The Impact of Diabetes on the Eyes
Diabetes is a chronic disease that occurs either when the pancreas is unable to produce enough insulin or when the body cannot effectively use the insulin that it produces. Diabetes is of two types. Type 1 diabetes, also known as childhood-onset diabetes, is characterised by inadequate insulin production. The only treatment is the daily administration of insulin. The causes and methods of prevention of Type 1 diabetes are as yet unknown. Type 2 diabetes, the far more common form, results from the body’s inability to effectively use insulin. Insulin is a hormone that regulates blood sugar. If not treated, diabetes leads to high levels of glucose in the blood, which can harm many of the body’s systems and organs, including the nerves, blood vessels, heart, kidneys, eyes and so on.
Global Incidence of Diabetes
According to the World Health Organisation, 422 million people worldwide had diabetes as of 2014. The global prevalence of diabetes among adults over the age of 18 rose from 4.7% in 1980 to 8.5% in 2014. The spread of diabetes has become more rapid among the middle and lower income countries. Diabetes was the direct cause of 1.5 million deaths in 2012; another 2.2 million deaths in 2012 were attributable to high blood sugar levels. Diabetes is a major cause of kidney failure, heart attacks, strokes, lower limb amputation and blindness. Diabetic retinopathy, one of the complications from diabetes, causes 2.6% of the cases of global blindness.
What is Diabetic Retinopathy?
As explained by an article on the nhs.uk website, diabetes can affect the eye, more specifically the retina. The retina, located at the back of the eye, is composed of a layer of light-sensitive cells that convert light into electrical signals, which are sent to the brain, which in turn converts these signals into the images we see. The retina has a constant supply of blood via a network of tiny blood vessels. Persistently high blood sugar levels can damage these blood vessels in three main stages, which are as follows.
- In the first stage, tiny bulges develop in the blood vessels, which may bleed slightly. There is usually no impact on vision yet. This stage is called background retinopathy.
- There are more significant and widespread changes in the blood vessels, including much more bleeding into the eye. This is the stage of pre-proliferative retinopathy.
- Scar tissue and new blood vessels, which are weak and bleed easily, develop on the retina, which can result in some loss of vision. This stage is known as proliferative retinopathy. The scar tissue can cause the retina to detach from the back of the eye. If the new blood vessels interfere with the normal flow of fluid from the eye, pressure may build up, which can damage the optic nerve, resulting in glaucoma.
Early Detection is Key
According to research published on the ncbi.nlm.nih.gov website, early retinal changes are unfortunately not noticed by patients. Visually threatening changes on the retina develop over time in up to 50% of those with Type 1 diabetes and 30% of those with Type 2 diabetes. For example, if not treated immediately, retinal detachment can lead to sudden and permanent vision loss. Other complications from proliferative retinopathy can lead to blindness over time.
Regular Visits to a Retina Specialist are Very Important
For those with diabetes, a yearly visit to the retina specialist is strongly recommended, as an article on mayoclinic.org states. Only clinics specialising in retina treatments will have the necessary equipment for required tests for diabetic retinopathy, such as optical coherence tomography and fluorescein angiography, and for laser treatments and operations such as vitrectomy. Diabetic retinopathy is a serious complication, but it can be delayed by good blood sugar control, and can be treated if diagnosed early by regular annual visits to the retina specialist.