Preproliferative diabetic retinopathy is a more advanced stage of damage to the eye than the early signs found in BDR. Once this stage is present, vision can worsen rapidly if the progression of damage is not monitored regularly and treated when it progresses to a certain stage. Changes to the eyes are documented with either retinal photographs or with a more precise fluorescein angiography test. In this test, fluorescein dye is injected into a blood vessel in the arm and photographs are taken of the retina to look for leakage of fluorescein dye from damaged blood vessels. Changes in this stage include:
Intraretinal Microvascular Abnormalities (IRMA): these are irregularly-shaped blood vessels that appear in a localized area of the retina as squiggly lines through an ophthalmoscope. They signify irregular dilation of retinal blood vessels in response to poor blood circulation.
Cotton Wool Spots: these are seen as pale white areas in the retina where blood vessels have become blocked and localized areas of nerves have been damaged.