Information Bank

What is retina?

Retina is the sensitive part of the eye which sees and conveys images to brain for analysis. The eye can be compared with a camera. The cornea and lens together act as focusing mechanism to focus just as there is lens for the camera. The retina is akin to film of camera which records the images.

What is diabetic retinopathy and how it happens?

Diabetic retinopathy is the complication of diabetes that affects the retina. Diabetes primarily affects the blood vessels all over body and same happens in the retina as well. Retina has tiny blood vessels that are easy to damage. Having high blood glucose for a long time can damage these tiny blood vessels. It causes blood vessels to weaken, bulge and leak fluid into surrounding tissue, causing swelling – a condition called macular edema. Some blood vessels then become clogged and do not let enough blood through. Because the blood vessels are no longer delivering the proper amount of nutrients to the retina, more vessels grow on the retina in an attempt to restore blood flow. These new blood vessels are also weak and inadequate, making them prone to leakage and breaking. They can bleed into the eye and block vision. After some time, these vessels may contract and pull the retina along with them causing a tractional retinal detachment.

This is a serious eye disease and may lead to total blindness if not treated adequately in time.

Who’s at the most risk for diabetic retinopathy?

All diabetics are at risk for developing diabetic retinopathy. Fluctuating and uncontrolled blood sugar levels lead to an increased risk of this disease. Long duration of the diabetes also increase risk. Most people don’t develop diabetic retinopathy until they’ve had diabetes for at least 10 years. High blood pressure, high cholesterol, and pregnancy can all place a patient at greater risk of suffering from the eye disease. Diabetics can minimize their risk by controlling their blood sugar and by having their eyes examined by a qualified ophthalmologist at least once a year.

Is there any way to prevent diabetic retinopathy?

There is no absolute way to prevent it. However, keeping your blood sugar at an even level can help prevent or minimize diabetic retinopathy. If you have high blood pressure, keeping that under control is helpful as well. Even controlled diabetes can lead to diabetic retinopathy, so you should have your eyes examined once a year; that way, your doctor can begin treating any retinal damage as soon as possible. You can prevent vision threatening complications if treated early enough.

What are the symptoms of diabetic retinopathy?

In the early stages, there may not be any symptoms of diabetic retinopathy. That is why it is imperative that diabetics have their eyes examined by an ophthalmologist annually.

Later symptoms of diabetic retinopathy include cloudy vision and blurred central vision. You may develop blind spots or floaters also.

Why there is reduction in vision in diabetic retinopathy?

Reduction in vision occurs due to either a macular edema/ischemia or due to complications of proliferative retinopathy i.e. vitreous hemorrhage & tractional retinal detachment.

How is diabetic retinopathy diagnosed?

Early signs of diabetic retinopathy can be detected with a routine eye exam. Getting an early diabetic retinopathy diagnosis will help delay progression of the disease and allow you to seek effective treatment sooner. Examination requires pupil dilation which is done by placing special eye drops into the patient’s eye. These drops dilate the pupil, and make it wide; allowing the ophthalmologist to check the retina.

Why a fluorescein angiography is required?

Fluorescein angiography is an examination in which a dye is injected intravenously and as the dye travels through the blood-stream & passes into the blood vessels of the retina, photographs of the retina are taken rapidly. It reveals the status of blood flow in the retina. It shows the leaking vessels so that they can be treated and closed. It helps to see the clogged vessels and extent of the clogging which is not seen by naked eye. It also shows formation of abnormal new vessels on retina. It can also shows the blood supply to centre of retina called macula, to determine if that is causing visual loss. All this information is required for further treatment.

What are the different types of diabetic retinopathy?

Diabetic retinopathy is classified as either nonproliferative (background) or proliferative. Nonproliferative retinopathy is the early stage, where small retinal blood vessels break and leak.

