Diabetes and vision loss
Diabetes occurs because the pancreas cannot produce insulin and/or the body cannot use insulin properly. This causes high levels of blood glucose, or sugars, that need to be managed to prevent serious health conditions. The build-up of glucose can affect everything from the eyes to the feet.
Understanding diabetic eye disease
The ophthalmic complications of diabetes are the leading cause of blindness among adults aged 20 to 74 years. Diabetic retinopathy (DR) is a condition occurring in persons with diabetes, which causes progressive damage to the retina, the light sensitive lining at the back of the eyes.
DR occurs when blood vessels are damaged because of diabetes. This affects the retina, tissue at the back of the eye, and the macula, part of the retina that enables you to see fine details clearly. High levels of blood glucose can weaken, damage, or block the blood vessels in the retina, preventing the retina from receiving enough blood or oxygen.
DME is associated with swelling or thickening of the retina and leaking of blood and fluid into the macula, a small area in the back of the eye that allows for sharpness of vision. This sets a number of processes into motion, including triggering high levels of vascular endothelial growth factor, called VEGF. Excess VEGF contributes to leaky blood vessels and ultimately causes the macula to swell and thicken.
Swelling of the macula reduces the clarity or sharpness of vision at a distance and blurs sight. If left untreated, it can lead to severe and even permanent vision loss.
Description: A three-part picture is drawn. Part one is a picture of a man performing an insulin test on himself. Part two shows a blood vessel with sugar in the blood stream. The blood vessel walls are animated to show two ruptures. Part three is a picture of an eye with the blood vessels showing.
Narration: Diabetes is a common disease that interferes with the body’s ability to use and store sugar. Too much sugar in the blood can damage the blood vessels in your body including the tiny blood vessels in the retina.
Description: A picture of a cross section of an eye is drawn showing the retina.
Narration: The retina is a light-sensitive layer at the back of the eye that acts like the film in a camera.
Description: A picture of a colourful butterfly is drawn in front of the eye, with a brain shown behind the eye to show that signals of the view of the butterfly are being sent to the brain.
Narration: It captures the images taken by the eye’s lens and sends the images as signals to the brain.
Description: A picture of a damaged blood vessel.
Narration: The damage to the blood vessels in the retina is called diabetic retinopathy and it is a leading cause of vision loss in North America.
Description: A cross section of an eye is drawn with a zoom into one section showing a blood vessel that is damaged. As the script progresses, VEGF is shown around the blood vessel and new small blood vessels are drawn growing from the main blood vessel.
Narration: The blood vessel damage can cause vision loss in several ways: When blood vessels are blocked or damaged, the tissues in the eye increase the production of proteins called growth factors such as “vascular endothelial growth factor”, or VEGF, to stimulate the growth of new blood vessels.
Description: The new blood vessels are shown to be bleeding.
Narration: However, these new blood vessels are abnormal and fragile and can bleed into the eye.
Description: The new blood vessels are shown to be leaking fluid into the retina.
Narration: The eye’s blood vessels may also leak fluid into the retina
Description: The macula is shown on the cross sectional picture of the eye and a picture of a man looking straight ahead is shown.
Narration: …and, more problematically, into the macula which is the central part of the retina where sharp, straight-ahead vision occurs.
Description: A picture of a woman testing her insulin level is superimposed on the other pictures and as the script talks about blindness, dark sunglasses are added to her face.
Narration: When the leaking fluid causes swelling of the macula in a person with diabetes it is known as Diabetic Macular Edema or DME and it is a serious eye complication that can cause severe vision loss or blindness.