An estimated 5% of the Australian population have some type of diabetes. However, this prevalence is considered to be an underestimation as many Australians live with undiagnosed diabetes; experts estimate this rate to be around 1 undiagnosed diabetic for every 4 adults with known diabetes. Diabetes, also known as diabetes mellitus, is a metabolic disease involving a deficiency in the production and/or function of the hormone insulin. This results in an elevated concentration of glucose (sugar) in the bloodstream, which damages the blood vessels throughout the body as well as the organs and other anatomical structures that are dependent on this blood supply.
Diabetes-related complications include:
- Increased risk of a heart attack
- Increased risk of a stroke
- Reduced blood flow to the feet and legs, resulting in peripheral arterial disease
- Diabetic kidney disease
- Dental problems
- Damage to the nerves throughout the body
- Increased risk of eye disease, including diabetic retinopathy
The retina is the sensory tissue lining the inside of the back of the eyeball and is responsible for detecting light and forwarding these signals onto the brain for the perception of vision. Throughout the retina and surrounding anatomical structures are many tiny blood vessels that help to support the high energy activities of this part of the eye. Elevated blood glucose levels have the potential to damage these retinal blood vessels, resulting in an eye disease known as diabetic retinopathy.
There are two broad categories of diabetic retinopathy – non-proliferative and proliferative. During the non-proliferative stage of the disease, an ophthalmologist or optometrist examining your retina may detect signs such as:
- Tiny haemorrhages or yellowish deposits called exudate throughout the retina due to leaking damaged retinal blood vessels
- Areas of swelling known as oedema in the retina, also due to leakage of fluid from damaged vessels
- Areas of whitening known as ischaemia, due to restriction of blood supply to that part of the retina
- Other visible changes to the blood vessels throughout the retina
If the case of advanced diabetic eye disease, proliferative diabetic retinopathy is diagnosed by observing the formation of new blood vessels in the retina. Because these new vessels are fragile and poorly formed, they are at risk of causing a large haemorrhage in the eye, which may fully or partially obscure your vision. Though vision loss directly from a haemorrhage may be temporary until the blood can be cleared, the presence of new blood vessels may also result in further complications such as retinal scarring and distortion, a retinal detachment, or glaucoma. Proliferative diabetic retinopathy always requires treatment, typically in the form of retinal surgery.
Diabetic Retinopathy Treatment
In the milder stages of retinopathy, you may have few or no symptoms at all and diabetic retinopathy treatment is not warranted. Those early signs of diabetic eye disease can be managed by good overall diabetes control. However, if you develop fluid swelling around your macula, which can occur even in the non-proliferative stages, you will notice a blur or distortion to your central vision as we are most aware of this part of our field of view. Depending on the severity of the swelling, your eye doctor may recommend simply monitoring your retina and allowing time for the swelling to self-resolve, or may recommend diabetic retinopathy treatment in the form of laser retinal surgery or eye injections to protect the vision and prevent further retinal damage.
Laser retinal surgery aims to seal off leaking blood vessels in a process known as photocoagulation. In a way it can be thought of as applying laser burns to select areas of the retina to weld closed the damaged blood vessels. Laser retinal surgery may also be used to reduce the trigger for new vessel growth during proliferative retinopathy by deliberately burning and scarring areas of retinal tissue, thereby reducing the oxygen demand of that part of the retina. Though there may be some loss of peripheral vision from this treatment, it helps to preserve the rest of your sight, particularly your crucial central vision.
Medical diabetic retinopathy treatment in the form of eye injections is also used in cases of macular swelling or proliferative retinopathy. The medications used are often a class of drug known as anti-VEGF (vascular endothelial growth factor), which work by blocking the chemicals released by the tissues of the eye that stimulate the growth of new blood vessels.
In the case of a very large haemorrhage inside the eye as a result of proliferative retinopathy, your eye surgeon may recommend a procedure known as a vitrectomy, which involves the complete removal of the vitreous gel that usually takes up the space in the back half of the eyeball. By removing the vitreous, the blood obscuring the retina can also be cleared, restoring your vision.
Other complications as a result of diabetic retinopathy need to be treated as they arise. In the case of a retinal detachment this requires retinal surgery; in the case of glaucoma your ophthalmologist may discuss with you a number of appropriate treatments, such as eye drops or glaucoma surgery. People with diabetes are also at a greater risk of developing cataracts, which are treated with surgical removal.
People with diabetes are encouraged to have regular eye tests with their optometrist or ophthalmologist, even if your vision seems normal. Even moderate non-proliferative diabetic retinopathy can occur in the absence of any noticeable symptoms, but to an eyecare professional this can help to signal that your overall diabetes control needs to be revised.
The best way to avoid needing any sort of diabetic retinopathy treatment is to manage your diabetes well from the beginning, whether that’s with diet or medications as advised by your GP, diabetes educator, or endocrinologist.
Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.