be directed and an instrument axis;    a first target coupled with the optics housing, the first target being positioned on the instrument axis at a first distance relative to the first location;    a second target coupled with the optics housing, the second target beings positioned on the instrument axis at a second distance relative to the first location;    a lens coupled with the optics housing, the second distance being equal to the focal length of the lens; and    a light source off-set from the instrument axis configured to indicate the location of the visual axis of the eye.    
     
     
         32 . The apparatus of  claim 31 , wherein the optics housing comprises a beamsplitter positioned on the instrument axis to intercept light from the marker and direct the light toward the aperture.  
     
     
         33 . The apparatus of  claim 31 , wherein the optics housing comprises a mirror configured to be moved into positioned on the instrument axis to intercept light from the marker and direct the light toward the aperture.  
     
     
         34 . The apparatus of  claim 31 , wherein the first distance is less than the second distance.  
     
     
         35 . 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 the 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.    
     
     
         36 . The apparatus of  claim 35 , 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.  
     
     
         37 . The apparatus of  claim 35 , wherein the marker comprises a light source and at marking target, the light source configured to project an image of the marking target onto the eye.  
     
     
         38 . The apparatus of  claim 35 , further comprising a fixture for locating the eye at a first location.  
     
     
         39 . The apparatus of  claim 35 , further comprising a beamsplitter positioned on the instrument axis to intercept light from the marker and direct the light toward the aperture.  
     
     
         40 . The apparatus of  claim 35 , further comprising a mirror configured to be moved into positioned on the instrument axis to intercept light from the marker and direct the light toward the aperture.  
     
     
         41 . The apparatus of  claim 35 , 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.  
     
     
         42 . The apparatus of  claim 35 , wherein the first distance is less than the second distance.  
     
     
         43 . A method of treating a patient, comprising the steps of: 
 identifying a reference point on a cornea;    marking the reference point;    lifting a corneal flap to expose an intracorneal surface;    positioning an implant on the intracorneal surface; and    closing the flap to cover at least a portion of the implant.    
     
     
         44 . A method of treating a patient as in  claim 43 , wherein the marking step comprises marking a dye on the cornea.  
     
     
         45 . A method of treating a patient as in  claim 43 , wherein the marking step comprises making an impression on the cornea.  
     
     
         46 . A method of treating a patient as in  claim 45 , wherein the marking step comprises delivering a dye to the impression.  
     
     
         47 . A method of treating a patient as in  claim 43 , wherein the marking step comprises illuminating a light on the cornea.  
     
     
         48 . A method of treating a patient as in  claim 43 , wherein the marking step comprises making a mark indicative of the location of the visual axis of the eye.  
     
     
         49 . A method of treating a patient as in  claim 48 , wherein the marking step comprises making a mark approximately at the intersection of the visual axis and a surface of the cornea.  
     
     
         50 . A method of treating a patient as in  claim 48 , wherein the marking step comprises making a mark approximately radially symmetrically disposed about the intersection of the visual axis and a surface of the cornea.  
     
     
         51 . A method of treating a patient as in  claim 43 , wherein the intracorneal surface is on the flap.  
     
     
         52 . A method of treating a patient as in  claim 43 , wherein the intracorneal surface is on an exposed surface of the cornea from which the flap was removed.  
     
     
         53 . A method of treating a patient as in  claim 52 , further comprising applying pressure to the implant to move the implant into alignment with the reference point.  
     
     
         54 . A method of treating a patient as in  claim 51 , wherein the closing the flap step comprises returning the flap with the implant thereon to the cornea.  
     
     
         55 . A method of treating a patient as in  claim 54 , further comprising applying pressure to the implant to move the implant into alignment with the reference point.  
     
     
         56 . A method of treating a patient as in  claim 43 , additionally comprising the step of laying the corneal flap on an adjacent surface of the cornea.  
     
     
         57 . A method of treating a patient as in  claim 43 , additionally comprising the step of laying the corneal flap on a removable support.  
     
     
         58 . A method of treating a patient as in  claim 57 , wherein the support comprises a sponge.  
     
     
         59 . A method of treating a patient as in  claim 57 , wherein the support comprises a surface which is configured to maintain the curvature of the flap.  
     
     
         60 . A method of treating a patient as in  claim 43 , wherein the identifying step comprises illuminating a light spot on the intracorneal surface.  
     
     
         61 . A method of treating a patient as in  claim 60 , wherein the light comprises red light.  
     
     
         62 . A method of treating a patient as in  claim 60 , wherein the identifying step additionally comprises placing a liquid on the intracorneal surface.  
     
     
         63 . A method of treating a patient, comprising the steps of: 
 identifying a reference point on a cornea;    marking the reference point;    creating a corneal pocket to expose an intracorneal surface;    positioning an implant on the intracorneal surface.    
     
