Retinal vein occlusion is a condition of the eye that may cause partial or total vision loss, although it may be asymptomatic. It is caused by a blockage in the primary vein that drains blood from the retina, or a smaller branch of this vein.
Different eye care professionals treat this condition differently, but some medications and surgical procedures are routinely used to treat or prevent further eye-related complications.
The prognosis for retinal vein occlusion depends on the subtype of occlusion that is present, but patients are typically monitored for potential complications.
What Is Retinal Vein Occlusion?
The eye has only one vein with multiple branches, and when that vein or one of the branches is blocked, blood flow backs up and stagnates. Without regular blood flow, the cells in the retina may start to die. A retinal vein occlusion will impair sight in the affected eye and can eventually cause permanent damage.
Symptoms Of Retinal Vein Occlusions
The symptoms of a retinal vein occlusion can be easy to miss at first because in some cases there may be no symptoms. Symptoms usually appear only in one eye.
They can be subtle, but they may progress quickly, in some cases causing secondary glaucoma that can lead to severe pain and a complete loss of vision.
Symptoms may come on suddenly, or they may be mild at first, becoming more pronounced over the course of several hours or days. Symptoms of a retinal vein occlusion can include:
- Pain in the eye from increased eye pressure brought about by secondary glaucoma
- Blurred vision
- Loss of side vision
- Visual distortions
- Symptoms that worsen in hours or days
What Can Cause A Retinal Vein Occlusion?
A retinal vein occlusion can happen to anyone, but it is more common in people who are over the age of 65 or who have certain medical conditions (only about 15 percent of cases occur in people who are age 45 or under).
In some cases, if the vein in the eye is too small or narrow, it can contribute to the development of a retinal vein occlusion.
Hyperhomocysteinaemia, lupus anticoagulant antibodies, anticardiolipin antibodies, or inherited blood clotting disorders are rare causes and appear to be more common in younger patients (under the age of 45) who develop retinal vein occlusion.
As many as 64 percent of patients with retinal vein occlusion may have hypertension (high blood pressure). Some of the other health conditions associated with a retinal vein occlusion include trauma to the eye, diabetes, secondary glaucoma, and high cholesterol.
What Are The Various Types Of Retinal Vein Occlusion?
Health professionals subdivide retinal vein occlusion into ischemic and nonischemic forms, but this classification is still controversial. Ischemic blockages have more pronounced symptoms of pain and vision loss.
A central retinal vein occlusion is diagnosed when the blockage occurs at the point of the optic nerve. In most cases, this type of occlusion is accompanied by a loss of vision in one eye, without pain. Vision may be constantly blurry, or the blurriness may come and go.
The nonischemic form of this occlusion may manifest only subtle symptoms. The ischemic form may be accompanied by a more dramatic loss of vision.
When the blockage is at a branch in the retinal nerve, it is classified as branch retinal vein occlusion. This type is more common, and may include any branch in the vein. Symptoms and prognosis will depend on whether a minor or a major branch of the vein is affected.
In some cases, there may be no symptoms at all, but in other cases there could be slightly blurry vision or a blind spot. A small blockage may not cause any symptoms at all, but a large blockage could be associated with loss of vision.
How Is Retinal Vein Occlusion Treated?
In many cases, a retinal vein occlusion is an emergency situation. Consultation with a retinal specialist is typically necessary for proper diagnosis.
There is no universally agreed-upon treatment for retinal vein occlusion. In some cases, the patient is monitored for further complications. Several other conditions may result from a retinal vein occlusion, and some of these require prompt treatment.
Often, the blockage is associated with swelling of the retina in the central, or “macular” region (macular edema), which can cause blurring of the central vision.
This is frequently addressed with laser treatment or injections of medications such as bevacizumab (Avastin), ranibizumab (Lucentis), or steroids (triamcinolone or dexamethosone), which can help reduce or eliminate this swelling.
Rarely, a retinal vein occlusion may lead to abnormal growth of blood vessels that can cause bleeding or can clog the fluid drainage channels in the eye, which can lead to elevated eye pressure (secondary glaucoma).
This may require more extensive laser treatments, anti-VEGF injections, eye drops, or even surgery to lower the eye pressure.
More controversial methods for treating vein occlusions may include heparin (dalteparin), vitrectomy (removing the vitreous jelly from the back of the eye), radial optic neurotomy (incisions in the sheath of the optic nerve), or hyperbaric oxygen
What Is The Usual Prognosis For Retinal Vein Occlusion?
In some cases, vision may improve spontaneously orafter treatment, but frequently a retinal vein occlusion does lasting damage. The degree to which the patient will recover his or her vision is largely dependent on whether the occlusion was ischemic or nonischemic.
The prognosis for nonischemic cases is variable, but fewer than 10 percent of ischemic patients recover their vision completely. Other cases may see no improvement in sight, and some may go on to develop another occlusion.
Other complications may occur as well, so patients with this condition should be monitored beyond the resolution of the initial occlusion. Complications that may occur with ischemic retinal vein occlusion include secondary glaucoma (high intraocular eye pressure) and macular edema (swelling in the retina).
Symptoms such as blurry vision, eye pain, or visual disturbances should be reported to a physician right away. In case of sudden vision changes and pain, a trip to an eye care professional might be the best course of action.
An eye care professional should be consulted for a definitive diagnosis of retinal vein occlusion. After the diagnosis is made, patients should be monitored and treated for any complications.