DIABETIC RETINOPATHY

Fig. 1: DIABETIC RETINOPATHY

DIABETIC RETINOPATHY - Patient Education

DIABETES

Our body is made up of several trillion cells. Every cell receives its energy from ‘glucose’.  Glucose reaches all the cells through blood. In optimal amounts, this glucose is “life giving” to all the cells. But if this glucose increases in blood, it acts like poison and damages all parts of the body. This condition, where in the blood glucose levels rise to abnormal levels, is called diabetes.

“Insulin’ is a hormone which regulates the blood sugar level.  Due to either decrease in this insulin or it’s improper functioning, the sugar levels rise. These are Type I and Type II diabetes.

Diabetes damages almost all the organs in the body. The most affected parts are retina (Diabetic retinopathy), Foot (Diabetic foot) and kidneys (Diabetic nephropathy).

DIABETIC RETINOPATHY

Our eyes are “Living Cameras”. They continuously take images and send them to brain for printing. In fact camera was invented based on our eyes.

The following figure compares a camera and our eye:

                 

Fig. 2: Eye and Camera

Just like a film in camera, our eye too has a thin film in the back of its inside. This film is called as ‘retina’. This is thin wafer like, and is spread like a plastic sheet over the inner surface of eye ball. Retina is the most important part of eye. Imagine a camera without film.

Fig. 3: Anatomy of Retina

As all parts of our body, retina too needs blood supply for its survival. The blood vessels 

which supply blood to retina are called as ‘Retinal blood vessels’. These blood vessels are arranged in branching and sub-branching fashion, just like the roots of a big tree. These are like pipes which carry blood.

High sugars in diabetes weaken these blood vessels and puncture them at certain sites. This leads to leakage of blood and damage to retina. This weakening, leaking and damage caused by diabetes to the retina is called as “Diabetic Retinopathy”.

 This leak starts in a small manner and grows gradually to bursting of vessel with severe bleeding and loss of eye sight. This is similar to rusting of iron water pipes. Rusted water pipe does not explode immediately. It initially starts leaking drop by drop. If not corrected, it will start leaking in stream like fashion. If not corrected even in this stage, the pipe will break up leading to a gush of water explosion. Similarly, in diabetic retinopathy, in initial stages there will be droplet like leaks. These will increase over time, to a stage where the blood vessels burst leading to a gush of bleeding and loss of sight.

Any material present in the blood can leak out of blood vessels. It can be water leak, which is called as ‘Edema”, or the ‘fatty material’ leak which are called ‘exudates’. Or the whole blood can leak which are called as ‘haemorrhages’.

This disease progresses in stages and leads to severe bleeding in last stages. Patient loses sight in this last stage. Till then patient does not have any symptoms in his eyes. His sight and eyes will be perfectly normal. Patient has no clue regarding the damage which is happening in his eyes. If patient waits till he gets symptoms, it would be too late and he may remain blind lifelong. Few patients may notice decreased vision in early stages due to Macular Edema, but not all. Macula is the central part of retina, which is mainly responsible for our vision.

The only way to prevent such blindness is to treat it with Eye injections or Laser or both at the right time. The right time is decided by a retina specialist after some tests. This treatment will stop the progression of disease; it does not cure the disease. It means, blindness can be prevented but not cured in most of the situations.

Diabetic retinopathy is like a bomb in the eye. It does not produce any effects till it explodes. You can only prevent it from exploding. Once it explodes very little can be done.

All diabetics should undergo regular retina screening. When necessary, laser treatment  or intravitreal injections should be taken. Strictly following this protocol is the only method to prevent blindness in diabetics.

                  Fig. 4: Stages of Diabetic Retinopathy

                  DIABETIC RETINOPATHY- Frequently Asked Questions

1.            How serious is diabetic retinopathy?

Ans.  In last stages, this is as serious to sight, as a heart attack is for life.

2.            What is “good sugar control”?

Ans.  Fasting blood sugar of 110 mg% or less and Post lunch sugar of 150-160 mg% can be considered good.

