WO1991005515A1

WO1991005515A1 - Fibre bundle coupled ophthalmic laser

Info

Publication number: WO1991005515A1
Application number: PCT/AU1990/000500
Authority: WO
Inventors: John Leonard Hughes
Original assignee: Australian Electro Optics Pty. Ltd.
Priority date: 1989-10-19
Filing date: 1990-10-19
Publication date: 1991-05-02

Abstract

This invention relates to a laser based, computer controlled ophthalmic system where the eye (1) is treated via pupil (2) by the laser beam (3) whilst its structure is being illuminated by ordinary light (4) and recorded via scattered light (5) collected by the aperture (6) of a coherently polished, single mode optical fibre bundle (7), said components being enclosed in a portable unit (8) which fits snugly around the patient's eye (9). Fibre bundle (7) connects head unit (8) to a remotely sited unit under the control of the ophthalmologist, said unit containing lasers (17, 18 and 19) and white light source (11), neural computer (21), display monitor (22) and control module (23) which allows the ophthalmologist to override the control signal generated by the computer as the need arises.

Description

Fibre Bundle Coupled Opthalmic Laser

Field of the Invention

This invention relates to a fibre bundle coupled, opthalmic laser system consisting of a head module which can be attached to the patient's head, said head module being fibre bundle coupled to an optical module containing a source of white light, laser beam sources, beam splitter arrays and an opto-electronic camera, said optical module being connected to a computer module which controls the operation of said system, the preferred computer module being that of an artificial neural computer, said computer module in turn being connected to a display monitor, the remaining module being the control module which is operated by the opthalmologist.

The invention has application in opthalmology.

Summary of the Prior Art Prior art laser opthalmic systems consisted of a slit lamp- microscope assembly in which the laser beam generator was added in a manner which minimised departures from the pre-laser art of opthalmology. These prior art laser opthalmic systems placed a severe strain, particularly on elderly patients in that their heads had to be strapped into a rigid frame some times for hours at a time whilst the opthalmologist repeatedly fired what was essentially a single shot laser beam into the eye, also placing undue strain on the opthalmologist in the process. Furthermore, these prior art laser opthalmic systems using powerful pulsed lasers emitting outside the visible region required a low power visible laser beam to align the high power beam within the eye of the patient due to both wavelength and power differences of the

5 primary laser beam.

The present invention overcomes the severe defects of prior art laser opthalmic systems in that it eliminates the need for patients to be strapped into the rigid framework of the system as a whole by providing a compact, portable head module which can be ι o attached to the patient's head allowing, for example, elderly patients to remain in bed whilst undergoing treatment. Furthermore, by fibre coupling said portable head to the other modules, the opthalmologist can be remotely sited, looking after one or more patients simultaneously via computer control which

15 can be overridden if required. When using neural network computers, the invention can be taught to perform the work of the opthaimologists who then only needs to oversee the actual treatment procedures.

Background of the Invention 0 Opthalmology has benefitted enormously from the advent of the laser because, for the first time, the eye, which can be considered as a very sophisticated optical system, can be repaired by passing a laser beam through its internal optics in a manner which can be accurately controlled by the opthalmologist, at optical power 5 levels which cannot be achieved with ordinary light. However, opthalmologists are an extremely conservative group of professionals, for obvious reasons, and it has proved to be very difficult to provide them with equipment which fully optimises the role of the laser in this field of expertise. Having grown used to the well established slit lamp system as the standard, and relatively low cost method of treating patients, the first introduction of lasers into opthamology has been centred on attaching the laser in one form or another onto a slit lamp system. This approach involves the patient's head having to be strapped into the said slit lamp assembly whilst the laser beam is directed into the patient's eye, its path being superimposed on the optical path of the slit lamp, a process which really allows for only the minimal realisation of the laser's potential in opthalmology. In a major departure from the accepted practices of opthalmology, the present invention first of all removes the need for the patient, in particular elderly patients, to be strapped into the medieval head frames of slit lamp systems.

