System and method for accurate optical treatment of an eye's fundus

Abstract

A system and method is provided to accurately treat sites on an eye's retina employing computer based image generation, processing and central control means in conjunction with diode laser sources and optical fibers. The system is designed such that different photocoagulation and photochemical treatment methods alone or in combination can be performed and controlled to for simultaneous or consecutive treatment. The system and method accurately determines geometry of a treatment zone of a specific eye's fundus and adjust a treatment beam to irradiate the treatment zone with minimal coverage of adjacent tissue. Accordingly, also “forbidden zones” which would be severely damaged by the treatment beam are determined and their irradiation is prevented. The treatment zone is accurately determined with digital processing of angiographic data and slit lamp image data. Such image processing includes matching or alignment of two distinct images. This information is integrated with information on the treatment beam characteristics to better match treatment beam coverage with minimal overlap with healthy areas of the fundus. Additionally preferred embodiments also have the ability to automatically track eye movement and switch the beam source depending on eye movement, adjusting the beam spot area in real time.

What is claimed is:  
     
         1 . A system for improved, accurate treatment of an eye's fundus comprising: 
 at least one optical setup for irradiating an eye's fundus with light emitted by a primary light source;    at least one device to take optical images of said fundus;    at least one secondary light source to generate a reference digital image on an eye's retina at a predetermined basic position of a treatment beam imaging optical system;    at least one computer based setup for controlling and for digital image processing to accurately determine a treatment zone;    means for simultaneous generation of a native digital image of said fundus;    a unique marking of said treatment zone on said digital fundus image, creating a digital reference image;    an adjustment means; and    wherein within one device, through said digital image processing and said adjustment means, said at least one optical setup for irradiating said fundus is adjusted to provide optimal irradiation characteristics to perform an improved, accurate treatment.    
     
     
         2 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , wherein said at least one optical setup is capable of emitting different wavelengths with variable power densities to be applied in different photocoagulation and photochemical treatments.  
     
     
         3 . The system for improved, accurate treatment of an eye's fundus according to  claim 2 , wherein said different photocoagulation and photochemical treatments are selected from the group consisting of short-pulse coagulation, long-pulse coagulation, green laser, transpupillary thermotherapy and photodynamic therapy.  
     
     
         4 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , further comprising: 
 means to uniquely mark “forbidden zones” which are not allowed to be irradiated on said digital image of said fundus; and    means to make a digital reference image used for adjustment of said treatment optical system to avoid irradiating said forbidden zones with said at least one primary light source.    
     
     
         5 . The system for improved, accurate treatment of an eye's fundus according to  claim 2 , further comprising means to combine said different treatments.  
     
     
         6 . The system for improved, accurate treatment of an eye's fundus according to  claim 2 , further comprising means to automatically and semi-automatically control said at least one treatment beam for said different photocoagulation and photochemical treatments.  
     
     
         7 . The system for improved, accurate treatment of an eye's fundus according to  claim 6 , further comprising means to controllably apply said at least one treatment beam of said different treatments to a same area, whereby said different photocoagulation and photochemical treatments can be applied simultaneously or consecutively within a single treatment.  
     
     
         8 . The system for improved, accurate treatment of an eye's fundus according to  claim 6 , further comprising means to controllably apply said at least one treatment beam of said different treatments to different treatment areas.  
     
     
         9 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , further comprising: 
 means for loading, displaying and processing a digital image of said fundus provided diagnostically by means of fluorescence angiography;    means for generating a native digital image of said fundus; and    means to align said native digital image by suitable mathematical algorithms with said loaded previously generated digital image generated by fluorescence angiography means to obtain a unique correlation between coordinate systems for these two images.    
     
     
         10 . The system for improved, accurate treatment of an eye's fundus according to  claim 9 , wherein said means to align is an automatically operating pattern recognition means.  
     
     
         11 . The system for improved, accurate treatment of an eye's fundus according to  claim 9 , wherein said means to align said native and previously generated images is at least two reference points manually marked in each of said images, and said images are said native fundus digital image and said loaded previously generated digital image from said diagnostic fluorescence angiography.  
     
     
         12 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , further comprising: 
 at least one variable aperture;    an optical system to image said aperture onto said treatment zone on said retina; and    an additional optical system to image said treatment beam onto said variable aperture.    
     