3.            Who has more chances of developing diabetic retinopathy?

Ans.  a. long time diabetics.

         b. uncontrolled sugar levels.

         c. high fluctuations in sugar levels.

         d. people who along with diabetes have Blood pressure, kidney problems, anaemia, heart problems etc.

4.  How do I detect diabetic retinopathy?

Ans. Patient cannot detect it in early stages, as he has no symptoms. By the time he gets symptoms, the disease would have been in late stages. It can be detected only by dilated retinal examination (examination of retina after enlarging the pupil) by a retina specialist.

Many diabetics are not aware of this fact. They don’t consult a retina specialist till they get visual problems. By that time, the disease would have been in serious stage, with no treatment. That’s the reason; we have many diabetics who are blind. Spread of awareness regarding this disease can prevent many others from becoming blind.

5.            What are the symptoms in diabetic retinopathy?

Ans. In early stages it has no symptoms. This disease has no early warning signs. In later stages patient may see some black spots in front of eyes (floaters), or he may suddenly lose his sight. These are seen after a severe bleeding in the eye. In macular edema (Water logging of the sensitive part of retina) patient has decreased vision.

6.            What is pupillary dilatation?

Ans. Retina is situated like a spreadsheet in the back of eyeball. It can be compared to a cinema screen in the hall. The only route to see it is the pupil. Normally our pupil is small and does not allow total view of retina. If we enlarge it, we get a fuller view of retina. E.g. imagine yourself watching the movie screen from outside the hall, through the door gap. If the door is only slightly open, you get a smaller view of screen. If u wide open the door, u get the full view. Similarly, if pupil is widely opened, we get a fuller view of retina. Another example is "Looking through the Key hole and Looking through Open door". The pupil is enlarged using eye drops. This procedure is called pupillary dilatation.

It takes half hour to hour. After the pupillary dilatation, patient has photophobia (inability to see light) and decreased vision for a couple of hours. These are very mild and transient.

Fig. 5: Pupil Dilatation

7.            What is diabetic retinopathy screening?

Ans.   It’s the retinal examination done to detect the disease in early stages, before patient develops symptoms.

8.            What is prevention?

Ans. If in screening, it is detected that patient has diabetic retinopathy in severe stage, it has to be treated with lasers or Intravitreal Injections to prevent further progression and blindness. This is called prevention.

This can be compared with a bomb in bus stand. A bomb as such does not produce any effects until it explodes. Till then, it looks normal. You see a suspicious bag in bus stand. You call the police, and police call a bomb squad. The bomb squad do some tests to confirm, whether it is really a bomb. If it turns out to be a bomb they defuse it with some defusing techniques. Thus they prevent an explosion, which otherwise would have lead to severe property and life damage. But after the defusion do u expect any change in the bus stand? No. it would be just like before. All the activities of police and bomb squad were only to prevent an explosion but not to improve existing bus stand.

If diabetic retinopathy is a bomb, all diabetics are suspicious. Retina specialist is the bomb squad who diagnoses the bomb. The test used by him for this purpose is Retina screening. If the disease is detected, it is defused by laser treatment, which prevents an explosion and blindness.

If patient doesn’t follow the above protocol, he will end up in complicated stage. Bomb has exploded. In such situation, you can only do a damage control. Regaining normal vision is almost impossible.

9.            What is retinal ischemia?

Ans.  As said earlier there will be leakage of blood in the retina. Due to this and due to blockage of blood vessels , some areas of retina become devoid of blood supply. These areas without blood become “lifeless” and are called “ischemic areas”. These areas release a poison called "VEGF" (Vascular Endothelial Growth Factor), which damages normal retina.

These ischemic areas are like ‘weeds’ in a field. These by themselves are useless. Upon that they spoil the whole crop in the field, if left untreated. Similarly if the retinal ischemic areas are left unburnt, they will spoil the whole retina and cause blindness. The burning of these ischemic areas is done by laser treatment. The VEGF poison is neutralized by Intravitreal AntiVEGF injections

10.         What is Fundus Fluorescein Angiography (FFA)?

Ans. In retinal screening, we will know the effects of leakage, like bleeding etc. But the areas of leakage won’t be known. Moreover ischemic areas are not well made out. These will be known by FFA. This will also give insight about macular edema and damage. The number of laser treatment sessions, will be decided after FFA.