This is achieved by placing a module over the patient's eye which is attached to the patient's head only. The module contains what is essentially an electro-optics eye itself in the form of the coherently packed output aperture of a bundle of single mode optical fibres which act as both a transmitter of light into the eye and a means of collecting the reflected light in such a manner that an image of the internal structure of the patient's eye can be displayed at a remote site where it can be viewed by the opthalmologist and assessed by a neural network controlled artificial intelligence unit which learns the art of opthalmology with experience.

The invention can be used by a single opthalmologist to treat several patients simultaneously.

Summary of the Invention

5 It is an object of the invention to provide an opthalmic system which minimises stress on the patient, in particularly elderly patients, by providing a modular system with one of the modules being portable and strapped to the patient's head so that said patient can lie down in bed whilst being treated from the remotely ι o sited modules of the invention which are under the control of an opthalmologist.

Another object of the invention is to provide a coherently packed, single mode fibre bundle to optically link the two sections of the invention together, to transmit ordinary light and laser light

15 into the patient's eye and to convey the light scattered out of the patient's eye which is collected by the said fibre bundle back into the remotely sited modules, which are under the control of the opthalmologist, and which convert said collect light into an image of the internal structure of said patient's eye. 0 It is an object of the invention to illuminate the patient's eye internally with ordinary light and to record and display the internal structure of said eye at a remote site.

Another object of the invention is to allow a laser beam passed along said fibre bundle to said eye to be focused precisely onto any 5 selected portion of the displayed internal image of said eye. It is an object of the invention to allow for the collection into the end of the fibre bundle over the patient's eye sufficient light scattered from said eye that is necessary to form the image of the internal structure of said eye.

5 Another object of the invention is to provide laser light of a wavelength appropriate to the various operations that have to be performed on both the internal and/or external areas of the said human eye.

It is an object of the invention to illuminate the human eye ι o with both pulsed and continuous laser beams.

Brief Description of the Drawings

A better understanding of the invention may be obtained from the following considerations taken in conjunction with the accompanying drawing which is not meant to limit the scope of the i s invention in any way.

Figure 1 shows the layout of the invention with the portable head module attached to the patient's head and fibre bundle coupled to the remotely sited optical, computer, display and control module of the invention.

0 Detailed Description of the Invention

In Figure 1 , numeral 1 indicates the patient's eye whilst numeral 2 indicates the pupil of said eye through which both the laser beam and the white light viewing beam indicated by numerals 3 and 4 respectively enter eye 1. Numeral 5 indicates the light 5 energy reflected and scattered from within eye 1 and off its outside surface, into the concave surface indicated by numeral 6 of the fibre bundle of the invention indicated by numeral 7.

In Figure 1 , numeral 8 indicates the casing of the head module of the invention which is strapped around the patient's head to

5 snugly fit around the eye as indicated by numeral 9.

Numeral 10 indicates a micro lens array to couple the fibre cores, when the said fibre core diameters are less than the fibre cladding thickness, into a collimated beam in the case of incoherent light and into a phase locked beam in the case of laser light. In the ι o case when the fibre core diameter exceeds the fibre cladding thickness, the micro lens array 10 may be dispensed with. Numeral 11 indicates a source of white light to illuminate eye 1 in full colour whilst numeral 12 indicates a light beam splitter to direct part of said white light incident from 11 into fibre bundle 7.

