Diabetic Retinopathy

Diabetic retinopathy is an eye condition in diabetic people that weakens the blood vessels in your retina. These blood vessels can swell, bleed, or leak fluid, resulting in vision changes or blindness. 

The condition can develop in any person who has type 1 or 2 diabetes and a history of high blood pressure levels. While diabetic retinopathy starts only with mild vision problems, it can eventually lead to blindness. It is the most common cause of loss of vision for diabetic people.

Diabetic retinopathy is the result of high blood sugar due to diabetes. Over time, having too much sugar in your blood can cause damage to your retina. Diabetes damage the blood vessels all over your body. The damage to your retina starts when blood sugar blocks the tiny blood vessels that nourish the retina. As a result, your eyes grow new blood vessels that do not work properly and can leak or bleed easily. 

Usually, no symptoms are experienced in the early stage of the condition. However, the symptoms may become severe and notable as it progresses through different stages. The symptoms of diabetic retinopathy include:-

1. Blurred or distorted vision
2. Streaks or small dark spots (eye floaters) in your vision
3. Holes or empty areas in your vision
4. Colour blindness
5. Night blindness (poor vision at night)
6. Trouble reading or driving

If you have type 1, type 2, or gestational diabetes, you may get diabetic retinopathy. The longer you have diabetes, the greater are the chances of developing this eye condition. Other risk factors of diabetic retinopathy include:-

1. Uncontrollable blood sugar
2. Pregnancy
3. Tobacco use
4. Hypertension 
5. Hyperlipidemia (high cholesterol)
6. Native Americans, Hispanics, and African Americans

Your eye doctor (ophthalmologist or optometrist) can diagnose diabetic retinopathy during a simple eye exam. In the test, known as pupil dilation, the doctor uses eye drops to make your pupils wide, allowing him/her to look for:-

1. Abnormal blood vessels
2. Growth of new blood vessels
3. Swelling
4. Scarring
5. Bleeding in the centre of the eye
6. Damage to the nerve tissue
7. Visual acuity
8. Peripheral vision
9. Intraocular pressure
10. Eye muscle function

After dilating your eyes, the doctor may also perform a fluorescein angiography test. During the test, the doctor injects a dye into a vein in your arm. When the dye reaches your eyes, the doctor will be able to see images of your blood vessels in the retina. These images will help him/her examine blood vessels that are broken, leaking, or closed. 

Optical Coherence Tomography (OCT) is another test your doctor may perform to diagnose diabetic retinopathy. It is a noninvasive imaging test used to obtain high-resolution cross-sectional images of your retina. The doctor measures the retinal thickness for early detection and diagnosis of diabetic retinopathy.

There are various approaches that your doctor can suggest for diabetic retinopathy treatment. The selection of the treatment approach is based on your condition and your doctor’s opinion. 

1. Anti-VEGF Injection Therapy: Vascular Endothelial Growth Factor or VEGF is a protein that makes abnormal blood vessels grow in your retina. Anti-VEGF injection therapy uses drugs, like aflibercept, bevacizumab, and ranibizumab, that reduce the fluid build-up in your retina and reverse the growth of abnormal blood vessels. 
2. Corticosteroids: Your doctor may inject corticosteroids in your eyes to improve your vision and slow down the disease progression. 

If not treated in time, Diabetic retinopathy progresses through the following four stages:-

1. Mild nonproliferative retinopathy: This is the earliest stage where tiny blood vessels in your retina change. Tiny bulges called microaneurysms protrude from the walls of these blood vessels, leaking fluid and blood into the retina.
2. Moderate nonproliferative retinopathy: The blood vessels swell and change shape as the disease progresses to its second stage. Unable to deliver blood to the retina, these blood vessels can change how your retina looks. It can also lead to the swelling of the central part of the retina, known as the macula. 
3. Severe nonproliferative retinopathy: In this stage, your blood vessels get blocked, delivering even less blood to the retina. If the blood vessels get blocked completely (macular ischemia), it can lead to blurry vision with dark spots. There are very high chances of losing vision in this stage. 
4. Proliferative diabetic retinopathy (PDR): This is the advanced stage of diabetic retinopathy, where new blood vessels grow inside your retinas, in the jellylike fluid that fills the center of your eye (vitreous). These weak, thin vessels often bleed, resulting in scar tissue formation. The scar tissue can pull your retina away from the back of the eye (retinal detachment). It can lead to permanent vision loss.