Damage to the Lens & Optic Nerves Increases Vision Loss Risk
We don't know the exact mechanism, but there is thought to be a somewhat greater risk of cataracts and glaucoma in patients with diabetes, says Lloyd Paul Aiello, M.D., Ph.D., professor of ophthalmology at Harvard Medical School and director of the Beetham Eye Institute at the Joslin Diabetes Center. Researchers have suggested that excess levels of sorbitol, a sugar formed from glucose, can trigger the formation of cataracts—a clouding of the lens—in people with diabetes.
If these cloudy deposits cause vision impairment, the lens may have to be removed surgically and replaced with an implant. Cataracts sufferers are often pleasantly surprised at how much clearer their vision is with the newly implanted lens.
Abnormally high pressure within the eyeball can cause a condition called glaucoma, where pressure damages the optic nerve that carries images from the retina to the brain. Your ophthalmologist tests you for glaucoma regularly because irreversible damage can be done to the optic nerve before you notice any symptoms. Medicated eye drops often help reduce intraocular pressure, but more serious cases of glaucoma may require surgery.
Other Risk Factors for Vision Loss
Other possible risk factors for diabetic retinopathy include elevated levels of cholesterol and triglycerides and high blood pressure (hypertension). While the early stages of diabetic retinopathy often have no symptoms, bleeding in the vitreous humor can cause blurred vision, distorted vision, floaters (small, dark clouds in the vision field) and flashers. Sudden bleeding in the vitreous humor can cause vision loss; retinal detachment can cause wavy vision, a dark shadow in the vision field or sudden vision loss.
From our sister publication, Diabetes Focus (Spring 2011)