Method and apparatus for treatment of ocular tissue using combined modalities

Abstract

A method is provided for treating a targeted area of ocular tissue in a tissue-sparing manner comprising use of two or more therapeutic modalities, including thermal radiation source (such as an CW infrared fiber laser), operative in a wavelength range that has a high absorption in water, and photochemical collagen cross-linking (CXL), together with one or more specific system improvements, such as peri-operative feedback measurements for tailoring of the therapeutic modalities, an ocular tissue surface thermal control/cooling mechanism and a source of deuterated water/riboflavin solution in a delivery system targeting ocular tissue in the presence of the ultraviolet radiation. Additional methods of rapid cross-linking (RXL), are provided that enables cross-linking (CXL) therapy to be combined with thermal therapy.

What is claimed is: 
     
         1 . A method for treating ocular tissue comprising:
 directing laser radiation in a high absorption range of water to an ocular surface and subsurface region below the ocular surface, wherein the laser radiation modifies the shape of the ocular surface;   delivering a cross-linking agent at a depth below the irradiated surface of the ocular tissue at or near the subsurface regions; and   directing ultraviolet radiation to the ocular surface to promote collagen cross-linking at or near the subsurface region to stabilize the modified shape of the ocular surface, wherein the cross-linking agent promotes the crosslinking.   
     
     
         2 . The method of  claim 1 , wherein the ocular surface is a cornea surface. 
     
     
         3 . The method of  claim 1 , wherein thermal remodeling of the subsurface region induced by the laser radiation modifies the shape of the ocular surface. 
     
     
         4 . The method of  claim 1 , further comprising cooling the ocular surface to prevent thermal remodeling of the surface region and control temperature of the subsurface regions. 
     
     
         5 . The method of  claim 1 , wherein the ultraviolet radiation is delivered in a pulsed and fractionated format to minimize trauma to ocular tissue and to enhance permeability of the ocular tissue. 
     
     
         6 . The method of  claim 1 , further comprising controlling the temperature of the ocular surface during the laser irradiation, after the laser irradiation, or both in a range from 0 degrees to 20 degrees C. 
     
     
         7 . The method of  claim 1 , wherein the laser radiation is from continuous wave infrared laser. 
     
     
         8 . The method of  claim 1 , wherein the ocular surface is a cornea surface and the laser radiation selectively induces thermal lesions in the stroma without inducing lesions in the epithelium, Bowman's layer, Descemet's membrane, and endothelium membrane. 
     
     
         9 . The method of  claim 1 , wherein the laser radiation selectively induces thermal lesions in the subsurface region at depths below the ocular surface between 100 μm to 400 μm, without inducing thermal lesions above and below the thermal lesions. 
     
     
         10 . The method of  claim 1 , wherein the laser radiation induces lesions in the subsurface region with selected annular widths between 0.2 mm to 1 mm. 
     
     
         11 . An apparatus for treatment of ocular tissue comprising:
 a laser operative in a high absorption range of water for irradiating an ocular surface and inducing lesions in a subsurface region below the ocular surface; and   an ocular surface cooling mechanism comprising a lens for applanating on the ocular surface, the cooling mechanism configured for controlling temperature of the ocular surface irradiated by the laser.   
     
     
         12 . The apparatus of  claim 11 , wherein the laser is a continuous wave infrared fiber laser. 
     
     
         13 . The apparatus of  claim 11 , wherein the applanation lens comprises a sapphire lens. 
     
     
         14 . A method for treating ocular tissue comprising:
 directing laser radiation in a high absorption range of water to an ocular surface and subsurface region below the ocular surface; and   controlling the temperature on the ocular surface to prevent collagen shrinkage while allowing collagen shrinkage in the subsurface region, wherein the collagen shrinkage in the subsurface region modifies the shape of the ocular surface.   
     
     
         15 . The method of  claim 14 , wherein the ocular surface is a cornea surface and the subsurface regions comprise the epithelium and Bowman's layer and the subsurface region comprise the stroma. 
     
     
         16 . The method of  claim 14 , wherein the temperature of the surface regions is controlled during the irradation, after the irradiation, or both in a range less than 40 degrees C. 
     
     
         17 . A method of treating ocular tissue comprising:
 directing a coaxial beam at ocular tissue comprising thermal radiation and OCT light,   wherein the thermal radiation modifies the ocular tissue;   wherein the OCT light provides images of the modification of the ocular tissue; and   adjusting parameters of the treatment of ocular tissue based on the OCT images.   
     
     
         18 . A system for treating ocular tissue comprising:
 a dichroic mirror;   a thermal radiation source that can emit radiation to which the dichroic mirror is highly transparent; and   an OCT light source configured to emit light to which the dichroic mirror is reflective,   wherein the thermal radiation source, the OCT light source, and the mirror are arranged such that radiation transmitted through the mirror and light reflected by the mirror are coaxial.