In proliferative retinopathy, new blood vessels grow abnormally within the retina. This new growth later on contract causing tractional retinal detachment, which can lead to vision loss. The new blood vessels may also grow or bleed into the vitreous humor, the transparent gel filling the eyeball in front of the retina. After some time, these vessels may contract and pull the retina along with them causing a tractional retinal detachment leading to loss of vision. Proliferative retinopathy is much more serious than the nonproliferative form and can lead to total blindness.

What is the treatment?

The treatment depends on what type of retinopathy one is having and whether macular edema is present or not. There are 3 types of treatment laser photocoagulation, intraocular injections and vitrectomy surgery.

How is the laser done for diabetic retinopathy?

Laser is usually done to close the leaking vessels causing macular edema or to close the abnormal blood vessels. Usually the laser treatment is divided in 3-4 parts to minimize side effects. Each sitting is done 3-7 days apart.

What are the chances of success? How much vision will I regain?

The aim of the laser treatment is to preserve and maintain the current level of vision. It is usually successful in preventing further visual loss. It is not intended to improve the vision. However, in some cases it may improve vision, but that is not predictable.

How long can I wait for the laser?

The laser if required should be done as soon as possible to prevent further damage to retina.

How is the laser done?

The laser is usually done by putting eye drops in eye. Only in few cases a local anaesthesia with injection is required. It is done sitting on the machine or sometimes lying down. Laser photo coagulation is an outpatient procedure. You will be able to go home afterward.

How long will it take?

The laser itself takes around 15 to 20 minutes for each eye.

Does it pain during laser?

It usually does not pain during the laser. However, a feeling of discomfort or a pricking sensation can be felt by some. Any pain, if felt, is usually tolerable. In rare cases if pain sensitivity is high, injection can be given to numb the pain.

What are the precautions after the laser?

After laser, vision is temporarily reduced for few minutes after which it improves rapidly. However, for about 24 hours after your procedure, your vision may be hazy or blurry. You have to take some tablets and eye drops prescribed by doctors. You will be able to go home afterward, but you will need to arrange for transportation, as you will not be able to drive immediately following surgery. You can carry about your normal routine. But avoid lifting weights or heavy objects, and strenuous exercise. Heavy cough and constipation if present should be treated.

What are possible complications / side effects?

Because laser photocoagulation involves tiny burns to seal the capillaries, small spots may appear in your field of vision after the procedure. These small spots generally fade and disappear with time. If your vision was blurry prior to the laser photocoagulation procedure, you may not completely recover clear vision. Usually, you will regain your vision to the pre-treatment level.

Sometimes you may get difficulty in seeing in dim light or in night. Your vision may remain depressed for a while but will recover over next 2-3 months.

Will this recur again? / Will I need another laser?

The laser is usually successful in closing abnormal blood vessels in almost 95-97% patients. However, if the sugar levels remain uncontrolled or fluctuating this may recur in some patients. Failure to control blood pressure may also be responsible for recurrence. In this case an additional laser treatment will be required. Sometimes intraocular injections may have to be given.

As the diabetes is a continuous disease, so are its effects on retina. That’s why it is imperative to have routine examinations of retina even after laser. It helps in detecting and treating any adverse events, if any.

Is there any treatment without laser?

No. Currently there is no effective treatment for proliferative disease which leads to long term stabilization of vision.

Can this be cured with glasses or with lens inside eye?

No. This cannot be cured with glasses or medicines. Putting lens inside eye is treatment for cataract and will not stop bleeding or leaking blood vessels in your retina which is the cause of loss of vision in your case. However, if a cataract is present simultaneously, IOL can be put before with or after laser depending on the stage of cataract.

What will happen if I don’t get laser done?

Failure to treat will lead to growth of these abnormal vessels. These may bleed from time to time. They also can contract and pull the retina away from the back wall of eye leading to tractional detachment. At this stage only a vitrectomy surgery can salvage remaining vision. However, if vitrectomy is not done promptly, usually only an ambulatory vision is regained. After few years the eye will permanently become blind.

Will this affect my other eye?

Yes. As diabetes affects all your body, naturally other eye will also be affected. Usually it affects both eyes simultaneously, but frequently it is more advanced in one of the eyes.

