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Towards Better Eye Care
The ophthalmological industry has seen gigantic leaps in
surgical and instrumentation techniques in the last decade
Dr Lingam Gopal |
Ophthalmology like any other branch of medicine has made significant
progress in the last decade due to technological advances. The advances in this
field are both in instrumentation as well as in surgical techniques.
Advances in Imaging
The ability to visualise various parts of the eye in very fine detail has
improved dramatically with the advent of new imaging techniques. In addition
to improvisations in the microscopes that form an important part of most ophthalmic
instrumentation, true innovative technologies include the use of confocal microscopy,
optical coherence tomography and use of scanning laser ophthalmoscopy. The pentacam
is based on scheimpflug camera and can image a three-dimensional view. Both,
the surfaces of the cornea and the lens, can be evaluated in detail. Confocal
microscope permits the visualisation of very fine details, which are not normally
observed by naked eye. Use of this microscope enables one to literally visualise
an organism such as yeast on the cornea of a patient with corneal ulcer. More
commonly, however, this microscope is used as a research tool. Optical Coherence
Tomography (OCT) is a technique that produces high resolution cross-sectional
images of optical reflectivity. It is based on the principle of low coherence
interferometry and light emitted by diode laser at 840 nm wavelength is used.
This method of examination is predominantly used to evaluate the diseases of
the macula, which is the central part of the retina. Diseases such as macular
hole, age-related macular degeneration are best evaluated by this tool. The
anterior segment OCT is a variation in the theme applicable to evaluate the
front of the eye in great detail—especially the relationship of the iris
and angle of the eye. This study may be useful in the evaluation of some eyes
that may be prone to a condition called narrow angle glaucoma. Scanning laser
polarimetry is yet another advanced imaging tool that has facilitated the imaging
of retinal nerve fiber layer. This could be an important test to detect early
damage due to glaucoma. Scanning laser ophthalmoscopy helps us to image the
surface of the retina and the optic nerve head and hence is used both in the
evaluation of glaucoma-related optic disc damage and in imaging the retina in
diseases such as diabetic retinopathy. In short, the technological advances
in imaging have permitted the ophthalmologists to have access to hitherto unknown
details of the diseases. These details are available without need for biopsy
(sampling) of the tissues. They serve not only as diagnostic tools, but are
important in monitoring the treatment and its efficacy. Since the lasers that
are used during these investigations are of very low power (class one), they
are perfectly safe for evaluation.
Advances in Instrumentation
 In
the field of ophthalmic surgery, advances have been both in instrumentation
and techniques of surgery. The market is literally flooded with newer innovations
and instrumentations everyday. For example, the cataract surgery is performed
now through a very small cut in the eye and the hardened opaque lens is emulsified
using ultrasound energy and sucked out with maximum safety, without needing
any suture. This so-called phacoemulsification has undergone dramatic changes
with newer innovations such as cold phaco and ozil tip. The Intraocular Lenses
(IOL) available to replace the opaque lens are also of high quality flexible
materials and can be pushed into an eye through a small aperture. Newer technology
permits the IOL surface to be selectively altered to correct astigmatism; to
cut off unwanted ultraviolet light or to reduce inflammation. Vitreoretinal
surgery is an approach to deal with difficult problems of the retina and vitreous
and this field has seen tremendous technological advances. The thickness of
the instruments has shrunk significantly. Hence, some of the surgeries can be
potentially done without any sutures. A plethora of intraocular instruments
and agents such as silicone oil, perfluro carbon liquids, perfluorocarbon gases
have permitted the management of very complex retinal diseases which probably
were untreatable even 15 years back.
| Genetics and molecular biology have made tremendous
progress in all fields and this applies to ophthalmology as well. Molecular
biological techniques such as Polymerase Chain Reaction (PCR) permits us
to identify the organisms causing infection within a matter of few hours,
while routine culture methods take several days. The CSIR-NMTILI from India
have devised a DNA chip that permits identification of about five to eight
organisms causing ocular diseases by using the PCR technique. The chip has
been devised in such a way that no major equipment is required to perform
the test and the report should be ready in few hours' time.
The use of newer technologies to map the human
genome has its repercussions in the field of ophthalmology as well. In
addition to identifying predisposition to a disease, it may help in tailor-made
drug prescription in the future. Genetic studies of a disease process
also enable better understanding of the disease and selection of potential
targets for treatment. The other important buzz word is stem cell research.
Stem cell research has already reached the clinical application stage
in the field of corneal diseases, while in the field of retinal diseases
it is in its infancy.
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Advances in Surgical Procedures
Surgical techniques have evolved hand-in-hand with instrumentation. Notable
newer techniques are the ability to replace one layer of the cornea alone as
in Deep Lamellar Endothelial Keratoplasty (DLEK). Osteo-Odonto Keratoprosthesis
(OOKP) is a technique that involves the use of patient's tooth as a carrier
to implant a synthetic cornea in the eyes of people who have badly damaged cornea
that does not lend itself for routine corneal grafting. Macula which has a very
small area (0.3 mm) is also amenable for surgery with the development of fine
tools. The electronic chip to replace the retina in receiving images is still
in experimental stages, and presently being tried in a small group of disorders.
The writer is Chairman Sankara Nethralaya Chennai
E-mail: drlg@snmail.org
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