Retina

The eye is like a camera with a lens in front and a film (retina) at the back. The retina is located approximately two centimeters behind your pupil. It is shaped like a small cup. The retina converts the ocular image into a signal that is sent to the brain. The central part of the retina, called the macula, is used for straight-ahead vision and what is in your direct line of sight. 

A healthy macula is crucial for tasks involving fine vision such as reading, recognizing faces and distinguishing things. The area surrounding the macula helps in mobility and in seeing from the 'corner' of the eye, though it is not useful for fine work. The retina is connected to the brain by the optic nerve. Blood is supplied to the retina and the optic nerve by blood vessels that maintain the health of these tissues. In front of the retina is the vitreous cavity, which is filled with a gel-like substance, called the vitreous.

Diseases of the retina, the vitreous, and the optic nerve can cause serious vision problems. Fortunately, most of them can now be managed satisfactorily with modern methods of diagnosis and treatment. 

This link will help you understand the treatment of diseases of the retina and the vitreous. Remember, early diagnosis and prompt and appropriate treatment can result in a better outcome.

If you have any problems or questions:
Call the Retina specialist at L V Prasad Eye Institute or call (040) 3061 2107.

Retinopathy of Prematurity

Why should I worry about the eyes of a premature baby?
The inside of the eye, the retina is not fully developed in premature babies. Abnormal blood vessels can develop in such a retina. These abnormal blood vessels can cause internal bleeding and even retinal detachment. This is called Retinopathy of Prematurity (ROP). This condition results in low vision or blindness - both of which are irreversible.

How can we detect ROP?
A trained ophthalmologist can detect ROP by dilating the pupils of the eye using eye drops. An indirect ophthalmoscope is used to scan the entire retina to detect ROP and gauge the state of retinal maturity.

Do all babies need a retinal examination for ROP?
Babies with a birth weight of less than 1700 grams or those born in under 35 weeks of pregnancy are most likely to have ROP. 

Pre-term babies who have had problems after birth such as lack of Oxygen, infections, blood transfusions breathing trouble, etc., are also vulnerable.

Is it too late for my baby's eyes?
Follow the "Day-30" strategy. The retinal examination should be completed before "day-30" of the life of a premature baby. It should preferably be done earlier (at 2-3 weeks of birth) in very low weight babies (<1200 grams birth weight).

What is the treatment for ROP?
ROP is treated with Laser rays or a freezing treatment (Cryopexy). The treatment helps stop further growth of abnormal vessels thus preventing vision loss.

How often should the retina be examined?
ROP can progress in 7-14 days and therefore, needs a close follow-up till the retina matures.

When should we treat ROP?
ROP needs to be treated as soon as it reaches a critical stage called Threshold ROP. There is 50% or greater risk of vision loss if left untreated after this. Time is crucial!

After treatment
If treated in time, the child is expected to have reasonably good vision. All premature babies need regular eye examinations till they start going to school.

They may need glasses or treatment for lazy eyes/ cross-eyes and sometimes, for cataract, glaucoma and retinal detachment.

Faculty Details

Laser Treatment of the Retina

Laser treatment of the retina
A laser is a pure, high-intensity beam of light energy. The laser light can be precisely focused onto the retina, selectively treating the desired area while leaving the surrounding tissues untouched. The absorbed energy creates a microscopic spot to destroy lesions or weld tissues together.

Laser surgery is usually painless; at the most it may cause temporary discomfort. It is usually performed in the operating room while the patient is awake and comfortable. In rare cases, anesthesia is given those patients who cannot tolerate the discomfort or to children to keep them still during treatment. The entire procedure lasts 10 to 30 minutes.

Who requires laser treatment?
Lasers are commonly used to treat the following eye conditions:

Diabetic Retinopathy
The retinal blood vessels are like pipes, bringing blood into and taking it out of the back of the eye. In diabetes, however, the vessels may leak, causing the retina to swell and not work properly. When the swelling involves the central area of retina vision may be affected. (This is known as diabetic macular edema.)

