DIABETES & THE EYE
Diabetes is now an epidemic in India. With Diabetes comes a host of other conditions. The more significant one is Diabetic Retinopathy. Longstanding Diabetes Mellitus damages the small blood vessels of the retina, which normally supply oxygen to the retina and thus keep it alive. These damaged vessels either leak or close down. If the leakages occur in the central part of the retina called macula, it leads to loss of central vision. Closure leads to oxygen starvation of the retina, which finally leads to formation of abnormal new vessels to try and improve oxygen supply, these fragile vessels can bleed causing blindness. Diabetic Retinopathy is a progressive and irreversible eye disorder that ultimately leads to blindness.
Diabetic Retinopathy is positively correlated with the duration of diabetes. There are other things which along with diabetes make retinopathy worse; i.e. High Blood Pressure, Pregnancy and Smoking.
PREVALENCE OF DIABETIC RETINOPATHY IN INDIA
Diabetes Epidemic affects 61 million Indians (highest in the world) and is likely to affect 70 million by 2025 (WHO)
That means every sixth diabetic in the world is an Indian.
Both Diabetes and Diabetic Retinopathy needs to be detected and treated as early as possible because both can be controlled through proper management.
Affects up to 80% of all patients who have had diabetes for 10 years or more.
Although India accounts for approximately 15% of the global burden of diabetes, it contributes 1% of the world’s diabetes research. There is hardly any data available on the quality of diabetes care, no national monitoring system for processes and outcomes of care, and no translational research to turn knowledge into action.
Health care facilities are concentrated in large urban centres, are focused on tertiary care, and cater to the urban affluent. Government-run facilities are often crowded and under-resourced, so even low- and middle-income patients prefer private care or alternative medicine.
Sai Retina Foundation, has launched a special project on Diabetic Retinopathy Mitigation Project in East and North East Delhi which goes into the interiors with the Mobile Retina Van to screen people free of cost for diabetes and treat them for any related eye diseases, to increase awareness in the general public about the disease and all associated health implications and guide them towards regular health check-ups and necessary precautions.
INVESTIGATIONS FOR DIABETIC RETINOPATHY:
If diabetic retinopathy is noted, colour photographs of the retina may be taken and FLUORESCEIN ANGIOGRAPHY performed. This involves dilating the pupils and injection of a fluorescent dye into a vein in the arm. Photographs of the retina are taken rapidly as the dye passes through the retinal blood vessels. This test helps in determining if laser photocoagulation treatment is necessary. If treatment is to be done, it helps in identifying what structures and areas need treatment with laser.
OPTICAL COHERENCE TOMOGRAPHY (OCT), which is newer non-invasive diagnostic modality provides a cross-sectional view of the retina and helps in quantifying the amount and type of swelling and guides the treatment.
TREATMENT OF DIABETIC RETINOPATHY:
PHOTOCOAGULATION involves the use of a LASER beam to seal leaking blood vessels and prevent growth of abnormal blood vessels. This procedure does not require hospitalization. In background retinopathy, if blood vessels are leaking fluid into the macula, laser treatment stops the leakage and may improve or stabilize vision. In proliferative retinopathy, laser treatment may involve one or more sessions depending on the type or severity of retinopathy. Laser treatment significantly reduces the chances of severe visual loss by destroying the abnormal blood vessels and preventing growth of more such vessels. Vision may improve or stabilize within several weeks to a year. It is important to remember that laser treatment is not a one-time procedure. Regular follow-up is extremely important. Your doctor will tell you when to return for a check-up.
INTRAVITREAL INJECTIONS – Recently, along with laser treatment, certain medication when injected into the eye or just outside the eye has shown encouraging results. These include anti-VEGF agents such as Avastin, Lucentis and Macugen. They act by reducing macular edema i.e. the swelling in the retina as well as inhibiting growth of abnormal new vessels, or by reducing bleeding from new vessels which may be refractory to conventional laser treatment.
Another agent used is the steroid Triamcinolone Acetonide. This can be either injected into the eye (intravitreally) or into the side of the eye (Sub-Tenons). This agent works well for diabetic macular edema (swelling). However, increase in eye pressure and increased incidence of cataract, are potential side effects. These medicines should therefore be used cautiously and judiciously.
VITRECTOMY (VITREOUS SURGERY) – If the vitreous is too clouded with blood or there is traction retinal detachment, laser treatment will not work. In this situation, a surgical procedure called VITRECTOMY needs to be performed. In this operation, opaque vitreous gel is removed from within the eye by a special instrument that simultaneously sucks and cuts the vitreous. Membranes on the retina which are responsible for traction and recurrent bleeding are dissected. More complete photocoagulation can then be carried out. In case of retinal detachment due to traction in severe cases, gas or silicone oil tamponade is paced at the end of the procedure.
REMEMBER
• Diabetes is a common cause of blindness
• In case a patient is a diabetic for more than 5 years, there is a fair chance that you might have developed diabetic retinopathy
• He/she might have developed Diabetic Retinopathy, in spite of having good vision
• For the early detection and to begin the treatment, you must refer the patient to the retina specialist at regular intervals
• Diabetic retinopathy is largely a treatable condition. Early detection and treatment saves eyes.
• The patient should keep his/her blood sugar level, hypertension, increased blood lipids & cholesterol and (kidney) disease well under control.
• Quit smoking
• Regular exercise and balanced diet.
• Timely referral by the first contact physician prevents a diabetic from going blind.
Dr. J. S. Guha is Senior Vitreoretinal Surgeon, Sai Retina Foundation