Occlusion (blockage) of a retinal vein is a common cause of sudden painless reduction in vision in older people.
The retina is the thin membrane that lines the inner surface of the back of your eye. Its function is similar to that of the film in a camera. Blockage of one of the veins draining blood out of the eye causes blood and other fluids to leak into the retina, causing bruising and swelling as well as lack of oxygen. This interferes with the light receptor cells (cells responsible for vision) and reduces vision.
The condition is uncommon under the age of 60 but becomes more frequent in later life.
It causes painless loss of vision, In general, visual loss is more severe if the central retinal vein is blocked.
A blockage forms in the vein, usually due to a blood clot, and obstructs the blood flow. The exact cause is unknown, but several risk factorsmake the condition more likely. These include
The complications of RVO, especially if they are not treated, can lead to irreversible loss of vision
Since there is no cure for either BRVO or CRVO, the focus of management is on the following: The evaluation and treatment of underlying risk factors (e.g., diabetes or hypertension), leading to improved treatment of systemic problems and prevention of heart attack and stroke. The evaluation and treatment of complications such as macular edema and neovascularization, leading to preservation of vision.
Two medications currently being used, Lucentis® / Accentrix (ranibizumab) and Avastin® (bevacizumab), have both been successful in reducing the edema and improving vision in both BRVO and CRVO. A third medication, Eylea® (aflibercept), is effective for treating edema secondary to RVO.
A common treatment approach is to start with 2-3 monthly injections and continue as needed over the next several months.
Complications are rare, but can include a) infection (endophthalmitis) b) retinal detachment and c) vitreous hemorrhage, all of which are related to the injection itself and not specifically to the medications.
Although only Lucentis and Eylea are approved by the FDA for treatment, Avastin is also commonly used in this manner, and all are thought to be effective and equally safe for the eye.
Steroids: Steroids are another type of medication that can decrease macular edema. Similar to Lucentis, Eylea and Avastin, the steroid is injected directly into the vitreous through the sclera. Two of the most commonly used steroids are preservative-free Triamcinolone Acetonide Suspension and Ozurdex (a dexamethasone implant). The primary difference between them is that the effect of Ozurdex is longer in the eye than triamcinolone (6 months versus 2 months). The complication of steroid induced glaucoma and cataract progression is much more with thriamcinolone than Ozurdex.
Repeat injection are required frequently over the course of the disease.
Laser photocoagulation: Laser is the best way to control and decrease neovascularization in either BRVO or CRVO. A stronger laser is applied to the affected region of the retina. Mild peripheral vision loss can sometimes occur.
Vitreous hemorrhage and tractional retinal detachment:If the retina specialist is unable to perform the laser treatment due to either a vitreous hemorrhage or retinal detachment, a vitrectomy will be recommended. A vitrectomy is an outpatient surgical procedure performed in an operating room that involves removal of the vitreous from the inside back of the eye through three openings made in the sclera using a microscope and several small instruments. Now a days Micro incision sutureless vitrectomy (MIVS) is done using 25 and 27 Gauge instruments
Treatment includes control of Intraocular pressure (IOP) via topical, oral and systemic medications. Also it is required to treat the underlying retinal disease which is causing tremendous amounts of VEGF via PRP laser, AntiVEGF injections and Cryopexy. In some cases antiglaucoma surgery in form of Trabeculectomy with MMC or Valve surgery is required.
As with any treatment, it is critical that patients have a thorough discussion with their retina specialist regarding all of the treatment options, including the risks, benefits and alternatives, before deciding the appropriate course of action.