Laser treatment can seal the leaks, thereby preventing further vision loss. In some patients new retinal blood vessels may grow, which will replace some of those that have closed due to diabetes. (This is known as proliferative diabetic retinopathy). This new retinal blood vessel, unlike the normal blood vessel, has a tendency to bleed inside the eye, resulting in decreased vision. Laser treatment can often prevent severe vision loss by making these new vessels regress.

Retinal Vein Occlusion 
The small blood vessels that drain the blood from the retina (retinal veins) can sometimes get blocked (retinal vein occlusion). This is more common in patients with diabetes or high blood pressure. A retinal vein occlusion can cause the retina to swell with fluid and blood, blurring central and peripheral vision. At other times, new blood vessels may grow and cause pain as well as very high pressure inside the eye (neovascular glaucoma).

Laser treatment can help reduce this swelling or cause the new blood vessels to disappear.

Age Related Macular Degeneration (AMD)
With age, some people may develop changes in the macula, the portion of the retina responsible for our central reading vision. Most people develop the dry type of AMD, which usually causes gradual vision loss. The more severe or wet type causes the macula to swell with fluid and blood. Symptoms of wet macular degeneration include painless, blurred and distorted vision. Urgent laser surgery can sometimes prevent or delay vision loss in patients with wet AMD. While the off central wet AMD patients benefit from thermal laser treatment, those with central vision problems need a prior injection of Visudyne. This is known as photodynamic therapy.

Retinal Breaks and Retinal Detachment
The retina lines the back of the eye like a wallpaper. Retinal tears or rips can occur as part of an aging phenomenon, or following an intraocular surgery or eye injury. When a retinal tear develops, patients often see cobweb-like floaters or light flashes. The liquid that normally fills the central portion of the eye (the vitreous) can leak beneath the tear, lifting the retina away from the eye wall. This is called a retinal detachment, which if left untreated can cause blindness. Often laser surgery around retinal tears before the fluid accumulates enables surgeons to weld the retina to the underlying eye wall. This can prevent or limit retinal detachment.

Central Serous Chorioretinopathy (CSCR)
Central Serous Chorioretinopathy consists of one or more 'blisters' of fluid (serous detachment) beneath the macula. It can cause reduction and distortion of vision, abnormal color vision, central scotoma, and temporary hyperopia or far-sightedness. Although the vast majority of cases resolve on their own, laser photocoagulation is sometimes necessary for persistent lesions and in those patients who require early visual rehabilitation.

Ocular Tumors
Some patients may have non-cancerous leaking vascular tumors that can cause the retina to swell and not function properly. Laser surgery can destroy some of these tumors and make the swelling go away.

How do I know that I require laser treatment?
With retinal diseases your eye will almost always look and feel normal, even when there is bleeding and leakage in the back of the eye. Your vision may also be normal for a while despite the presence of potentially blinding eye problems.

The only way to find out whether you need laser surgery is to have careful, dilated retinal examinations at regular intervals, often followed by a special test (called fluorescein angiography if advised by the retinal specialist), to evaluate the eye's circulation.

After laser surgery
There are virtually no restrictions following retinal laser surgery, but you would need to relax on the day of the treatment. Most patients find they can go back to their routine a day later. Invariably the doctor will advise you not to lift heavy weights for a few weeks. In some cases the doctor may advise patients to stay at home for several days. You will be required to come again for a follow-up examination in a couple of weeks up to a couple of months.

Most patients notice no changes in vision following their laser surgery, although there may be some temporary blurring for several weeks or even months. In addition, depending on the condition being treated, some patients may notice a permanent blind spot or decrease in peripheral and night vision.

Is one session of laser treatment enough?
The number of sessions required by a patient depends on the disease for which the laser treatment is done. It takes usually several weeks to months for surgeons to decide whether the treatment has been successful. Many patients require more than one session of treatment to control their problem and prevent further loss of vision.

Freezing or Cryo Treatment of the Retina

What is cryosurgery?
'Cryo' means extremely cold or freezing. This operation employs a delicate instrument that freezes small spots which are transformed into pinpoint scars that strengthen the retina. The temperature required for cryosurgery is approximately minus 70 degrees centigrade.

