What
is a branch retinal vein occlusion?
This condition is the blockage of a vein by a clot, at the site where the artery
and vein cross. Arteries are blood vessels which carry oxygenated blood from
the heart to all parts of the body, including the retina. Veins are blood vessels
which carry deoxygenated blood from all parts of the body back to the heart.
What causes this condition?
• In 50% of patients, it is related to hypertension induced arteriosclerosis
(narrowing and hardening of the arteries.)
• It often affects people in their 50’s
and 60’s.
DIAGNOSIS
How is this condition diagnosed?
Several clinical signs found by the physician upon retinal examination support
the diagnosis of branch retinal vein occlusion. These include:
• Bleeding
• Swelling
• Engorgement of Veins
Fluorescein Angiography may be performed to confirm
the diagnosis and to evaluate the extent of the
affects of the blockage on the retina. Fluorescein
angiography is a test in which a water soluble
dye is injected into a vein in the arm. The dye
quickly passes through the circulation to the eye
and serial photographs are taken to examine retinal
circulation.
What are the possible complications associated
with this condition?
Swelling in the macula (the center of the retina,
used for central vision.) The blockage of the vein
slows the rate at which blood is able to leave
the
eye. This may cause some pooling of extra fluid in the center of the retina.
The “fluid” may be reabsorbed naturally by the body or may require
treatment with laser, medication or surgery.
A rarer, but more dangerous, complication is the
formation of abnormal new blood vessels (neovascularization)
which may grow on the iris (the colored part of
the eye) or on the retinal surface. These abnormal
vessels may bleed easily, causing further visual
loss. Once detected, they should be treated with
laser.
TREATMENT
Laser Treatment:
If vision remains blurry due to persistent swelling after the blood clears,
or if abnormal blood vessels are detected, laser may be helpful. The laser
is usually the primary treatment for macular edema. The laser is a bright,
highly focused beam of light which can seal some of the leaking vessels. A
large, multi center research study had reported the benefit of laser treatment
for patients with swelling in the macula. Patients were found to have a more
likely chance of visual improvement with laser treatment.
Kenalog Injection
Kenalog (triamcinalone is the generic name) is a medication which has been
used for many years to treat inflammation and swelling in the eye. This medication
can be given as an injection next to the eye (periocular injection), but
is much more effective if injected directly into the eye (intravitreal injection).
Sheathectomy Surgery
The site of the Branch Retinal vein occlusion can often be seen clearly on
examination. If this is the case, and if simpler treatments are not effective,
microsurgical techniques can be used to open the sheath constricting the
vein at the site of occlusion.
What type of vision can be expected to
return?
In most cases, visual acuity does eventually
improve somewhat after a branch retinal vein
occlusion (BRVO). The recovery phase involves
the natural formation
of collateral vessels by the body. Imagine the area of blockage as a road block.
These collateral vessels can be seen as a detour—a way for the blood
to avoid the “road block” and return via an alternate route. Although
many patients do experience a return of vision after a BRVO, it often is not
to the level of vision before the occurrence of the occlusion. The amount of
vision which returns depends upon the degree of blockage of the circulation
and the amount of time required for collateral vessels to develop. |