I have been advised an injection inside eye. How it will be useful?

An injection is advised usually to treat the macular edema, present along with. Either a triamcinolone or Avastin (Bevacizumab) is injected inside the eye. The choice of drug depends on the condition of eye.

Alternately, Avastin (Bevacizumab) is advised to rapidly dry out the abnormal vessels. This is usually required if there are blood vessels growing over iris and blocking the normal channels to drain the fluid inside the eye.

What are the treatment options for diabetic macular edema?

Treatment of diabetic edema is by either a laser or an injection inside eye or combination of both.

How is laser done for it?

Laser is usually done to close the leaking vessels causing macular edema. Sometimes 2 or 3 sessions of laser are required at an interval of 2-4 months. The laser is usually done by putting eye drops in eye. It is done sitting on the machine. Laser photocoagulation is an outpatient procedure. You will be able to go home afterward.

What are possible complications / side effects?

Because laser photocoagulation involves tiny burns to seal the capillaries, small spots may appear in your field of vision after the procedure. These small spots generally fade and disappear with time. If your vision was blurry prior to the laser photocoagulation procedure, you may not completely recover clear vision.

What injections are to be given inside eye?

There are two injections triamcinolone and Avastin (Bevacizumab) that are given inside the eye. The choice of drug depends on the condition of eye. The injections need to be given in an operating theatre to minimize the risk of infection. They are given only by putting aneasthetic drops. Usually no aneasthetic injections are required. There may be minimal pain but is usually tolerable.

How do these injections work?

These injections act on the leaking vessels in macula and reduce or stop their leakage. This leads to reduction in swelling in macular area which may lead to increase in vision. Avastin in addition rapidly closes the new blood vessels on retina giving a double advantage.

What are possible complications of injection?

As with any injection, chances of infection inside eye are there. However, all due precautions are taken to minimize this complications. Triamcinolone may sometimes lead to increase in eye pressure in 2-3 months’ time. This can usually be controlled by eye drops; very rarely a surgery is required.

How much vision will I regain?

The aim of the laser treatment is to preserve and maintain the current level of vision. It is usually successful in preventing further visual loss. It is not intended to improve the vision. However, in some cases it may improve vision. Injection inside eye may improve vision in many cases, but not to the normal level.

Why a surgery is required?

A surgery is required if there is bleeding inside the eye (vitreous hemorrhage) that is not getting absorbed. A tractional retinal detachment, if present near the macula (centre of retina) also requires urgent surgical treatment to prevent further visual loss. A vitreous hemorrhage along with tractional retinal detachment, as seen on ultrasound scan, also requires urgent surgery.

How is the surgery done?

During the surgery, the gel like structure inside eye, called vitreous, is removed. Any bleeding present is also removed. Any scars or membranes formed by the contracting blood vessels are also removed to settle the tractional detachment. Laser is applied to retina, if not done previously or if inadequate. Lastly the eye is filled with a gas or silicon oil.

The surgery can be done either under a local or a general anaesthesia depending on the surgeon and patient preference. All of these surgical techniques are done microscopically. We want to reassure you that your surgeon does not take your eye out of its socket to operate on it. This is simply impossible.

How long will it take?

The surgery itself takes around 1½ to 3 hours to complete depending on the conditions and complicating factors inside eye.

When would I see after surgery?

It usually takes 1 to 2 months for visual recovery. The vision recovery may continue till 1 year, at the end of which no further improvement is possible.

What are possible complications?

As with any surgery, complications can happen both during surgery and after surgery. It includes intraocular haemorrhage, retinal breaks and rarely infection inside eye. If silicon oil is used in repair; it may cause cataract, glaucoma or damage to cornea. If silicon oil is used then it is necessary to have regular re-examinations and removal of oil at the earliest as deemed fit by the vitreo-retinal surgeon.

Will this recur again? / Will I need another surgery?

The tractional detachments will usually not recur. However, in some cases, there may be recurrent bleeding (vitreous haemorrhage) which may get absorbed on its own or might require a re-surgery.

