When blood flow through the retina is blocked or when the retina pulls
away from the wall of the eye, getting the problem properly diagnosed
can be an emergency. Modern treatments can do wonders if they are begun
before the damage is irreversible. But a delay in getting to a retinal
specialist can diminish the ability of even the best therapy to preserve
or restore normal vision.
As with all living tissue, the retina is highly dependent on a constant
supply of oxygen-carrying blood. Should anything disrupt that, vision
is at risk. Two retinal mishaps, retinal-vein occlusion and
retinal detachment, can occur at any age, but both are more common among older people.
Recognizing a Blockage
In July, David Bronson of Stone Ridge, N.Y., an avid reader at age 82,
realized that the vision in his left eye was a little cloudy. He thought
cataract was the cause, but when he saw an ophthalmologist two weeks later, he
learned that the problem was more serious: a partial blockage in the central
vein that drains blood from the retina.
The blockage caused pressure to build in the capillaries that take blood
to the retina, which then leaked into the center of the eye, clouding
Mr. Bronson's vision. The blockage and its consequences are analogous
to a clogged sink drain; if water keeps running into the sink, it will
eventually spill over the top.
Retinal-vein occlusion is a common cause of vision loss in older people,
second only to
diabetic retinopathy as a blood vessel disorder of the retina, according to
a report last year in The New England Journal of Medicine.
Unlike Mr. Bronson's experience, retinal-vein occlusion most often
involves a branch vein, which is less serious and in half of cases resolves
on its own within six months. If treatment is needed, most, though not
all, patients respond well to laser therapy, the journal authors reported.
Central retinal-vein occlusion can cause
swelling of the macula and loss of central vision. So Mr. Bronson is being treated
with monthly injections into his eye of Lucentis, a drug recently licensed
for this condition. Injections of
steroids into the eye are also often effective.
The article authors, Dr. Tien Y. Wong of the National University of Singapore
and Dr. Ingrid U. Scott of Penn State Hershey Eye Center, noted that retinal-vein
occlusion occurs in one or two people in 100 older than 40, most often
because of a clot and
atherosclerosis, a hardening of retinal arteries that puts pressure on a retinal vein.
High blood pressure, Mr. Bronson's only other health problem, is the leading risk factor
for this disorder, but retinal-vein occlusion is also associated with
diabetes, elevated blood
lipids, smoking, kidney disease and
Typically, patients develop sudden painless vision loss in one eye. The
extent of vision loss depends on how much of the retina is affected and
whether the macula is involved. Most of the time, the diagnosis can be
made based on a clinical exam, although a test called fluorescein
angiography is often performed to assess the severity.
Retinal detachment, which occurs in about 18 out of 100,000 people a year,
is much less common than retinal-vein occlusion but more likely to cause
permanent vision loss if not promptly treated. The longer the retina remains
detached, the less likely vision can be restored, so it is vital to recognize
the symptoms and seek an ophthalmologist's care without delay.
Retinal detachment is painless but nearly always causes symptoms, often
before the detachment starts: a sudden appearance of many "floaters"
- spots, hairs or strings - in your vision; sudden brief flashes of light
even when your eyes are closed; or a shadow over part of your visual field.
Donald Distasio of Syracuse was 61 when, he said, "I started seeing
floaters and blurriness in the inner corner of my right eye." His
optometrist correctly suspected a retinal detachment and immediately sent
Mr. Distasio to a retinal surgeon, who explained that the vitreous gel
in the center of his eye had pulled on the retina, causing it to tear.
Retinal holes or tears can also result from thinning of the retina with
advancing age or from other eye diseases. Once the retina tears, vitreous
fluid can leak behind it and push it away from the wall of the eye, preventing
images from reaching photoreceptor cells and, ultimately, the brain. The
result is a vision blackout of the affected part of the retina.
In addition to age, risk factors for retinal detachment include extreme
nearsightedness, a family history of the problem, a prior detachment in one eye,
cataract surgery and a severe eye injury, as can occur in an auto accident or from a paint
ball, a BB gun or a bungee cord, said Dr. Donald J. D'Amico, chief
of ophthalmology at Weill Cornell Medical College and NewYork-Presbyterian Hospital.
In an interview, he outlined
the usual treatments. The simplest, called
pneumatic retinopexy, can be done in the doctor's office under local
anesthesia. A gas bubble is injected into the vitreous cavity. As the gas expands,
it presses the retina against the wall of the eye and closes the break.
The patient must remain face down for most of several days to weeks to
keep the bubble in the right place. The retinal break is often permanently
sealed with a freezing probe or laser.
Another common treatment is scleral buckling, done in a hospital under
anesthesia but usually on an outpatient basis. A permanent silicone band
is sewn to the outside wall of the eyeball, creating an indentation that
presses the retina back in place.
A third technique, vitrectomy, is also done in a hospital. The vitreous
gel that is pulling on the retina is removed and replaced with gas or
liquids that reattach the retina. The procedure is sometimes combined
with scleral buckling.
After treatment, it can take many months for vision to improve. The treatment
itself may also cause a cataract, requiring further surgery.