Blind World Magazine

Retinal degeneration: don't lose hope.




Dr Mahipal S. Sachdev,
The Tribune - Chandigarh,India.
Tuesday, September 05, 2006.




Every time a patient of advanced retinal degeneration, age-related macular degeneration or retinitis pigmentosa goes to an ophthalmologist, the most common answer he gets to hear is that there is nothing that we can do.


It is disheartening to know that one has no hope. Not only the patient but the doctor is also extremely disappointed to tell his patient that no treatment can be offered.


This is the reality status for now as far as the treatment of these diseases is concerned. But do we lose all hope? The answer would be a big NO!


Is there anything which can be offered to these patients? The answer may lie in using certain artificial devices that can be implanted onto neural retina. Using artificial devices means treatment of extreme vision impairment has come of reality during the past few decades.


What happens in these diseases that nothing can be done?


A variety of disease processes can affect the retina and/or the optic nerve. These disease processes may selectively damage certain parts of the retina or optic nerve.


The retina is the innermost part of the eye, which acts like the film of a camera. It is made up of cells known as rods and cones. These cells once destroyed cannot be regenerated, that is why these retinal diseases are potentially blinding.


Retina is made up of outer and inner layers. Diseases like age-related macular degeneration, pathologic myopia and retinitis pigmentosa involve the outer layer. Although these outer cells are lost, the inner retina is preserved and may help in designing retinal prosthesis (artificial retina)


Retinitis pigmentosa and advanced cases of age-related macular degeneration are incurable diseases that result in profound vision loss due to the degeneration of these cells.


Currently, there is no real treatment available for these blinding disorders that stem from the degeneration of retinal cells and affect at least 50 million individuals worldwide. There is no effective treatment for these patients with advanced ARMD, retinitis pigmentosa and associated diseases. The good news, however, is that studies are being carried out for the potential of the retinal cell transplantation to decrease the progression of these blinding diseases


A few surgical modalities like macular translocation and displacement of blood in certain cases of age-related macular degeneration have shown promising results. The aim of these surgeries is to utilise the function of the living residual cells. Experiments are being carried out to introduce such devices as cause magnification or surgical implantation of electronic devices.


What does the future hold?


With advances in microchip technology, surgical treatment of low vision is now showing promising results.


The artificial silicon retina (ASR) microchip which can be implanted onto retina offers an option to totally blind people in the future. This chip can take up the function of dying or dead cells. Certain devices for optic nerve are also being studied. But there is need to prove long-term safety for both human subject and the electronic implant.


The evolution of surgical methods to treat patients with low vision is leading to promising outcomes. Retinal surgery to provide telescopic magnification in low vision patients and retinal microchip implants, where no retinal function exists, are now a reality. Although still experimental, they provide a ray of hope for these patients Research is being carried out to create an implantable medical device that provides useful vision to patients who are left with no alternatives. These implants are still in their experimental stages.


Stem cells also form a significant potential source for ocular repair. The procurement of these donor cells is still a problem.


Stay clear of certain misconceptions!


l Certain claims are being made about the treatment of these diseases by acupuncture and other modalities. Definitive scientific proof is still lacking for the efficacy of these treatment modalities. As these patients are desperate to regain some amount of vision, they are easily taken for a ride by such claims.


l For a layman, eye transplant means the whole of the eye can be replaced. Actually, when we talk about eye transplant we only mean the anteriormost part of the eye, which is the cornea and can be replaced. It does not indicate that an old eye is replaced and a new one put!


The writer is Chairman and Medical Director, Centre for Sight, New Delhi. E-mail: msachdev@bol.net.in



http://www.tribuneindia.com/2006/20060906/health.htm#1




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