     
         13 . The system for improved, accurate treatment of an eye's fundus according to  claim 12 , wherein said treatment beam has a radiation intensity profile with a rectangular shape otherwise known as a top hat shape.  
     
     
         14 . The system for improved, accurate treatment of an eye's fundus according to  claim 13 , wherein said image generated on said retina has a polygonal shape which is selected from the group consisting of substantially circular, substantially oval, substantially rectangular, and preferably square.  
     
     
         15 . The system for improved, accurate treatment of an eye's fundus according to  claim 13 , further comprising at least one additional aperture, having a different shape from said variable apertures, which can be sequentially applied to create images on said retina of shapes more complicated than simple polygons.  
     
     
         16 . The system for improved, accurate treatment of an eye's fundus according to  claim 15 , wherein said variable and additional apertures are independently variable and can be adjusted to a desired size by a method selected from the group consisting of manual, manual with electronic aids, electrochemical, and completely automatic.  
     
     
         17 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , wherein said at least one primary light source is selected from the group consisting of a laser, a diode laser, a luminescent diode, and at least one optical fiber whose opposite end is coupled to at least one laser.  
     
     
         18 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , wherein said secondary light source operates at a wavelength different than that of said primary light source and said secondary light source is selected from the group consisting of a laser, a diode laser, and a luminescent diode.  
     
     
         19 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , further comprising: 
 at least two variable orthogonal mirrors;    at least one imaging optical system and an automatic primary beam switch; and    scanning means, wherein these components adjust said treatment beam create a two dimensional image on said treatment zone on said retina.    
     
     
         20 . The system for improved, accurate treatment of an eye's fundus according to  claim 19 , wherein said imaging optical system is variable and preferably replaceable.  
     
     
         21 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , wherein said adjustment means further comprises: 
 a micro-mirror device where each mirror can be addressed individually; and    at least one optical imaging system.    
     
     
         22 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , wherein said adjustment means further comprises: 
 a liquid crystal device where each pixel can be addressed individually including a polarizer and an analyzer; and    at least one optical imaging system.    
     
     
         23 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , further comprising: 
 at least two variable, linear, orthogonal-arranged position devices;    an automatic primary beam power switch; and    whereby scanning an end of an optical fiber that transfers said treatment beam with said position devices creates an arbitrary two dimensional region on said retina.    
     
     
         24 . The system for improved, accurate treatment of an eye's fundus according to  claim 23 , wherein said position devices comprise piezoelectric elements.  
     
     
         25 . The system for improved, accurate treatment of an eye's fundus according to  claim 23 , further comprising: 
 an optical system;    a contact lens on a cornea of an eye to be treated to image said two dimensional region onto said retina;    wherein a shape of said two dimensional region generated on said retina conforms exactly to a shape of said treatment zone; and    wherein said optical system is variable and preferably replaceable.    
     
     
         26 . The system for improved, accurate treatment of an eye's fundus according to  claim 12 , wherein said optical system to image said aperture onto said treatment zone comprises at least one lens.  
     
     
         27 . The system for improved, accurate treatment of an eye's fundus according to  claim 12 , wherein said optical system to image said aperture onto said treatment zone comprises an optical module of a commercial camcorder.  
     
     
         28 . The system for improved, accurate treatment of an eye's fundus according to  claim 1 , further comprising at least one contact lens positioned on a cornea of said eye, and wherein said retina can be observed directly via an eyepiece.  
     
     
         29 . An improved, accurate method of treatment of an eye's fundus, using an optical treatment system, preferably with a slit lamp assembly, comprising the steps of: 
 a. generating a treatment beam from a primary light source;    b. generating a digital reference image preferably by means of fluorescence angiography, using a secondary light source, on an eye's retina at a predetermined position of said treatment beam's imaging optical system, wherein said secondary light source preferably operates at a different wavelength from said primary light source;    c. controlling and processing said digital reference image by at least one computer to accurately determine a treatment zone;    d. simultaneously generating a native digital image of said fundus;    e. uniquely marking said treatment zone onto a corresponding region of said native digital image of said fundus; and    f. adjusting said treatment beam and said optical treatment system to have said treatment beam cover said treatment zone and optimally irradiate said treatment zone.    
     
     
         30 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , further comprising the steps of: 
 g. uniquely marking “forbidden zones” which are not allowed to be irradiated on said digital reference fundus image; and    h. adjusting said treatment beam and said optical treatment system to have said treatment beam avoid said forbidden zones.    
     