What are the do's and don'ts after cryosurgery?
Generally patients can return to their normal routine the following day. But they are advised to relax on the day of surgery. In cases where there has been a tearing of the retina, the surgeon may ask patients to limit their activities for at least ten days. The restrictions may include the following:

  • If an eye pad was used after the cryosurgery, it should be removed after one day of use.
  • Do not bend over so that your head is below your waist.
  • Do not lift anything that weighs more than five kilograms.
  • Avoid rubbing the affected eye.
  • Avoid strenuous activities: you may cook or wash dishes, but no housework that involves bending or lifting weights. 
  • You may watch television or read.
  • Alcoholic beverages should be avoided.
  • No sexual intercourse.
  • No automobile trips except to the doctor's office.

What are the effects of cryosurgery? 
Temporary side effects include blurred vision, redness of the eye, mild pain, watering, double vision, swelling of eyelids or a dilated pupil. These side effects usually clear up within a few weeks. Most patients respond favourably to this operation, but a small percent of patients may not.

What are the possible complications?
All surgery has some possible complications but fortunately, the occurrence of such problems with cryosurgery is infrequent. At least 99% patients have no complications. The complications that may occur include bleeding within the eye or retinal detachment. There is the very rare possibility that all vision might be lost.

Diabetic Disease of the Retina

How does diabetes affect the retina?
Most persons suffering from diabetes develop changes in the retina over a period of time. This is caused by damage to the small blood vessels (or capillaries) in the retina.

What can I do to limit the diabetic damage to my retina?
You should consult the doctor treating you for diabetes regularly and follow all instructions regarding diet and medication. It is a fact that only strict control of blood sugar will help minimize damage to the retina. Frequent examination of the retina after full dilation of the pupil can help detect retinopathy early, leading to better treatment outcomes. This retinal examination should be done periodically even if your vision is clear.

Can diabetes affect other parts of the eye?
Retinal changes are the major problem, but at times diabetes can also cause a rise in eye pressure (glaucoma), clouding of the lens (cataract), and weakness of the optic nerve or eye muscle. Cataracts often occur at a younger age in diabetic patients. Glaucoma can cause damage to the optic nerve. In fact diabetes is one of the several possible causes of glaucoma.

Damage to the small vessels of the optic nerve can affect vision, and weakness of the eye muscles may cause double vision. A diabetic is also more likely to develop sudden vision loss due to occlusion of the retinal vessels (branch or central retinal vein occlusion), bleeding in the vitreous cavity, detachment of the retina, or infections of the cornea and vitreous.

How does diabetic retinal disease (diabetic retinopathy) affect the vision? 
Swelling (edema) in the central part of the retina (macular edema) can cause blurring of fine vision. Fragile new blood vessel sprouts may break and bleed into the interior of the eyeball, causing blurring of the entire field of vision. In the early stages of the disease the vision remains good therefore, the disease may escape notice. That is why it is essential to have regular retinal examinations if you know that you have diabetes.

How can this disease be treated?
Swelling of the central part of the retina may be controlled with limited laser treatments. Sometimes one laser session will suffice, though some patients require several sessions. Abnormal blood vessel sprouts require extensive laser treatment involving 2,000 to 3,000 laser spots, i.e., three or more laser sessions. More acute problems with severe bleeding or retinal detachment require surgery such as scleral buckling or vitrectomy or both.

What are the results of the treatment?
Limited laser treatment in the central zone of the retina is designed to reduce the amount of future visual loss, but the lost vision cannot be restored.

Extensive laser treatment for fragile blood vessel sprouts usually prevents a large bleed within the eye, thereby preventing major loss of vision.

Vision loss from severe bleeding in the eye or retinal detachment can usually be improved with surgery, but some patients may not respond to the treatment.

Because we have as yet no cure for diabetes, it may continue to damage the retina even after laser treatment or even if the blood sugar level is controlled. Patients with diabetic retinopathy need life-long regular follow-ups after treatment.