15 Numeral 13 indicates a partial reflector to direct laser light from the beam splitters indicated by numeral 14, 15 and the fully reflecting mirror indicated by numeral 16 from laser sources indicated by numerals 17, 18 and 19 respectively into fibre bundle 7. Numeral 20 indicates an opto-electronic camera which views 0 the eye via reflected and scattered light 5 via fibre bundle 7. in Figure 1 , numeral 21 indicates a computer module in a preferred format of an artificial neural computer. Numeral 22 indicates a display monitor which allows the internal structure of eye 1 to be viewed by the opthalmologist in the detail necessary for 5 the most intricate operation to then be performed. Numeral 23 indicates a control unit which allows the opthalmologist to override computer module 21 when performing the eye surgery. However, artificial neural computers have the ability to learn and remember the procedures of the best opthalmoiogists both individually and as a group and the invention, after the due learning processes, will be able to perform eye operations itself as it has

5 been taught and gained from its experience.

In Figure 1 , numeral 24 indicates a movable joint which allows relative movement between fibre bundle 7 and housing 8. Numerals 25 indicates the positioners which adjust output surface 6 of fibre bundle 7 relative to eye 1 via pupil 2. Numeral 26 indicates an ι o optical fibre or wire coupler which conveys the information from computer module 21 to positioners 25 to accurately adjust surface 6 relative to eye 1.

It should be noted that surface 6 of fibre bundle 7 acts as a coherent and incoherent optical transmitter and receiver unit. In

15 the incoherent mode, white light from source 11 simply floods eye 1 and the reflected and scattered light 5 is picked up by detector 20. On the other hand, when coherent sources 17, 18 and 19 are used, parts or the whole of surface 6 can act as transmitting apertures for blue, green, red and infra red light of scaleable power

2o levels.

The invention has application for opthalmic operations from a remote site on one or more patients whilst the patient lies in bed rather than being strapped onto a fixed head rest for hours at a time in some instances.

25 The system allows for a full screen, full colour display of the internal structures of the patient's eye with a detailed record being made of all operating procedures together with their results. The invention can be used to disperse secondary cataracts, re- attach retinas, seal blood vessels, treat tumors, and also profile the outside of the eye ball with ultra violet light by replacing light source 11 with an ultra violet laser 11 , 1 to profile eye 1 , and laser sources 17, 18 and 19 as illuminators, and for aiming the UV beam from generator 11.

Claims

I claim,

1. An opthalmic laser system consisting of two units, namely a portable unit which is comfortably located on the head of the patient covering the eye to be treated and a second unit, remotely

5 sited from said patient undergoing treatment and optically coupled to the said first unit located on said patient by a coherently packed, bundle of single mode fibres, said second unit consisting of laser beam generators, a white light source, a neural computer, an image display monitor and a control unit used by the opthalmologist to ι o override the instructions of the neural computer, said portable unit consisting of said bundle of optical fibres whose end faces are compacted into a concave output face which directs white light into the patient's eye from wherein it is scattered, picked up by the same said bundle and conveyed back into the second unit so that an

15 image of the internal structure of the patient's eye can be displayed and accurately monitored by the opthalmologist.

2. A system as claimed in Claim 1 where the displayed image of the patient's eye can be processed by the neural computer which in turn automatically fires a laser beam along said fibre bundle into ] o said eye allowing for the treatment of that portion of the patient's damaged eye in need of repair.

3. A system as claimed in Claim 1 where the laser beam is focused onto a secondary cataract in said patient's eye as processed by the neural computer. 5 4. A system as claimed in Claim 1 where the laser beam is focused well into the eye so that blood vessels can be treated, particularly in elderly patients.

5. A system as claimed in Claim 1 where ultra violet laser beams generated in the remotely sited unit are transported along a fibre bundle into said portable head and focused onto the outside of the eye of said patient so as to re-profile said surface of said eye.

5

6. A system as claimed in Claim 1 where the output laser beam entering the eye is pulsed.

7. A system as claimed in Claim 1 where the output laser beam entering the eye is continuous.

8. A system as claimed in Claim 1 where the laser light switched ι o from the patient's eye at low power can be imaged in such a manner as to pin point the particular part of the patient's eye where the higher power laser beam has to be focused.

9. A system as claimed in Claim 1 where the laser beam is only emitted over a portion of the end face of said fibre bundle output

15 face.