     
         31 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , wherein said method of treatment is a combination of different photocoagulation and photochemical treatments; 
 wherein said photocoagulation treatments are chosen from the group consisting of short-pulse photocoagulation and long pulse photocoagulation; and    wherein said photochemical treatments are chosen from the group consisting of green laser, transpupillary thermotherapy, and photodynamic therapy.    
     
     
         32 . The improved, accurate method of treatment of an eye's fundus according to  claim 31 , wherein said different photocoagulation and photochemical treatments are controllably applied to selectively switch between simultaneous and consecutive treatment of a treatment area within a single treatment.  
     
     
         33 . The improved, accurate method of treatment of an eye's fundus according to  claim 31 , wherein said different treatments are controllably applied to different treatment areas.  
     
     
         34 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , wherein said adjusting said treatment beam is accomplished by a method selected from the group consisting of manual completion by an operator, assistance by an electronic means, preferably with optical or acoustical signals, and full automation.  
     
     
         35 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , further comprising the steps of: 
 d(1). aligning said native digital image of said fundus with said image of said treatment zone by applying suitable mathematical algorithms to correlate between coordinate systems for these two images, wherein said aligning is accomplished by one of the following methods: an automatically operating pattern recognition scheme, and manually marking at least two reference points in each image;    
     
     
         36 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , wherein said step of adjusting said treatment beam is accomplished by illuminating and imaging at least one variable aperture having an optical system onto said treatment zone on said retina and imaging said treatment beam onto said variable aperture and onto said retina to create pre-selected polygonal shapes.  
     
     
         37 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , wherein said step of adjusting said treatment beam is accomplished by sequentially illuminating and imaging at least two apertures having different shapes to generate said image on said retina in more complicated shapes than simple polygons.  
     
     
         38 . The improved, accurate method of treatment of an eye's fundus according to  claim 37 , wherein said apertures are varied independently of each other and adjusted to a desired size by a method selected from the group consisting of manual, semi-automatic and automatic means.  
     
     
         39 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , wherein said step of adjusting said treatment beam is accomplished by scanning with at least two variable, linear, orthogonal-arranged devices and using an automatic primary beam power switch to create an arbitrary-shaped two dimensional region substantially equivalent to said treatment zone.  
     
     
         40 . The improved, accurate method of treatment of an eye's fundus according to  claim 39 , wherein said scanning of said treatment beam over said treatment zone irradiates each point in the treatment zone for a predetermined period of time.  
     
     
         41 . The improved, accurate method of treatment of an eye's fundus according to  claim 39 , wherein said step of adjusting said treatment beam is accomplished by a method selected from the group consisting of manual adjustment by an operator, assistance by electronic means, preferably with optical or acoustical signals, and fully automatic adjustment.  
     
     
         42 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , wherein said secondary light source operates preferably at a green wavelength, and wherein said secondary light source produces an image containing at least one shape chosen from the group consisting of a ring and a cruciform.  
     
     
         43 . The improved, accurate method of treatment of an eye's fundus according to  claim 36 , wherein an image of said treatment beam is positioned manually on said retina, preferably being positioned there by at least one secondary target spot and wherein said native digital image of said fundus is generated in real time, and said position of said treatment spot area is determined electronically and transformed into said coordinate system of said diagnostic fluorescence angiography and displayed thereon.  
     
     
         44 . The improved, accurate method of treatment of an eye's fundus according to  claim 43 , wherein in real time said position of said treatment zone is determined and said treatment light source is appropriately switched on and off; 
 wherein said native image of said fundus containing said spot of said treatment beam and said image generated diagnostically by fluorescence angiography means are digitally processed, superimposed and presented on a display device; and    wherein in real time said position of said treatment zone is determined and said treatment beam spot is positioned in real time according to said treatment beam spot position.    
     
     
         45 . The improved, accurate method of treatment of an eye's fundus according to  claim 44 , wherein in real time said position of said treatment zone is calculated from a point that is positioned selected from the group of locations consisting of a retina and a cornea and not including the treatment zone itself.  
     
     
         46 . The improved, accurate method of treatment of an eye's fundus according to  claim 29 , further comprising the step of: 
 g. varying power of said treatment beam generated by said primary light source, to compensate for optical losses occurring along said optical path, in order to keep constant power on said retina.