What are the complications of the treatment?
Most patients do not have any complications but occasionally, laser treatment may cause temporary pain or blurred vision since the effect of the treatment is seen only 4-6 weeks later. Mild or severe haemorrhage or retinal detachment can also occur. Such complications are occasionally seen after major eye operations and may very rarely lead to loss of complete vision.

Photography of the Retina with Dye

Fluorescein Angiography and Indocyanin Green Angiography

What is fundus angiography?
Fluorescein and indocyanine green angiography are tests that use special cameras to photograph the structures in the back of the eye. These tests are very useful for locating the damage to the blood vessels that nourish the retina (light sensitive tissue) and in turn, checking on the health of the retina itself. In both tests, a colored dye is injected into a vein in the arm of the patient. The dye travels through the circulatory system and reaches the vessels in the retina and those of a deeper tissue layer called the choroids. Neither of the tests uses any harmful forms of radiation.

Fluorescein is a yellow dye, which glows in visible light. Indocyanine is a green dye that fluoresces with invisible infrared light; it requires a special digital camera sensitive to these light rays This indocyanine green angiography helps your doctor make the correct diagnosis and plan the best course of treatment especially in diseases like age related macular degeneration (AMD).

How is fundus angiography done?
Before the procedure, you will be asked questions about your general health and the medications that you are using. A self-explanatory consent form, which explains the side effects in detail, will be provided to you. You will have to give your consent before the procedure. You should have a light meal before undergoing the procedure and must be accompanied by a family member or friend.

Eye drops will be administered to enlarge the pupils — this takes approximately 30 minutes. You will then be asked to sit still in front of the camera while a series of color photographs of your eyes are taken. You will be given an injection in your arm, and more photographs will be taken.

The test takes approximately 15-30 minutes.

What are the side effects?
Both fluorescein angiography and indocyanine green angiography are considered very safe and serious side effects from these tests are uncommon. However, there is the possibility that a patient may have a reaction to the dyes. While fluorescein contains no iodine and is safe in patients known to be allergic, indocyanine green is currently formulated with iodine and should not be used in individuals with any known allergies. Some people may experience slight nausea after the dye injection, but the feeling usually passes quickly.

Patients who are allergic to the dye can develop itching and a skin rash. These symptoms generally respond quickly to oral medications such as anti-histamines or steroids. Very rarely, a sudden life-threatening allergic reaction called anaphylaxis can occur. This condition requires medical treatment.

There is also the possibility of an infiltrate of the dye into the skin at the injection site; this may cause some discomfort or discoloring of the skin for several days. The fluorescein dye will turn the patient's urine orange and may slightly discolor the skin as well for a brief period. Your physician can explain the individual risks of these procedures for certain patients, including pregnant women.

Sound Wave Echo Pictures of the Retina with Ultrasonography

What is ultrasonography?
This is a painless test that makes use of sound waves which bounce back or echo from the interior of the eye to create a clear picture of the anatomy of the eye. This test is needed when details of the eye cannot be seen with the instruments used in routine examinations.

How is the test performed?
You will be given eye drops to prevent pain and thick jelly will be placed on the eye. The ultrasound instrument is then gently placed on the eye. The test takes about 10 minutes and results in a picture of both the normal and abnormal anatomy of the eyeball. It is a safe and painless procedure, no X-ray exposure occurs in this test.

How is the ultrasound test used?
Your doctor can use these echo pictures to arrive at a diagnosis, the probable future health of your eye, and a treatment plan. However, the test will only reveal the structure of the eye.

What complications are likely to occur?
There are no significant complications, but there may be some temporary pain of the eyeball if it is inflamed. This can be easily treated by your doctor with no permanent side effects.

Repair of Retinal Detachment with Scleral Buckling

What is retinal detachment?
Normally the retina is firmly attached to the back of the eyeball. If it becomes detached, the eye loses vision. This is a rare disease occurring in about one person out of 10,000, each year. The immediate cause is usually a hole in the retina. It may be due to injury or surgery, but is usually due to weakness of the retina. This is sometimes called degeneration.

