Characteristic feature of diabetic retinopathy: September 2005, 2010 March 2007
Ans. D: Microaneurysm Diabetic retinopathy is an ocular manifestation of systemic disease which affects up to 80% of all patients who have had diabetes for 10 years or more. Diabetic retinopathy often has no early warning signs. As new blood vessels form at the back of the eye as a pa of proliferative diabetic retinopathy, they can bleed (hemorrhage) and blur vision. On fundoscopic exam, one can see cotton-wool spots, flame hemorrhages, and dot-blot hemorrhages. Diabetic retinopathy is the result of microvascular retinal changes. Hyperglycemia-induced pericyte death and thickening of the basement membrane lead to incompetence of the vascular walls. The initial loss of pericytes leads to the formation of the dilatations of the vessels seen as microaneurysms and breakdown of the blood-retinal barrier making the retinal blood vessels more permeable. Small blood vessels in the eye are especially vulnerable to poor blood sugar control. An over accumulation of glucose and/or fructose damages the tiny blood vessels in the retina. During the initial stage, called nonproliferative diabetic retinopathy (NPDR), most people do not notice any change in their vision. Some people develop macular edema. It occurs when the damaged blood vessels leak fluid and lipids onto the macula, the pa of the retina that lets us see detail. The fluid makes the macula swell, which blurs vision. As the disease progresses, severe nonproliferative diabetic retinopathy enters an advanced, or proliferative, stage. The lack of oxygen in the retina causes fragile, new, blood vessels to grow along the retina and in the clear, gel-like vitreous humour that fills the inside of the eye. Without timely treatment, these new blood vessels can bleed, cloud vision, and destroy the retina. Fibrovascular proliferation can also cause tractional retinal detachment. The new blood vessels can also grow into the angle of the anterior chamber of the eye and cause neovascular glaucoma. Nonproliferative diabetic retinopathy shows up as cotton wool spots, or microvascular abnormalities or as superficial retinal hemorrhages. Diabetic retinopathy is detected during an eye examination that includes: Visual acuity test: Ophthalmoscopy: Note that hand-held ophthalmoscopy is insufficient to rule out significant and treatable diabetic retinopathy. Ocular Coherence Tomography or OCT: This is a scan similar to an ultrasound which is used to measure the thickness of the retina. Digital Retinal Screening Programs: This involves digital image capture and transmission of the images to a digital reading center for evaluation and treatment referral. Slit Lamp Biomicroscopy Retinal Screening Programs: Systematic programs for the early detection of diabetic retinopathy using slit-lamp biomicroscopy. Early signs of the disease (over retina): Leaking blood vessels, Retinal swelling, such as macular edema, Pale, fatty deposits on the retina (exudates) - signs of leaking blood vessels, Damaged nerve tissue (neuropathy), and Any changes in the blood vessels. Panretinal photocoagulation, or PRP (also called scatter laser treatment), is used to treat proliferative diabetic retinopathy (PDR).Rather than focus the light on a single spot, hundreds of small laser burns are made away from the center of the retina, a procedure called scatter laser treatment or panretinal photocoagulation. The treatment shrinks the abnormal blood vessels.
Hard exudate
Soft exudate
Ambylopia
Microaneurysm