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WHAT IS THE RETINA ?
The retina is a nerve layer at the back of the eye that senses light and sends images to the brain. It is commonly called "parda" in north India.
WHAT IS A RETINAL DETACHMENT ?
The retina is attached to the inner back surface of the eye. Detachment is the pulling away of the retina from its normal position. The separation of the retina from the wall of the eye impairs its normal functioning, resulting in blurred vision.
WHAT CAUSES RETINAL DETACHMENT ?
The vitreous is a clear gel that fills most of the space in the eye. It is located in front of the retina. With age, the vitreous pulls away from its attachments to the retina, usually without causing problems. Sometimes the vitreous pulls hard enough to tear the retina. Fluid may then pass through the retinal tear and lift the retina off the wall of the eye.
Risk factors for retinal detachment:
- Myopia or near-sightedness
- Injury to the eye
- Previous retinal detachment in the other eye
- Family history of retinal detachment
- Areas of thin/weak retina
- Complicated cataract surgery
Warning symptoms of retinal detachment:
- Flashes of light
- New, or increase in, floaters [black dots in your vision]
- A gray curtain noticed in the field of vision
HOW IS RETINAL DETACHMENT DIAGNOSED?
The retina is examined with an instrument called the indirect ophthalmoscope after dilating the pupil. Holes and tears are carefully looked for in the periphery of the retina.
TREATMENT:
Retinal tears without detachment - Laser photocoagulation or new PASCAL laser (Ultra-fast, PAINLESS and Precise) or cryotherapy is performed around the tear to seal the retina to the back wall of the eye.
Retinal tears with retinal detachment - Requires surgery as soon as possible to put the retina back in its proper position. The longer the retina stays detached, the less the visual improvement after surgery. Scleral buckle surgery - A flexible silicone band is placed around the eye to counter the force pulling on the retina after removing the fluid under the detached retina. Like a belt holding up a fat man's pants by tighting it at the waist.
Vitrectomy - The vitreous gel pulling the retina is removed from the eye and replaced with a special gas or silicone oil.
Visual recovery:
The more severe the retinal detachment and the longer its duration, the less is the visual improvement after surgery. For this reason it is very important to see an ophthalmologist at the first sign of any trouble. If the condition is left untreated it results in loss of useful vision.
WHAT ARE FLOATERS?
Floaters appear as gray or black specks, lines, or "cobwebs", worms, rings or dots in front of the eyes. As the eyes move, the floaters move too. They do not follow your eye movements precisely, as they usually drift when the eyes start or stop moving.
Floaters are caused by clumping of pre-existing vitreous fibers in the eye or bits of material suspended in the vitreous jelly that fills the back of the eye.
The floaters cast shadows on the light sensitive retina. It is actually the shadow of the floater that you see. Floaters may have a variety of causes, some serious, and some not serious at all. Some floaters are red blood cells or blood clots on the surface of the retina or floating in the vitreous. Such blood cells may occur with some retinal tears but do not necessarily indicate a tear. Occasionally, the vitreous can pull on a blood vessel on the surface of the retina and cause bleeding without causing a tear of the retina. Vascular disorders such as diabetic retinopathy and vein occlusion frequently result in bleeding inside the eye.
Rarely, floaters may be inflammatory in origin. Diseases such as pars planitis and uveitis can cause the formation of clumps of white blood cells (cells that the body produces when there is inflammation).
WHAT ARE FLASHES?
Flashes are sensations of light, when no light is really there. They may appear as many tiny bright lights (like "sparklers") or like flashes of lightning.
Flashes occur when the vitreous jelly pulls on or tears the retina. These flashes usually last for only a second or so, but typically occur repeatedly. They may be more obvious with eye movement or in a dark room.
Some people with migraine headaches may experience a different type of flash. These are usually shimmering, jagged lights that are present constantly for a period of ten-fifteen minutes or so. They typically appear in the center of your field of vision, and progress slowly towards the edges of the visual field. A headache that is commonly throbbing, and on one side of the head, may follow the disappearance of the flashes.
Low blood pressure can cause people to see stars or specks of light, particularly if they change position quickly. An example would be standing quickly from a sitting position or rising quickly after stooping or bending over. Pregnancy related high blood pressure (pre-eclampsia) could also cause light flashes.
ARE FLOATERS AND FLASHES SERIOUS?
Many people have floaters. This happens in over 70% of the population as part of the normal aging process. Floaters that you have had for years, and that show little change, are usually not serious. It is the sudden onset of one or more new floaters that may be serious. The onset of flashes may also be serious.
Anyone with flashes or the sudden onset of a new floater (or floaters) needs a dilated fundus examination (looking at the vitreous and retina with specialized equipment after putting drops to enlarge the pupils).
CAN FLASHES AND FLOATERS CAUSE TOTAL BLINDNESS?
No. Floaters cause only a slight blockage of the vision at worst and are usually not detectable by visual testing unless they are very severe.
Importantly, floaters can be related to retinal detachment or a variety of vascular conditions such as diabetic retinopathy, while flashes can be related to retinal tears (breaks) or detachment. These can result in blindness if not treated.
If one eye develops flashes or floaters will the other develop them as well?
It is very common for the same condition to occur in the second eye. For this reason, and because flashes and floaters are sometimes caused by retinal breaks, both eyes should have a dilated fundus exam as soon as possible when flashes or floaters develop in either eye.
WHAT IS THE VITREOUS?
The vitreous is a jelly-like material that fills most of the space inside the eye. As we age, the vitreous often liquefies and may collapse. This is more likely to occur in eyes that are nearsighted (myopia). It can also occur after injuries to the eye or inflammation in the eye.
WHAT IS THE RETINA?
The retina is a thin sheet of light sensitive nerve tissue that lines the inside of the eye. It is the tissue that turns light into an electrical signal to send to the brain. It can be compared to the film in a camera.
WHAT CAN BE DONE ABOUT MY FLOATERS AND FLASHES?
Your flashes are likely to go away on their own within a few days to weeks. This may be true even if you have a retinal tear or detachment! It is therefore important to be examined by an ophthalmologist even if your flashes go away on their own.
Floaters tend to last longer than flashes. If the floaters are due to blood cells, they will typically disappear.
Most floaters are condensed vitreous collagen fibers and never completely disappear.
Most people learn to ignore them. Floaters, like flashes, may get better on their own even if a retinal tear or detachment is present. Again, you should be examined even if the floaters seem to be going away.
There is no medicine, eye drop, vitamin, herb, or diet that is beneficial to patients with flashes or floaters.
If light flashes are due to a posterior vitreous separation and no retinal breaks (tears) are found on careful examination with the pupil dilated, no treatment is necessary. If the doctor finds tears, laser or occasionally freezing (cryo) treatment is needed.
If you have a retinal tear or detachment, your doctor will talk to you about the treatment.
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