At 55, Satish Chandra, a myopic from early childhood, started seeing flash-es of light in his vision. A few days later, the flashes were replaced by black spots swimming before his vision. A visit to an ophthalmologist confirmed that there was a problem. His retina had developed a tear in the periphery, which, if not treated immediately, could lead to retinal detachment and a consequent loss of vision.How did the tear occur? Says Vitro Retinal Surgeon Cyrus M. Shroff, who practices at Kailash Colony, ``The retina tends to become thin with age, which probably leads to the formation of holes. I say probably because there is no scientific proof of this but the degenerative changes in the retina are the only logical explanation to its tearing''. The other more common reason can be shrinkage of the vitreous - the fluid which fills the cavity of the eye and is attached to the retina. As a person ages, the vitreous, which is initially gel-like, begins to liquefy and small pockets of this liquefied fluid form within the gel. As the eyeball moves, so does the liquefied vitreous inside the vitreous cavity and exerts a pull on the retina.Gradually, as the vitreous shrinks, it may pull a piece of the retina away with it, causing a tear or a hole in it. The brain interprets this pulling as flashes of light. This is followed by the vitreous becoming condensed and forming strands, which appear to the patient as spots, circles, or fine threads in the vision. These seem to float and are, therefore, called floaters.``Though some shrinkage of the vitreous body occurs normally with aging and does not cause any damage, certain reasons like acute myopia, inflammation or injury may lead to excessive shrinkage. Sometimes, a foreign body like cracker or a piece of metal may cause the detachment,'' says Mahipal S. Sachdev, Consultant, Indraprastha Apollo. Once a tear or a hole is formed, watery fluid from the vitreous space may pass through it and flow between the retina and the back of the eye, causing what is called ``retinal detachment''.Vision is lost wherever the retina gets detached. Since most tears begin at the periphery of the retina, the retinal detachment first causes the loss of side or peripheral vision. The patient may notice a dark shadow, or a veil, falling in a particular angle of vision. ``If left unattended, the whole retina may detach,'' says Sachdev. The vitreous pulling at the retina may cause bigger tears, called giant retinal tears. Sometimes the tear may be so large that the retina may fold itself over. This is a more serious problem.Apart from aging, retinal detachment may be caused by physical trauma like a strong physical blow in the eye. In rare cases, this condition is hereditary and may occur in infants and children. Patients suffering from thinning of the retina (called a lattice degeneration) or other degenerative changes are also at increased risk. Individuals who have had cataract surgery have about 2 per cent chances of developing it.Early detection of the tear formation prevents more damage. The damage can be controlled by simply sealing the hole or the tear by laser or cryopathy. This prevents the fluid from the vitreous to flow and detach the retina from the back wall of the eye. ``In cases where the retinal detachment has already started, however, the retinal has to be simultaneously pushed back. For this, we may have to resort to surgery,'' says Shroff.It can be done either by scleral buckling, in which a surgeon sews a piece of silicon band or sponge to the outside wall of the eye over the site of the retinal tear. This buckle supports the area till the laser or the cryopathy helps seal the tear. Another way is to inject an air bubble inside the vitreous cavity. After this process - called pneumatic retinoplexy - the patient has to keep his head in a specific position so that the bubble pushes the detached retina against the wall of the eye. The gas bubble disappears on its own in a while,'' explains Shroff.Occasionally, the condition is so complicated that it cannot be treated with scleral buckling surgery or pneumatic retinoplexy. In such cases, vitreous surgery is performed to reattach the retina. Here, the vitreous is removed through surgery and the eye is filled with a clear fluid compatible with the eye. Surface tension caused by the fluid or the gas pushes the retina back into position. Over a period of time, the fluid or air is absorbed by the eye and replaced by its own fluids. The lack of viterous does not affect the eye.Though there is no way to prevent retinal detachment. All that the experts have to say is, ``A timely check-up can make the difference between your losing or keeping your vision''.
