Vision And Its Complications Due To Diabetes

Diabetes is a metabolic disorder which interferes with body's ability to use and store sugar. It usually affects adults in their late forties or fifties. However, these days owing to lifestyle changes even young people can get diabetes. 

The classic symptoms of diabetes are
increased thirst, frequent urination, weight loss, tiredness or blurred vision. Uncontrolled diabetes can
affect eyes, nerves and kidneys. Individuals with diabetes are more likely to develop cataracts at a younger age and are twice as likely to develop glaucoma as are non-diabetics. However, the primary vision problem caused by diabetes is Diabetic Retinopathy which damages the blood vessels of the retina.

In uncontrolled diabetes, high sugar in the blood can damage blood vessels of the eye. As damage progresses, they begin to leak which results in accumulation of the fluid in the central part of the retina. This deterioration of the blood vessels causes hindrance in supply of oxygen and nutrients needed by retina to stay healthy.

Warning Symptoms
•Blurred, double, or distorted vision or difficulty in reading.
•Floaters or spots in your vision.
•Partial or total loss of vision or a shadow or veil across your field of vision.
•Pain, pressure, or constant redness of the eye.

All diabetics are at risk of getting Diabetic Retinopathy. The risk multiplies the longer a person lives with diabetes. It has been observed that about 80% of long standing diabetics (15 years or more of diabetes) have some damage in the blood vessels of retina. Diabetic retinopathy can occur at a young age in juvenile diabetics.

Diabetic retinopathy is a silent vision thief. In early stage, there is hardly any symptom. Hence, a diabetic must strictly get his eye exam done every year. If detected early, vision loss can be prevented. But, once the damage is done, the effects are irreversible.

There are two main stages of Diabetic Retinopathy:
The early stage is called Non Proliferative Diabetic Retinopathy. In this stage there is damage to the retinal blood vessels, which causes swelling of macula (central part of the retina). Known as Diabetic Maculopathy, symptoms manifest as blurred vision.

The advanced stage is called Proliferative Diabetic Retinopathy. This is the most serious stage of Diabetic Retinopathy. In this stage, there is an overgrowth of new fragile blood vessels into the areas deprived of oxygen. These new blood vessels can lead to various complications which could further lead to a detached retina or glaucoma.  If it is not treated even by this stage, the patients are at risk of going blind due to occurrence of vitreous hemorrhage and retinal detachment.

The ophthalmologist will do a comprehensive eye investigation to detect Diabetic Retinopathy. The eye exam includes visual acuity tests, eye pressure measurements and direct visualization of the retina with an ophthalmoscope. Sometimes the ophthalmologist may require more extensive imaging with technology like Fundus Fluorescein Angiography (FFA) and Optical Coherence Tomography (OCT) to capture the details of the damage caused by abnormal blood vessels & assess the severity of the condition.

A. Laser Photocoagulation: It is the most common line of action for diabetic retinopathy treatment. But remember, this can only save the existing sight level and cannot make it better. In laser treatment, the retina specialist uses laser to destroy areas of retina deprived of oxygen which helps to prevent growth of new blood vessels into these areas. It can be done in multiple sessions. In most cases, this procedure causes the new blood vessels to regress and the swelling to subside. It usually takes three to four months to be fully effective.

B. Vitrectomy: Sometimes the new blood vessels bleed into the gel like centre (vitreous) of the eye. This condition – Vitreous hemorrhage can lead to a sudden loss of vision. If the vitreous hemorrhage is persistent then a procedure called Vitrectomy is recommended. This is a microsurgical procedure for diabetic retinopathy treatment which removes the blood and scar tissue from the centre of the eye. Many patients have improved vision after vitrectomy.

C. Intravitreal Injections: Thesehelp patients with gross swelling in the macula. It may require injections of vascular endothelial growth factor (VEGF) inhibitor drug or steroid into the eye to reduce the growth of abnormal blood vessels and leakage of fluid from them. These may also be used prior to surgery to reduce the bleeding.

The choice of treatment depends on the stage of the disease, the age of the patient and the recommendations of the retina specialist.

Success Rate
Patients who have already lost vision from the disease usually do not regain the original vision. However, vision loss from complications such as bleeding into the eye or cataracts can be regained after diabetic retinopathy treatment. There is evidence that proper blood sugar control can delay and limit the progression and complications of Diabetic Retinopathy for people with diabetes.

Cataract is the clouding of the lens of the eye that leads to blurred vision. Although anyone can get cataracts, theytend to develop at an earlier age in people with diabetes and progress more rapidly than in non-diabetic people. The treatment of cataracts is through surgical removal of the cloudy lens, which is removed and replaced by a clear artificial lens in surgery thus helping you to see better.

Glaucoma is caused by the build-up of fluid pressure inside the eye. With age, disease, trauma and other factors, the channels which drain the fluid from the eye get blocked. This results in increased pressure inside the eye which damages the optic nerve. The optic nerve transfers visual messages to the brain. When it gets damaged, it impairs the visual ability of an individual leading to irreversible blindness. A person with diabetes is nearly twice as likely to get glaucoma as compared to other individuals.

Treatment of glaucoma requires lowering the eye's pressure by increasing the drainage of aqueous humor or decreasing the production of the fluid by using eye drops in the affected eye. Surgical management of glaucoma includes a procedure where an opening is made to create a new drainage pathway for the fluid to leave the eye easily. Alternatively, glaucoma management by lasers includes Trabeculoplasty in which a laser is used to increase the drainage and reduce the pressure inside the eye. Diabetics can prevent glaucoma by getting a yearly glaucoma screening from their eye doctor.

People with diabetes are also more at risk of a less common form of glaucoma i.e. Neovascular glaucoma. In this form of glaucoma there is growth of newblood vessels on the iris which block the normal flow of the fluid out of the eye, raising the ocular pressure and leading to glaucoma. Laser surgery is used to reduce the vessels.

•You must get a complete eye checkup done regularly by an ophthalmologist
•Keep strict control over your glucose and lipid profile levels.
•Maintain a healthy level of fitness with a normal blood pressure
•Quit smoking
•When considering pregnancy, women with a history of diabetes should have an eye exam prior to and during pregnancy

-Dr. Siddarth Sain,

Sharp Sight Centre, 
New Delhi

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