How much vision would I regain?

The amount of vision regained depends on the degree of damage to the retina by diabetic retinopathy. If there is only a vitreous haemorrhage, the visual recovery can be fair. However in cases of tractional retinal detachments only an ambulatory vision may be regained. Ask your surgeon regarding the expected outcome in your case.

Why should I get the surgery done if I am not going to get full normal vision back?

Even though you may not get full normal vision, surgery will most probably improve vision from its current level. Even if you don’t get improvement in vision, the surgery is usually effective in preventing further damage to the retina and further vision loss, failing which you may lose all your vision.

What is retina?

Retina is the sensitive part of the eye which sees and conveys images to brain for analysis. The eye can be compared with a camera. The cornea and lens together act as focusing mechanism to focus just as there is lens for the camera. The retina is akin to film of camera which records the images.

What is retinal detachment and how it happens?

A retinal detachment is occurs when the retina separates from the back wall of the eye. This typically happens when liquefied vitreous fluid (fluid inside the eye) passes through a small tear in the retina and collects behind the retina. This collection of fluid causes a lifting action and markedly disturbs the vision. Frequently, detachments begin with loss of peripheral vision and patients may notice a dark shadow, or a veil, coming from one side, above or below. Left untreated, in most cases, after a retinal detachment starts, the entire retina will eventually detach and all useful vision in that eye will be lost.

This is a serious eye disease and may lead to total blindness if not treated adequately in time.

Who gets retinal detachments?

Some people are at increased risk of developing retinal detachments. The high risk group includes those with a high degree of nearsightedness, a family history of retinal detachment, or those who have previously experienced a retinal detachment. Patients that have had cataract surgery also experience about a 1-2 % chance of developing a retinal detachment.

What is the treatment?

The treatment is a surgery in most of the cases. The surgery can be either a retinal surgery or a vitreous surgery depending on the severity and duration of the detachment.

Retinal Surgery
This involves scleral buckling – where a sponge or length of silicon plastic is placed on the outside of the eye and sewn in place (the scleral buckle is very small and not visible after surgery), pushing the sclera toward the tear in the retina and allowing it to seal.

Vitreous Surgery
If the retinal detachment is too severe for scleral buckling, vitreous surgery to reattach the retina may be necessary. Here, the surgeon removes the vitreous entirely, replacing it with a gas or silicon oil. Membranes if any are also removed. A scleral buckle, if required, can be additionally used. Over time, the gas is absorbed, and replace with the eye’s own fluid. Lack of vitreous does not affect the patient’s vision. Silicon oil if used needs to be removed later when surgeon thinks its safe enough to remove.

What are the chances of success? How much vision will I regain?

The success of these surgical techniques depends upon several factors including the size and location of the damaged area of the retina, the length of time that elapses between the onset of the tear or detachment and the surgery to repair the damage, and whether or not other complicating factors are present. Many persons who have undergone retinal reattachment surgery regain all of their previous vision, while some regain only functional vision. Even in these latter instances, the treatment is usually effective in preventing further damage to the retina and more vision loss.

How long can I wait for the surgery?

This surgery is an emergency procedure and should be performed as soon as possible. The chances of successfully restoring vision are dramatically improved when intervention occurs as soon as possible following the onset of symptoms. With each passing day of untreated detachment, retina further loses its ability to function.

How is the surgery done?

The surgery can be done either under a local or a general anesthesia depending on the surgeon and patient preference. All of these surgical techniques are done microscopically. We want to reassure you that your surgeon does not take your eye out of its socket to operate on it. This is simply impossible.

How long will it take?

The surgery itself takes around 1½ to 3 hours to complete depending on the conditions and complicating factors inside eye.

When would I see after surgery?

It usually takes 1 to 2 months for visual recovery. The vision recovery may continue till 1 year, at the end of which no further improvement is possible.

What are possible complications?