What is scleral buckling surgery? 
The surgery may be done under general anaesthesia (you will be sound asleep) or local anaesthesia (you will be awake but an injection will prevent any pain). The retina is reattached by freezing (cryosurgery) and with the placement of a permanent silicon patch (buckle) on the wall of your eyeball. The external stitches will melt away and do not have to be removed. Usually the eye responds to one operation; occasionally, additional surgery may be required. The eyelashes are cut before surgery but they always grow back. You will probably spend one or two nights in the hospital after the operation. Normally, only the operated eye is bandaged but, sometimes, both eyes may be bandaged for a few days. Most patients can return to work in four to five weeks.

What may I do after surgery? 
You must stay at home for at least three weeks, traveling should be avoided except to visit the doctor. After surgery you will be given written instructions regarding medication and precautions to be taken. You should carefully observe these instructions. You may be advised to lie on your side or stomach while sleeping or resting.

What are the chances of success? 
In most cases (85%) the retina can be reattached with a single operation. Occasionally additional surgery is necessary; this brings the final cure rate up to approximately 95%. The final degree of clarity of vision will not be known for three months. If you had lost your reading vision before surgery, you should find considerable improvement but probably not 100%. If your reading vision was not lost before surgery, good vision will be retained (after convalescence) in more than 90% cases. In 5% cases the retina may not re-attach, necessitating further surgery.

What are the common side effects and complications of the surgery?
Your vision will be blurred. The eye will be painful, red and swollen and there may be some mucus discharge. The pupil will be large and you may see double. These side effects are usually temporary and last only a few weeks. In many cases the eye will become more near-sighted; this can be corrected with spectacles. 

Over 90% cases have no significant complications. Occasional problems include bleeding or infection or re-detachment. Very rarely such complications could lead to the loss of all vision. Anaesthesia-related complications are also rare; the anesthetist will discuss these with you.

What about the future of my retina? 
If the retina remains attached for three months after surgery, the chance of recurrence is only 10%. If the retina of your other eye appears normal at this time, the chance of developing a detachment later on is approximately 12% in the eye that has not been operated.

Can retinal detachment be prevented? 
In some cases the retina is more fragile and prone to formation of holes or breaks. If these are detected and sealed in the early stages by laser or cryosurgery, retinal detachment can be prevented. People who are likely to develop retinal detachment should have periodic examinations done after dilation of the pupils. Some of the situations where this is desirable are:

  • History of detachment in one eye 
  • Family history of retinal detachment 
  • History of injury to the eye or its surrounding bones 
  • History of flashes and floaters 
  • Sudden onset of floaters or change in the character of floaters

Surgery of the Interior of the Eyeball with Vitrectomy

What is Vitrectomy?
This is a very delicate operation performed with an operating microscope and special needle-sized instruments. The most common indication for this operation is removal of the vitreous, which has lost its transparency and, therefore, has become an obstacle to the incoming light. In this surgery most of the non-transparent vitreous is removed and replaced with a clear solution. Vitrectomy may also be used to remove the pulling forces of the vitreous, which may have led to detachment of the retina. This operation may also be used to remove blood clots, infectious material, cataract, foreign bodies, and abnormal membranes from the interior of the eyeball. Sometimes it is done for diagnostic purposes for diseases of unknown origin. Occasionally it may be necessary to inject air, gas, or silicone oil into the eye after removing the vitreous gel.

How is the operation performed?
The surgery may be done under general anaesthesia (sound asleep) or under local anaesthesia (you are awake but feel no pain). The operation takes two to four hours. Usually one operation is sufficient, occasionally additional surgery may be required. The eyelashes are cut but they always grow back. Most patients stay in hospital for one or two days; longer hospitalization may sometimes be necessary. A face-down position for sleeping may be suggested for several days. The operated eye will be bandaged for one day. Occasionally both eyes may need to be bandaged to ensure complete ocular rest.

What may I do after the operation?
For the first two weeks you should rest at home. Travelling should be avoided except to see the doctor. If gas has been injected into the eye, you should avoid air travel for several weeks until specifically authorized by the doctor. Postoperative instructions will be given to you at the time of discharge and these should be strictly followed. Most patients are able to return to their routine in four weeks.

