Devices and methods for harvesting limbal stem cells

Abstract

A system, apparatus and method for harvesting from the eye of a mammilian (e.g., cadaveric) donor a disc-shaped graft or lenticle consisting of corneal tissue and a quantity of scleral or pericorneal tissue wherein limbal stem cells are located. This graft or lenticle is then transplanted onto the eye of a human or veterinary patient to treat a disorder caused by the absence or deficiency of limbal stem cells in the patient's eye. The system of the present invention comprises a) an eye-contacting ring and cutter guide apparatus and b) a cutter apparatus. The eye-contacting ring and cutter guide apparatus is initially placed in contact with the donor eye such that a portion of the cornea and adjacent scleral or pericorneal tissue containing limbal stem cells protrudes upwardly through the center of the ring. The cutter is then engaged with guide member(s) formed on the ring and the cutter is advanced, severing the protruding cornea and stem-cell-containing pericorneal tissue. In this manner the desired lenticle is obtained for subsequent transplantation.

What is claimed is:  
     
         1 . A system for harvesting from a mammalian eye a desired quantity of corneal tissue along with a desired quantity of pericorneal tissue that contains limbal stem cells, the system comprising: 
 (a) an eye-contacting ring and guide member; and,    (b) a cutter;    and wherein;    (c) the eye-contacting ring and guide member comprises a ring member having an upper surface and a lower surface and a cutter guide for guiding the cutter along a predetermined path a spaced distance above the upper surface of the ring member;    (d) the cutter comprises a blade for cutting the corneal and adjacent scleral tissue; and,    (e) the ring member is sized such that when its lower surface is placed in contact with the anterior aspect of the eye, a portion of the cornea and adjacent pericorneal tissue containing limbal stem cells protrudes upwardly through the ring member above the ring member's upper surface and in relation to the cutter guide such that when the cutter is advanced along the cutter guide it will remove the desired quantity of corneal tissue along with the desired quantity of pericorneal tissue containing stem cells.    
     
     
         2 . A system of  claim 1  further comprising an oscillator connected to the blade, the oscillator causing the blade to oscillate.  
     
     
         3 . A system of  claim 2  wherein the oscillator is pneumatic.  
     
     
         4 . A system of  claim 1  wherein the ring member is secured to the eye.  
     
     
         5 . A system of  claim 1  wherein the ring member is secured to the eye by a partial vacuum.  
     
     
         6 . A system according to  claim 5  wherein the system further comprises a vacuum pump for creating the partial vacuum  
     
     
         7 . A system according to  claim 6  wherein the vacuum pump comprises a manually operated, portable vacuum pump.  
     
     
         8 . A system of  claim 5  wherein the partial vacuum is contained within an anular structure, the anular structure comprising two rims of the ring member and a surface of an eye.  
     
     
         9 . A system of  claim 1  wherein an inner diameter of the ring member is about 14 mm to about 30 mm.  
     
     
         10 . A system of  claim 1  wherein an inner diameter of the ring member is about 14 mm to about 24 mm.  
     
     
         11 . A system of  claim 1  wherein an inner diameter of the ring member is about 14 mm to about 18 mm.  
     
     
         12 . A system of  claim 1  wherein an inner diameter of the ring member is about 16 mm.  
     
     
         13 . A system of  claim 1  wherein an inner diameter of the ring member is 16 mm.  
     
     
         14 . A system of  claim 1  wherein the cutter comprises a guide engaging member for use in combination with the eye-contacting ring and guide member.  
     
     
         15 . A system of  claim 1  wherein the ring member comprises a gripping member.  
     
     
         16 . A system of  claim 1  wherein the cutter comprises a maneuvering member whereby the user's hand may control and maneuver the cutter.  
     
     
         17 . A system according to  claim 1  wherein the ring member is sized such that when its lower surface is placed in contact with the anterior aspect of the eye, a portion of the cornea and adjacent scleral tissue protrudes upwardly through the ring member above the ring member's upper surface and in relation to the cutter guide such that when the cutter is advanced along the cutter guide it will remove the desired quantity of corneal tissue along with a desired quantity of scleral tissue including limbal stem cells.  
     