As with any surgery, complications can happen both during surgery and after surgery. It includes intraocular hemorrhage, muscle damage, ocular perforation and rarely infection inside eye. If silicon oil is used in repair; it may cause cataract, glaucoma or damage to cornea.

Will this recur again? / Will I need another surgery?

The surgery is usually successful in attaching retina in 80-85% cases. Remaining 10-15% patients may require a second surgery. However, this depends on many factors. You can ask your doctor regarding this in your individual case.

Is there any treatment without surgery?

Very small detachments of the retina can be surrounded by laser treatment, just like retinal tears, to help limit their spread. Another procedure called Pneumatic Retinopexy, which is less traumatic than surgery, can be done for selected cases. Here, the surgeon injects a gas bubble inside the vitreous cavity. The bubble pushes the retina against the wall of the eye, allowing the tear to seal against the eye wall.

However, this type of treatment can be done only in some selected patients only and requires patient to be seated or lie in a specified position for 12-18 hours in a day. Failure to maintain position will result in failure of treatment. If this treatment fails to reattach the retina, a second surgery in form of scleral buckling or vitrectomy will be necessary.

Can this be cured with glasses or with lens inside eye?

No. This cannot be cured with glasses or medicines. Putting lens inside eye is treatment for cataract and will not attach retina which is the cause of loss of vision in your case. However, if a cataract is present simultaneously, IOL can be put along with or after surgery for retinal detachment depending on stage of cataract.

What will happen if I don’t treat?

The detachment of the retina from the back wall of the eye causes it to be removed from its blood supply and therefore its source of nutrition. An untreated detachment will cause the retina to degenerate and lose its ability to function, permanently in some cases. After a few years, it will totally lose its ability and surgery will not be effective at that stage.

Will this affect my other eye?

No. This will not affect the other eye. However the other eye is at a higher risk of detachment than normal. The other eye should be examined and treatment in form of laser or freezing (cryo) should be done if necessary.

Why should I get the surgery done if I am not going to get full normal vision back?

This is a serious eye disease and may result in total blindness. There is no other treatment. Even though you may not see as well as you were before detachment, surgery will most probably improve vision from its current level. Even if you don’t get 100% recovery of function, the treatment is usually effective in preventing further damage to the retina and more vision loss, failing which you may lose all your vision.

What is PVR?

PVR is proliferative vitreo-retinopathy; a term used to describe the formation of membranes over or behind detached retina and in vitreous cavity. These membranes, which are essentially scar tissues, exert traction on the retina and may result in recurrences of retinal detachment, even after an initially successful retinal detachment procedure. PVR may be associated with spontaneous reopening of otherwise successfully treated retinal breaks and may even cause the development of new retinal breaks. Finally, PVR may be associated with severe distortion and “stiffness” of the retina, as a result of the contracting membranes. This aspect of the condition not infrequently results in disappointing visual results, despite the very best of management.

What is treatment of PVR retinal detachment?

Treatment is essentially surgical and requires vitrectomy along with placement of silicon ring around the eye called encirclage. During vitrectomy, the vitreous humor is removed and the vitreo-retinal surgeon then performs a membrane peeling procedure, in which the contracting membranes on the retinal surface are carefully peeled away from the retinal surface. The surgeon will also typically treat the retina surrounding any retinal tears or holes with laser to help maintain closure of the retinal breaks.

Following the vitrectomy procedure, the surgeon usually instills special gases or silicon oil into the eye to help flatten the retina and keep it reattached to the outer wall of the eye. If gases are instilled in the eye, head positioning following surgery (for days or weeks) may be necessary to help keep the retina attached. If silicone oil is placed in the eye to help maintain the retina in the attached position, it must eventually be removed from the eye in the majority of cases after 3-6 months depending on status of retina.

What to expect after surgery for PVR?

It is important to realize that recovery of vision after surgery for PVR may take many months. About 50% of patients will regain some useful vision in the affected eye. The level of vision regained, however, is often referred to as “ambulatory vision,” indicating vision good enough to see large objects at a close range. The likelihood of regaining vision well enough to read is quite low.