Know Your Diseases
What Is Diabetic Retinopathy?
Diabetes, the “Silent Killer” affects four vital organs of body i.e. eyes, heart, kidney & nervous system. In eyes it primarily affects retina and causes Diabetic Retinopathy. Retina is like a film within a camera which receives the image of an object seen and transmits its impulse to the brain. Macula is the area on retina that is responsible for 90% of vision. Any damage to macula results in loss of vision. Diabetic Retinopathy is defined as “the damage of the retinal blood vessels, accompanied by certain structural changes in the retina resulting in vision loss”. Diabetic retinopathy remains a major cause of irreversible blindness among working age adults (20-74 years) in most industrialized & developing countries. Hence, proper & timely checkup is mandatory to prevent vision loss.
What Other Factors Promote diabetic retinopathy?
Following factors enhance the development of diabetic retinopathy.
- Duration of diabetes
- Increased blood sugar: Large & rapid fluctuation in blood sugar level increases the risk of development of diabetic retinopathy than constant blood sugar level.
- Hypertension: High blood pressure is an important factor in the development of retinopathy.
- Glycosylated hemoglobin (HbA1c) is an important parameter to monitor the long term blood glucose level control.
- High blood cholesterol
- Involvement of kidney by Diabetes
- Pregnancy in diabetic patients
- Genetic factors
How does Diabetic retinopathy affect my vision?
There are two main causes of vision loss in diabetic retinopathy.
Diabetic Macular Edema: Weakened blood vessels at macula leak, and accumulation of fluid in retina causes swelling and exudation, resulting in moderate vision loss.
Proliferative Diabetic retinopathy: Growth of new abnormal blood vessels can lead to hemorrhage in vitreous with sudden severe vision loss. Repeated bleeding results in abnormal growth of scar tissue with pull on retina leading to tractional retinal detachment.
Will all diabetics develop diabetic retinopathy?
Any person with diabetes can potentially develop diabetic retinopathy, irrespective of type of diabetes; however it is observed that nearly half of all people with diabetes will develop some degree of diabetic retinopathy during their lifetime.
How Can It Be Detected?
Detection of diabetic retinopathy is done by following methods.
- Periodic Examination of Fundus (Retina) by a qualified ophthalmologist,
- Fluorescein Angiography– It is done to see the leakage from blood vessels and growth of new blood vessels and used as a guide to do laser treatment. Fluorescein angiography cannot be done if kidney function is severely compromised.
- OCT– It is used to measure the thickness of macula and acts as a guide to treatment by anti VEGF agents i.e. Avastin & Lucentis.
Is It Preventable?
Yes. Initially, diabetic retinopathy is symptomless i.e. patients will have no complaints and they will have perfect vision and once diabetic retinopathy develops vision loss cannot be restored fully so to prevent the visual loss from diabetic retinopathy, appropriate and timely management as directed by your ophthalmologist must be instituted. Vision loss from diabetic retinopathy is preventable, only if it is diagnosed at early stage. So, at the time of diagnosis of diabetes, fundus examination must be done by a qualified ophthalmologist. Thereafter it should be done periodically as recommended by the ophthalmologist. Besides periodic checkup, prevention of diabetic retinopathy includes life style modification, exercise, cessation of smoking, control of body mass index, and treatment of coexisting precipitating disease along with treatment of other complications of diabetes.
Diabetic Retinopathy Diagnosed. Now What?
It’s true that vision loss from diabetic retinopathy cannot be restored fully. But the management of diabetic retinopathy is done with an objective to preserve the existing vision. Your ophthalmologists will examine and decide your diabetic retinopathy status and initiate the treatment accordingly to preserve your existing vision. So it is extremely necessary to adhere strictly to your ophthalmologist’s advice. To achieve the goal following strategy has to be adopted:
Management of Diabetes and its complications other than retinopathy:
Treatment of diabetic retinopathy begins with treatment of diabetes and its complications. Strict blood sugar control is the only way to prevent the development and further progression of diabetic retinopathy. Besides this, treatment of aggravating factors is also necessary to slow the progression of diabetic retinopathy. Without treating diabetes and other promoting factors, all efforts to treat diabetic retinopathy are futile.
Diabetic retinopathy management:
Lasers are the mainstay of treatment in diabetic retinopathy. The purpose of the treatment is to arrest progress of the changes within the retina to stabilize the vision, to prevent further vision loss and complications related to retinopathy- not to restore the vision.
Anti VEGF Agents (Lucentis & Avastin) & Steroids:
Anti VEGF agents are used in treatment of macular edema & prevention of new vessels growth. It comes in injectable form to administer in the vitreous cavity of eye. It restores vision to some extent for some period. So, multiple injections may be needed for sustained effect. Lucentis is FDA approved for treatment of macular edema but Avastin is a cheaper alternative to Lucentis with similar effects, in a country like India. Intravitreal steroids are also used for treatment of macular edema.
Periodic follow up with ophthalmologist
In case of advanced diabetic retinopathy with complications like vitreous hemorrhage and retinal detachment, vitreo-retinal surgery is needed to give some ambulatory vision to the patients.
What can you do to protect your vision?
Early detection of diabetic retinopathy is the best protection against loss of vision. Successful treatment of diabetic retinopathy depends not only on early detection and treatment by an ophthalmologist, but also on patient’s control of the blood sugar, blood pressure, blood creatinine, and blood cholesterol levels. Adherence to medical treatment is immensely beneficial in management of diabetic retinopathy.
Diabetic retinopathy fundus