     
         18 . A method for harvesting corneal and scleral tissue of an eye, the method comprising steps of: 
 (a) providing a device for harvesting from a mammalian eye a quantity of corneal tissue along with a quantity of pericorneal tissue containing limbal stem cells, the device comprising: 
 (i) an eye-contacting ring and guide member; and,  
 (ii) a cutter; and,  
 wherein,  
 (iii) the eye-contacting ring and guide member comprises a ring member having a an upper surface and a lower surface and a cutter guide for guiding the cutter along a predetermined path a spaced distance above the upper surface of the ring member;  
 (iv) the cutter comprises a blade for cutting the corneal and adjacent scleral tissue; and,  
 (v) the ring member is sized such that when its lower surface is placed in contact with the anterior aspect of the eye, a portion of the cornea and adjacent pericorneal tissue containing limbal stem cells protrudes upwardly through the ring member above the ring member's upper surface and in relation to the cutter guide such that when the cutter is advanced along the cutter guide it will remove the desired quantity of corneal tissue along with a quantity of pericorneal tissue containg limbal stem cells;  
   (b) placing the lower surface of the ring member in contact with the anterior aspect of the eye such that the cornea and a desired quantity of pericornial tissue containing limbal stem cells protrudes upwardly through the ring member; and,    (c) engaging the cutter with the cutter guide and advancing the cutter along the cutter guide such that blade means severs the desired quantity of corneal tissue along with the pericorneal tissue containing limbal stem cells.    
     
     
         19 . A method of  claim 18  further comprising an oscillator connected to the blade and wherein Step C further comprises using the oscillator to cause the blade to oscillate as the cutter is advanced.  
     
     
         20 . A method of  claim 19  wherein the oscillator is pneumatic.  
     
     
         21 . A method of  claim 18  further comprising the step of securing the ring member to the eye.  
     
     
         22 . A method of  claim 21  wherein the step of securing the ring member to the eye is carried out by forming a partial vacuum between the ring member and the eye.  
     
     
         23 . A method of  claim 22  wherein the ring member further comprises an annular vacuum chamber and wherein the step of securing the ring member to the eye is carried out by forming a partial vacuum within the annular vacuum chamber.  
     
     
         24 . A method of  claim 18  wherein an inner diameter of the ring member is about 14 mm to about 30 mm.  
     
     
         25 . A method of  claim 18  wherein an inner diameter of the ring member is about 14 mm to about 24 mm.  
     
     
         26 . A method of  claim 18  wherein an inner diameter of the ring member is about 14 mm to about 18 mm.  
     
     
         27 . A method of  claim 18  wherein an inner diameter of the ring member is about 16 mm.  
     
     
         28 . A method of  claim 18  wherein an inner diameter of the ring member is 16 mm.  
     
     
         29 . A method of  claim 18  wherein the cutter comprises a guide engaging member for use in combination with the eye-contacting ring and guide member.  
     
     
         30 . A method of  claim 18  wherein the ring member comprises a gripping member and wherein Step B further comprises grasping the gripping member.  
     
     
         31 . A method of  claim 19  wherein the cutter comprises a maneuvering member whereby the user may control and maneuver the cutter and wherein Step c further comprises grasping the maneuvering member and using the maneuvering member to maneuvering member to maneuver the cutter.  
     
     
         31 . A method according to  claim 18  wherein the ring member is sized such that when its lower surface is placed in contact with the anterior aspect of the eye, a portion of the cornea and adjacent scleral tissue protrudes upwardly through the ring member above the ring member's upper surface and in relation to the cutter guide such that when the cutter is advanced along the cutter guide it will remove the desired quantity of corneal tissue along with a desired quantity of scleral tissue including limbal stem cells and wherein Step B comprises placing the ring member on the eye such that the desired quantity of corneal tissue along with a desired quantity of scleral tissue including limbal stem cells protrudes upwardly trough the ring member.  
     
     
         32 . A method according to  claim 23  wherein the system provided in Step A further comprises a portable manually operated vacuum pump and wherein the 18 wherein the partial vacuum is created by manually operating the vacuum pump.  
     
     
         33 . A transplantable lenticular graft comprising a generally disc shaped segment of corneal tissue and a quantity of pericorneal tissue containing limbal stem cells, harvested by a method according to  claim 18.