Diabetes and the Eye
How does diabetes damage the ?
There are three major eye diseases frequently seen in patients with diabetes:
Diabetic retinopathy: Diabetes causes the blood vessels in the retina at the rear of the eye to be destroyed.
Cataract: This is a clouding of the transparent lens inside the eye . Patients with diabetes can suffer from cataract at an earlier age than normal.
Glaucoma: Damage to the fibers of the optic nerve cause increasing loss of vision . The risk of a diabetic developing glaucoma is four times higher when compared to normal people.
What is diabetic retinopathy?
Diabetic retinopathy is an important cause of blindness in adults. Early diagnosis and timely treatment are very important. Initially, the capillaries in the retina begin to bleed and serum leaks out of the blood vessels. The leaking liquid causes the the visual centre (yellow dot – the macula) to swell and vision becomes blurred. This condition is known as macular edema. Macular edema can be seen at any stage of diabetes.
Due to blockages in capillaries the retinal tissue does not receive sufficient oxygen. When the retinal tissue lacks oxygen it creates new blood vessels, but these new blood vessels are not as robust as its own blood vessels and they bleed easily. This intraocular bleeding leads to loss of vision.
However long a person has suffered from diabetes, the greater the risk of developing diabetic retinopathy. Diabetic retinopathy can be seen in approximately half of all patients with diabetes.
A patient with diabetes should definitely not wait for symptoms to emerge. It is recommended that everyone who has diabetes should have a comprehensive fundus examination of the eye every 6 months or at least once a year. As a complement to the examination, fundus fluorescein angiography (FFA) and OCT (macula) tests may be required. Retinal hemorrhages smaller than 50 microns, that are not yet visible, can be seen with an angiography. During a FFA examination the vessels of the retina are seen as a result of a special dye injected into the arm. In this way, leaking or bleeding vessels are easily identified.
How is diabetic retinopathy treated ?
Argon laser photocoagulation, applied to the retina, has an important role in the treatment of diabetic retinopathy. This treatment is carried out once a week for a number of sessions. It’s purpose is to prevent the areas of the retina which are devoid of oxygen from creating new, abnormal blood vessels that will impair vision in the future. Laser firing also targets leaking and bleeding vessels, and these areas are repaired. The aim of this treatment is not to improve vision but to stop the progression of retinopathy and thus prevent the total loss of vision. The most effective method of treating vision eroding macular edema is with intravitreal (intraocular) injection. This treatment involves special drugs being injected into the eye with a small needle, under operating conditions. The process is very short and the patient does not experience any pain. The patient can go home after the procedure.
Laser treatment, however, is not effective in advanced stages of diabetic retinopathy. When there is a large amount of bleeding in the eye, vitrectomy surgery is the only option. During vitrectomy, the blood inside the eye is cleaned