Diabetic Retinopathy Diagnosis
Diabetic retinopathy is diagnosed during a dilated eye exam. Dilating eye drops are instilled into the eye that causes the muscles inside the eye to dilate the pupil. This will allow the eye doctor to more fully examine the retina in the back of the eye.
Types of Diabetic Retinopathy
There are two types of diabetic retinopathy.
Background on Non-Proliferative Diabetic Retinopathy
This type of diabetic retinopathy is characterized by leaking blood vessels causing fluid and blood to collect in the retina. If the fluid or blood collects in the macula, it leads to blurred or loss of vision. The macula is the portion of the retina responsible for our clear central vision for things such as watching TV, reading, etc. The amount blood and fluid that has leaked into the retina will determine the extent of the vision loss.
Proliferative Diabetic Retinopathy
Proliferative diabetic retinopathy is a more severe form of diabetic retinopathy. This means that the blood flow through the retina is poor leading to ischemia. This ischemia causes new blood vessels to grow in the retina and from the optic nerve. A growth factor is released in the retina due to the loss of blood flow which stimulates new blood vessels. These new blood vessels are fragile and can break open causing hemorrhaging in the retina and into the vitreous (jelly-like substance that fills up the back portion of the eye). This can lead to scarring in and on the surface of the retina leading to a retinal detachment. This type of diabetic retinopathy can cause severe vision loss or blindness. These abnormal blood vessels can also cause a severe form of glaucoma called neovascular glaucoma.
Diabetic Retinopathy Tests
Once your eye doctor examines the retina and sees damage in the retina from diabetes, they may tests to determine the extent of the diabetic retinopathy.
Once your eye is dilated, regular photos of the retina are usually taken to help monitor the diabetic retinopathy. They will then inject a Fluorescein dye into a vein in your arm. A series of photos are taken as the dye circulates through the retina. These are followed by a few photos several minutes later to capture images of any leaking from blood vessels in the retina. The doctor will examine these photos to see the extent of damage in the retina.
Optical Coherence Tomography (OCT)
OCT is a test in which the machine scans the retina showing fine details of the structures of the retina especially the important macular area. This can help with seeing how much fluid is in the macula without having to do a Fluorescein angiogram with injecting dye.