Cystoid Macular Edema (CME) usually
occurs due to ocular inflammation. The inflammation within the
eye produces chemicals which cause the retinal vessels to leak.
This results in fluid accumulation in the central retina, and
the formation of small retinal cysts. CME due to inflammation
can occur in uveitis (inflammation of the inner lining of the
eye) or following eye surgery. CME can also be caused by
mechanical irritation of the retina as occurs in an epiretinal
membrane. (See previous page for more information about
epiretinal membrane)
Symptoms of CME
CME usually causes a decline in central
vision. Visual acuity may range from 20/20 to 20/400.
Distortion of images and decreased color vision may also be
present. Peripheral vision is normal.
Diagnosis of CME
In addition to a dilated eye exam, a test
called Fluorescein Angiography may be required. During this
test a dye is injected into a vein in the arm. Special photographs
are taken of the retina as the dye passes though the eye. Leakage
and accumulation of dye into cystic spaces becomes apparent to the
physician.
Treatment of CME
In most cases, treating CME involves treating
the underlying inflammation. The first line of treatment for CME is
usually non-steroidal, and steroid eye drops. The second line of
treatment included oral steroids or other systemic anti-inflammatory
agents, or an injection of a steroid next to or into the eye.
Finally, if the vitreous gel is thought to be contributing to the
inflammation, it can be removed by performing vitrectomy surgery.
If CME is caused by an epiretinal membrane, surgical removal of the
membrane may be indicated.
Importantly, CME occurs in some people following cataract surgery,
even if the surgery itself is perfect. CME following cataract
surgery is usually not severe, and the majority of cases respond to
treatment and resolve within 6 months. |