What are the chances of success?
The vision improves to some degree in 90% of simple vitrectomy cases. In difficult cases however, improvement is seen in approximately 60% of the cases while in others it may remain the same or even decrease. The final degree of clarity of vision is usually not evident for about three months. How much vision a patient will ultimately have is difficult to predict in individual cases. Patients are usually able to see large objects but fine vision and reading vision may not improve.

What are the side effects and possible complications of surgery?
Blurred vision, pain in the eye, redness and swelling, mucus discharge and enlaged pupil and double vision are usually the temporary side effects and they clear up in a few weeks. Usually there are no complications, but some patients may have problems such as recurrent bleeding, infection, or elevated pressure in the eye. Rarely, a retinal detachment or cataract may develop requiring further surgery, either during or after the vitrectomy operation. Very rarely a complication may lead to the loss of all vision. To find out about anesthesia related complications, one may consult and anesthetist.

Instructions for Patients who have had Surgery of the Retina or Vitreous

The following precautions should be observed for three weeks:

  • Do not lift anything that weighs more than five kilograms.
  • Do not bend over so that your head is below your waist.
  • Avoid sleeping on the operated side, unless you are instructed to do so.
  • Avoid sexual intercourse.
  • Avoid alcoholic beverages.
  • Do not rub the operated eye.
  • Avoid vigorous activity.
  • No automobile trips except to visit the doctor.
  • You may bathe carefully from below your neck and shave, but do not get the eyeball wet for at least two weeks. You may carefully clean the forehead and cheek with a wet cloth.
  • You may watch television sparingly.
  • You may gently rub the eyelids with cotton or a clean tissue moistened with warm water. Do not bathe the eyeball.

Eye bandage

  • You may remove the eye patch on your doctor's advice (usually after one day).
  • Always wear either protective glasses or an 'eye shield' to avoid accidental injury.

Medication
Follow the instructions that are given to you when you leave the hospital.

Follow-up appointment
Please adhere to the follow-up appointment date given to you at the time of discharge. In case of doubt, contact us.

Some discharge from the eye is to be expected. This should normally show gradual improvement, but increasing discharge or pain or decreasing vision should be reported to the doctor immediately. You may call us for any other concerns that you have.

Instructions for Patients who have had Surgery of the Retina or Vitreous

Special Face-Down orders
1. Certain retinal detachments require the placement of a bubble of sterile gas in the interior of the eyeball. When you observe a face-down position this gas rises toward the ceiling and pushes the retina back into place. The gas will be absorbed by the eye within a few weeks.

2. You will be asked to lie on your side while in the recovery room.

3. After moving to your ward bed, you will be placed in position (A) or (B).
(A) Place a pillow under the chest and a rolled-up towel (or small blanket) under the
forehead.
(B) Lie on your side with your face turned toward the mattress.

NOTE: The long axis of the head should always be parallel to the floor.
4. You may lie on your back for 3 - 4 minutes for changing of the eye bandage, putting eye drops or for the doctor's examination.

5. For the first 10 days after surgery, you have a choice of five positions:
(A) Prone (as illustrated) 
(B) On side (as illustrated)
(C) Sitting with elbows on knees.
(D) Sitting with forehead on table edge, with small pillow (as illustrated).
(E) Walking in the house with the long axis of head parallel to the floor.

6. Eat facing down, drink beverages with a straw.

7. IF YOU HAVE PROBLEMS, CONCERNS OR QUESTIONS

You can ask the doctor about your concerns at the time of your examination at the L V Prasad Eye Institute. If you feel you cannot wait until the next appointment, you may call us at (040) 2354 8267/2360 8262. If you have an emergency during the night, a weekend or on a holiday, come for emergency care at the front door of the Institute.

You can also send us a fax at (040) 2354 8271 or an email at retina@lvpei.org. While sending a fax or email always mention the patient's ID number, name and the doctor's name. Generally, we will respond in 24 hours.

The Kanuri Santhamma Retina-Vitreous Service
L V Prasad Eye Institute
Hyderabad, INDIA