     
         64 . A method of treating a patient as in  claim 63 , wherein the marking step comprises marking a dye on the cornea.  
     
     
         65 . A method of treating a patient as in  claim 63 , wherein the marking step comprises making an impression on the cornea.  
     
     
         66 . A method of treating a patient as in  claim 65 , wherein the marking step comprises delivering a dye to the impression.  
     
     
         67 . A method of treating a patient as in  claim 63 , wherein the marking step comprises illuminating a light on the cornea.  
     
     
         68 . A method of treating a patient as in  claim 63 , wherein the marking step comprises making a mark indicative of the location of the visual axis of the eye.  
     
     
         69 . A method of treating a patient as in  claim 68 , wherein the marking step comprises making a mark approximately at the intersection of the visual axis and a surface of the cornea.  
     
     
         70 . A method of treating a patient as in  claim 68 , wherein the marking step comprises making a mark approximately radially symmetrically disposed about the intersection of the visual axis and a surface of the cornea.  
     
     
         71 . A method of treating a patient as in  claim 63 , wherein the identifying step comprises illuminating a light spot on the cornea.  
     
     
         72 . A method of treating a patient as in  claim 71 , wherein the light comprises red light.  
     
     
         73 . A method of treating a patient as in  claim 63 , wherein the creating step comprises creating a pocket at a depth within the range of from about 50 to about 300 from the anterior surface of the cornea.  
     
     
         74 . A method of treating a patient as in  claim 63 , further comprising applying pressure to the implant to move the implant into alignment with the reference point.  
     
     
         75 . A method of treating a patient, comprising the steps of: 
 identifying a reference point on a cornea;    marking the reference point;    exposing a stromal surface;    positioning an implant on the stromal surface; and    covering at least a portion of the implant.    
     
     
         76 . A method of treating a patient as in  claim 75 , wherein the exposing a stromal surface step comprises lifting an epithelial layer to expose stroma.  
     
     
         77 . A method of treating a patient as in  claim 75 , wherein the exposing a stromal surface step comprises removing an epithelial layer to expose stroma.  
     
     
         78 . A method of treating a patient as in  claim 76 , additionally comprising the step of replacing the epithelial layer to at least partially cover the implant.  
     
     
         79 . A method of treating a patient as in  claim 77 , additionally comprising the step of replacing the epithelial layer to at least partially cover the implant.  
     
     
         80 . A method of treating a patient as in  claim 75 , wherein the marking step comprises marking a dye on the cornea.  
     
     
         81 . A method of treating a patient as in  claim 75 , wherein the marking step comprises making an impression on the cornea.  
     
     
         82 . A method of treating a patient as in  claim 81 , wherein the marking step comprises delivering a dye to the impression.  
     
     
         83 . A method of treating a patient as in  claim 75 , wherein the marking step comprises illuminating a light on the cornea.  
     
     
         84 . A method of treating a patient as in  claim 75 , wherein the marking step comprises making a mark indicative of the location of the visual axis of the eye.  
     
     
         85 . A method of treating a patient as in  claim 84 , wherein the marking step comprises making a mark approximately at the intersection of the visual axis and a surface of the cornea.  
     
     
         86 . A method of treating a patient as in  claim 84 , wherein the marking step comprises making a mark approximately radially symmetrically disposed about the intersection of the visual axis and a surface of the cornea.  
     
     
         87 . A method of treating a patient as in  claim 75 , wherein the stromal surface is on a corneal flap.  
     
     
         88 . A method of treating a patient as in  claim 87 , further comprising applying pressure to the implant to move the implant into alignment with the reference point.  
     
     
         89 . A method of treating a patient as in  claim 75 , wherein the stromal surface is on an exposed surface of the cornea from which a flap was removed  
     
     
         90 . A method of treating a patient as in  claim 89 , further comprising applying pressure to the implant to move the implant into alignment with the reference point.  
     
     
         91 . A method of treating a patient as in  claim 75 , wherein the covering step comprises returning a flap with the implant thereon to the cornea.  
     
     
         92 . A method of treating a patient as in  claim 75 , additionally comprising the step of laying a corneal flap on an adjacent surface of the cornea.  
     
     
         93 . A method of treating a patient as in  claim 75 , additionally comprising the step of laying a corneal flap on a removable support.  
     
     
         94 . A method of treating a patient as in  claim 93 , wherein the support comprises a sponge.  
     
     
         95 . A method of treating a patient as in  claim 93 , wherein the support comprises a surface which is configured to maintain the curvature of the flap.  
     
     
         96 . A method of treating a patient as in  claim 75 , wherein the identifying step comprises illuminating a light spot on the cornea.  
     
     
         97 . A method of treating a patient as in  claim 96 , wherein the light comprises red light.  
     
     
         98 . A method of treating a patient as in  claim 75 , wherein the identifying step additionally comprises placing a liquid on the stromal surface.