"The effect of diabetes on the retina is called diabetic retinopathy."
I am a diabetic. Why do I need a retina check up?
Diabetes mellitus is a disease in which our body fails to utilize blood glucose resulting in increased blood glucose levels. The increased blood glucose has harmful effects on almost all organs of the body, including the retina, hence a retina check up is important
How does diabetes affect the body?
Technically diabetes is a "microangiopathy" which simply means small blood vessel disease. In this cells that line the blood vessels from the inside get damaged due to high sugar. This results in disturbance of blood flow through these vessels and leads to clot formation. The clot formation, in turn, leads to the poor blood supply and therefore poor oxygen flow to the organs. The effect of diabetes on the retina is called "diabetic retinopathy"
What happens in Diabetic retinopathy?
As described earlier, high blood sugar damages the blood vessels of the retina. This results in bleeding and swelling of the retina. Multiple patches of blood and cholesterol appear. In advanced stages, there is a formation of "new blood vessels- neovascularisation"
What causes vision loss in diabetes?
In early stages of diabetic retinopathy, there is no problem in vision. Vision loss occurs in late stages due to the following:
- Swelling of the central retina which is termed macular oedema
- Bleeding into the eye caused by rupture of the new vessels - vitreous haemorrhage
- Retinal detachment.
- Lack of blood supply - ischemia
What are the investigations the may be required?
In a majority of cases, simple examination by your doctor is sufficient to diagnose diabetic retinopathy. However, investigations may be required in advanced cases. 2 common investigations are OCT (optical coherence tomography) and FFA. OCT is a non - invasive test to scan the retinal layers. It is used mainly in cases of macular Oedema. FFA is a test to study the retinal blood supply or the lack of it and is helpful in predicting the chances of bleeding.
How is diabetic retinopathy treated?
If patients come early, no treatment is required. The disease can be managed simply by control of diabetes and associated risk factors like blood pressure, cholesterol etc. Patients that need treatment are usually managed by lasers. There as an increasing role of injections in the modern era. Surgical treatment is also not uncommon.
What is the role of laser in treating diabetic retinopathy?
Currently, the main role of the laser is to stop/prevent bleeding in patients with new blood vessels. It is best done before there is bleeding. There are certainly important considerations that one must remember:
- The laser is absolutely safe. It is an OPD procedure. There are no injections/ cuts etc and patients can resume work the next day.
- Lasers can stabilise but not reverse the disease. Therefore visual improvement is rare.
- Lasers cannot clear pre-existing blood. Surgery is required for the same.
What is the role of injections? It sounds so scary to take injections into the eye!!
Though it sounds scary, Injections into the eye ( intravitreal injections) are absolutely safe and almost painless as the eye is numbed by putting eye drops. There is no need to worry at all.The key role of injections is in the management of diabetic macular oedema. It is the only way to improve vision (though not guaranteed) in a diabetic patient with macular oedema.
Are injections a onetime treatment? Will I need multiple injections?
As with any medicine, the effect of injections also reduces with time. Therefore multiple treatments are usually required. There are two main categories of injections
- Steroids: which have an effect for about 12 weeks
- AntiVEGFs: effect lasts for only 4 weeks
Both the injections have their pros and cons. The doctor usually takes into consideration all the factors and decides whats best for you. It is important to maintain good control of sugar during the treatment as these procedures cannot be done if sugars are high. Also, the injections will not be effective if one doesn't control sugars
When is surgery required?
The main indications for surgery are bleeding inside the eye (vitreous haemorrhage) that fails to clear on its own and retinal detachment. At "Mumbai Eye Retina Clinic" we use the sophisticated micro incision vitreous surgery - MIVS technology for surgery. All surgeries are done on a day care basis and the patient is usually backed home in 3-4 hours.