Primer on Diabetic Retinopathy

If you pool everyone with diabetes together and form a nation, they would be the third most populous country in the world.

Those with diabetes will normally find that they have increased levels of glucose in their blood. This can lead to nerve and blood vessel damage as well as an increased risk of cancer due to DNA harm.

Although, not everyone with diabetes will experience sight loss, diabetics will have a higher risk of developing certain visual impairments, such as cataracts and glaucoma.

One of the more common ones is diabetic retinopathy.

This is when the increase in blood sugar levels affect blood vessels at the back of the eye. This interferes with how the retina work and can lead to retinal vessels leaking or bleeding.

 

There are 4 main stages of diabetic retinopathy:

1. Background Retinopathy

This is when capillaries in the retina weaken and develop small areas of swelling. This can lead to small amounts of bleeding as well as the leaking of a fluid called exudate. Although this will normally not affect vision, if it is left untreated the condition can become worse and cause the condition to the next stage.

 

2. Non-Proliferative Retinopathy

Here we see more drastic damage to the capillaries in the retina and usually occurs after years of high blood sugar levels. Bleeding and leaking is more prominent and blood vessels are weakened, potentially losing the ability to transport blood which can cause the retina to malform. Eventually, blood vessels may be completely blocked, which will prompt the body to release growth factors to encourage the formation of new vessels.

 

3. Proliferative Retinopathy 

By now, new blood vessels have been formed to help supply blood. However, they are weak and are prone to haemorrhaging and leaking. They can also grow on the retinal surface or inside the vitreous gel. When blood or fluid is leaked, this can damage the retina or block vision when inside the vitreous gel. Scarring can also occur and an increase in scar tissue can cause the retina to detach which may lead to serious sight loss.

 

4. Diabetic Maculopathy

The more common cause of serious sight loss, diabetic maculopathy can occur with or without proliferative retinopathy [Pipe, D.M. & Rapley, L.J. (2008). “Abnormal Ocular Conditions: A Handbook for Dispensing Opticians”]. It occurs when haemorrhaging or leaking involves the macular area of the eye and can cause central vision loss.

 

Symptoms of diabetic retinopathy may not occur at the beginning and can start to appear as the condition advances. Typical manifestations include:

  • Blurred vision
  • Dark spots or patches
  • Eye pain or redness
  • Reduction in night vision
  • Sudden sight loss

Treatment for diabetic retinopathy can depend on how far it has progressed. Laser surgery can be done on a localised area to help reduce swelling and seal up blood vessels. For larger affected areas, pan-retinal laser surgery can be used to shrink abnormal blood vessels and inhibit the release of growth factors. Vitrectomies are used to treat severe bleeding into the vitreous gel. Vitreous is removed and replaced with a clear salt solution to maintain the pressure in the eye.

However, these treatment methods are more aimed at preserving sight rather than restoring. As with many diseases, prevention is just as (if not more) important as treatment. Maintaining a manageable blood sugar level is key and this includes exercise, diet, and generally living a healthy lifestyle.