A dye is injected in the arm veins. Retina is examined or photographed to know the flow of dye. This is an OPD procedure. Needs at least 2 hours of empty stomach.

This dye will cause the urine to become orange for couple of days. Some may experience nausea or even vomit. Very very rarely an allergic reaction can happen. Overall it is a safe procedure. With the advent of OCT, the role of FFA is coming down. Since it is involved with injection and associated risks, FFA is now rarely used.



11. What is OCT?

Ans. OCT is short form for Optical Coherence Tomography. It is similar to the CT scan of the body. This machine gives us the cross section images of retina, which helps us in knowing the amount of macular thickness, Macular Cysts, Breaks and Traction.
This is an invaluable tool in the management of Diabetic Retinopathy.  

12.         With whom should I undergo retina screening?

Ans. A retina specialist is the best person for this. If he is not available, any ophthalmologist who has experience in retinal examination, and has equipment, can serve.

13.         When should I undergo retinal screening? How frequently should I undergo it?

Ans. Type 2 diabetics should get their first retinal examination at the time of diagnosis of diabetes. Depending upon the retinal situation, retina specialist will decide about next visit. Usually yearly checkups are advised.

14.         With whom should I undergo laser treatment?

Ans. Laser treatment is a complex procedure which requires training and experience. You should get it done with a retina specialist or any ophthalmologist who is trained in such procedures.

15.         What is laser treatment? Is it an operation?

Ans. No. laser is a type of light beam which is used to burn the ischemic areas in the retina. Laser beam is made to fall on the specific areas of retina with the help of special equipment. This will also handle the leakage spots. Laser kills the retina by burning it. With the advent of Intravitreal anti VEGF injections, the role of laser is reducing.

This is again an OPD procedure, and does not require any admission, or injections. It takes 15 minutes to 45 minutes. Usually 2-3 sessions are needed.  This requires pupil dilatation.

16.         Does laser treatment improve my eyesight?

Ans. No. it is only preventive. It only prevents the disease to grow further, which can lead to blindness. It does not get back the lost sight.

17.         I am a diabetic since many years. I don’t have any problem in my eyes. Do I still need to undergo retinal examination?

Ans. Absolutely yes. If you wait for the problems to occur, then it would be too late to save your sight. You have to undergo regular retinal screening as per protocol.

18.         I am a diabetic since many years. I never underwent retinal screening or retinal laser treatment. I suddenly lost my vision yesterday. What should I do?

Ans.  You might have developed severe vitreous bleeding, which requires Intravitreal Injection/s. You might be having a retinal detachment too. In such situations, a complex vitreoretinal surgery may be needed. The chances of regaining normal vision are very less especially if it’s a RD.

19.         I underwent laser treatment thrice and also received Intravitreal Injections. Is there a necessity for me to still undergo retinal examination and do I require further laser treatment in the future?

Ans. Yes. Even after laser treatment depending on your diabetic status, your diabetic retinopathy may still progress. So, frequent retinal examinations are still necessary. Some people may need further multiple injections. As long as you have diabetes, Diabetic retinopathy stays with you. Just like you undergo regular sugar checkups, you need to undergo retinal examination too.

20.         Regular retinal screening and timely laser treatment and / or Intravitreal Injections. Are these sufficient? Will they protect the retina for lifelong?

Ans. Not totally. The laser treatment works properly only when the blood sugars are under total control. People with uncontrolled sugars, may still develop significant retinal damage in spite of retinal laser treatment. Apart from sugars, other bodily parameters too should be under control like BP, anemia (lack of blood), kidney problems, cholesterol problems etc. Bodily derangements show their effect on retina.

