Retinal Vein Occlusions
Blood and nutrient circulation to and from the surface of the retina is mostly done through one vein and one artery. If these circulatory passages or any of the smaller branches connected to them are blocked, blood flow coming into or leaving from the retina can become seriously disrupted. Blockage of one of these passages is known as "occlusion", and can result in sudden vision loss.
The retinal veins (either the Central Retinal Vein or one of its Branches) all carry blood away from the retina, and when blocked, will cause back-up of blood flow and damage to the feeding vessels behind them. Retinal vein occlusions cause: Intra-retinal Bleeding, Macular Swelling, and sometimes the growth of abnormal new blood vessels (Neovascularization) due to poor incoming blood flow (ischemia). These abnormal new blood vessels can in turn lead to: vitreous hemorrhages (floaters), tractional detachments of the retina, and forms of severe glaucoma.
Retinal vein occlusions are the second most common cause of blood vessel-related vision loss (the first is diabetic retinopathy). The condition occurs most often in men and women over the age of 50, particularly those in their 60s and 70s. Risk factors include high blood pressure, high cholesterol, diabetes, smoking, glaucoma, and, rarely, blood clotting and inflammatory conditions.
Although there is no cure for retinal vein occlusions, there are several treatment options that can address some of the eye complications that can arise from this disease. For macular swelling or edema, use of Lucentis™, focal laser treatment, and/or the off-label use of Avastin™ may help treat this complication and in certain cases improve vision but only in the right group of patients. Injectable treatments are often chronically needed and a regimen of every 4 week injections of Lucentis or Avastin may be needed to control the leakage of fluid into the macula. We are pleased to offer two novel FDA-approved therapies to treat vision-threatening macular edema from retinal vein occlusions. The first is Ozurdex (TM), a dexamethasone steroid implant whose main benefit may be its prolonged duration of effect. The other is Eylea (TM), which is approved for Central Retinal Vein Occlusion-related Macular Edema. At Retina & Vitreous Consultants, we pride ourselves on offering the latest cutting edge medical therapies for challenging retinal diseases such as this one.
For new blood vessel growth, use of scatter laser photocoagulation can prove critical in treating neovascularization and preventing the most serious complications of Retinal Vein Occlusions.
Floaters and Flashes
Floaters and flashes are symptoms of the eye that commonly occur as a result of age-related changes to the vitreous gel. When we are born, the vitreous is firmly attached to the retina and is a thick, gelatinous substance without much movement. But as we age, the vitreous becomes thinner and more watery, and tissue debris that was once secure in the firm gel can now move around inside the eye, casting shadows on the retina or floaters.
These changes are generally well-tolerated. In some patients, however, flashes and floaters are a more ominous sign and can appear as the vitreous suddenly pulls loose from the retina and tears the retina. Thus, anyone presenting with sudden onset of floaters and flashes of light may in fact have a retinal detachment, retinal tear, or simply a posterior vitreous detachment (PVD). A Retina specialist through a detailed exam can pick up on these problems and render emergency treatment of these problems before vision is lost.
The back of the eye is lined with a thin layer of nervous tissue containing millions of photoreceptor (light-sensitive) cells called rods and cones. This is the retina, where light rays are brought to a fine focus after travelling through the front parts of the eye. The retina, through a series of reactions, then converts the light it receives into an electrical signal that travels down the optic nerve to the back of the brain, where vision is ultimately formed. In the more posterior area of the retina lies the macula, responsible for giving us clear central vision. The macula is less than 1/4 of an inch in diameter and harbors a central depression called the fovea centralis, which gives us the most detailed and finest vision of objects or people. Lying in front of the retina rests the vitreous body or gel, a clear gel through which light is meant to pass through, undisturbed, on its way to the retina.