Diabetic Retinopathy

What is Diabetic Retinopathy?
Diabetic retinopathy is damage to the retina caused by complications of diabetes mellitus, which can eventually lead to blindness. It is an ocular manifestation of systemic disease which affects up to 80% of all patients who have had diabetes for 20 years or more.

How Does Diabetes Affect The Retina?
In eye, diabetes affects the circulatory system of the retina. The beginning stage, known as background diabetic retinopathy, the arteries in the retina become weakened and leak, forming small, dot-like hemorrhages. These leaking vessels often lead to swelling or edema in the retina and decreased vision.

The next stage is known as proliferative diabetic retinopathy. In this stage, circulation problems cause areas of the retina to become oxygen-deprived or ischemic. New, fragile, vessels develop as the circulatory system attempts to maintain adequate oxygen levels within the retina, which is called neovascularization. Unfortunately, these delicate vessels hemorrhage easily. Blood may leak into the retina and vitreous, causing spots or floaters, along with decreased vision.

In the later phases of the disease, continued abnormal vessel growth and scar tissue may cause serious problems such as retinal detachment and glaucoma.


Signs and Symptoms

1) Floaters

2) Difficulty reading or doing close work can indicate that fluid is collecting in the macula, the most light-sensitive part of the retina. This fluid build-up is called macular edema.

3) Double vision which occurs when the nerves controlling the eye muscles are affected.

Everyone who has diabetes (especially more than 10 years) is at risk for developing diabetic retinopathy, but not everyone develops it. In its early stages, you may not notice any change in your vision, but it can lead to the later, sight-threatening form of the disease.
If you experience any of these signs, see your eye doctor immediately. Otherwise, diabetics should see their eye doctor at least once a year for an eye exam which includes dilation.

Your eye doctor may diagnose retinopathy using a special test called fluorescein angiography. In this test, dye is injected into the body and then gradually appears within the retina due to blood flow. Your eye care practitioner will photograph the retina with the illuminated dye. Evaluating these pictures tells your doctor how far the disease has progressed.


What Causes Diabetic Retinopathy?

Changes in blood-sugar levels increase your risk of diabetic retinopathy, especially for long-term diabetes. Generally, diabetics don't develop diabetic retinopathy until they've had diabetes for at least 10 years, but it is not wise to wait that long to have an eye exam. As soon as you've been diagnosed with diabetes, you need to have a dilated eye exam at least once a year.

1) Non proliferative or background retinopathy (early form of diabetic retinopathy)
- High blood sugar can damage blood vessels in the retina, and when they are damaged, they can leak fluid or bleed. This causes the retina to swell and form deposits.


2) Proliferative retinopathy (later stage)
- New blood vessels grow on the surface of the retina. These new blood vessels can lead to serious vision problems because they can break and bleed into the vitreous, the clear, jelly-like substance that fills the center of the eye. Proliferative retinopathy is a much more serious form of the disease and can lead to blindness.
Fortunately, you can significantly reduce your risk of developing diabetic retinopathy by using common sense and taking good care of yourself.

• Keep your blood sugar under good control
• Monitor your blood pressure and keep it under good control, or seek appropriate care
• Maintain a healthy diet
• Exercise regularly

Treatment
Diabetic retinopathy is treated in many ways depending on the stage of the disease and the specific problem that requires attention. The retinal surgeon relies on several tests to monitor the progression of the disease and to make decisions for the appropriate treatment. These include: fluorescein angiography, retinal photography, and ultrasound imaging of the eye.

The abnormal growth of tiny blood vessels and the associated complication of bleeding is one of the most common problems treated by vitreo-retinal surgeons. Laser surgery called pan retinal photocoagulation (PRP) is usually the treatment of choice for this problem.

With PRP, the surgeon uses laser to destroy oxygen-deprived retinal tissue outside of the patient’s central vision. While this creates blind spots in the peripheral vision, PRP prevents the continued growth of the fragile vessels and seals the leaking ones. The goal of the treatment is to arrest the progression of the disease.

Vitrectomy is another surgery commonly needed for diabetic patients who suffer a vitreous hemorrhage (bleeding in the gel-like substance that fills the center of the eye). During a vitrectomy, the retina surgeon carefully removes blood and vitreous from the eye, and replaces it with clear salt solution (saline). At the same time, the surgeon may also gently cut strands of vitreous attached to the retina that create traction and could lead to retinal detachment or tears.


Patients with diabetes are at greater risk of developing retinal tears and detachment. Tears are often sealed with laser surgery. Retinal detachment requires surgical treatment to reattach the retina to the back of the eye. The prognosis for visual recovery is dependent on the severity of the detachment.