21.         What are intravitreal Injections?

The usually used intravitreal injections in Diabetic Retinopathy are anti-VEGF injections.

As we learnt earlier, in Diabetic Retinopathy, the retinal blood vessels get damaged and leak into the retina. This leakage prevents certain retinal areas to get their blood supply. Such areas which are devoid of blood supply gets damaged, and are called ischemic zones. Such Ischemic Areas are like weeds in the field. The weeds by themselves are useless, and if left alone, will spoil the whole field. Similarly, these ischemic areas, are useless, and if left untreated, will spoil the whole retina, leading to blindness. This damage, they create, by producing and releasing a poison, called VEGF (Vascular Endothelial Growth Factor). This poison causes bleeding and Edema in the retina.  Anti-VEGF is the antidote for this VEGF. These anti-VEGF injections neutralize the poison, and thus save the retina. These are given in situations like Retinal Bleeding, Macular Edema etc.

Another way of dealing with these ischemic zones, is to burn them, just like burning the weeds in a field. This burning is done with LASER, which forms the basis for LASER treatment, which was described earlier. Since LASER burns the retina, it will cause loss of peripheral vision and reduction in night vision. Also laser may increase existing macular edema and worsen the vision. Whereas, injections do not kill the retina and they reduce the edema. They may improve the vision which is not the case with Laser. Since anti VEGF injections have more benefits, they are more often used in Diabetic Retinopathy. The use of laser is drastically coming down.

22.         Whenever I go to my retina specialist, they instill eye drops in my eyes, and make me wait for almost an hour. Why is that? Is it that necessary?

Ans. Yes. A large pupil is very necessary for retinal examination. The eye drops are to enlarge the pupil. Retinal examination without pupillary dilatation, is like looking through a key hole. It will only give a partial view of retina, and the peripheral disease can be missed. Dilatation is like opening the door, which gives full view.

23.         What is vitreoretinal surgery? When is it needed?

Ans. Vitreoretinal surgery is the last option to save at least some of retina. It is a complex surgical procedure, which requires special equipment and skills. It is usually required in complicated stages. It would be the last step. Usually advised when all other doors are closed. The results are usually poor in many situations. It is better, not to get such a stage.    

In Vitrectomy the surgical instruments enter the eyeball. The vitreous is removed, the subretinal fluid is removed and vitreous is replaced with air , fluid or silicon oil.

                          

Fig. 6: Schematic depiction of Vitreoretinal surgery

24.  What are the risks of retinal surgery?

        No surgery is riskless. Vitrectomy has risks like Bleeding, Infection, Raised Intraocular pressure, Cataract etc..

             Most surgeries are successful, although a second operation is sometimes needed.

25.  What are the visual expectations after surgery?

        Vision may take many months to improve and in some cases may never return fully. The amount of visual recovery cannot be predicted before surgery. Its only a matter of luck and chance. Unfortunately some patients do not recover any vision.

26.  What happens to the eye if Vitrectomy is not done?

            The eye will slowly lose all  existing  vision and becomes totally blind. It squints. The eye may eventually become small and shrunken causing an ugly cosmetic appearance.

27. Is defective vision always irreversible? Is my future always bad?
       
      No. Many cases with Macular edema, or vitreous hemorrhage respond well with treatment and get back some good vision, if treated early.

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Dr. Murali Mohan Gurram is one of the very few ocular surgeons who can operate both Phaco and Vitreoretinal surgeries under Topical Anesthesia. With more than 20 years’ experience, his advice is something which you can surely rely on.

Dr. Murali Mohan Gurram is available at “SURALI CLINICS” Women and Eye Care. H. No. 12-1-86/A/149, Anand Nagar X Roads, Bandlaguda 500068,

GPS Position: 17.369639 78.573479

Call 6303476390 for appointment. Whatsapp 9848322436 for online consultation.

Email: suraliclinics@gmail.com

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Diabetic Retinopathy blindness has no cure. Prevention is the only way.

Regular retinal screening and Timely Laser treatment and / or Intravitreal Injections is the only way to prevent Diabetic blindness.