Blind Dogs Can See After New Treatment for Sudden Onset Blinding Disease
Iowa State University veterinary researchers may have found a cure for a
previously incurable disease that causes dogs to go blind suddenly. They have
successfully treated two dogs for sudden acquired retinal degeneration
syndrome (SARDS). The dogs were treated with intravenous immunoglobulin
(IVIg).
If two dogs are any indication, Iowa State University veterinary researchers
may have found a cure for a previously incurable disease that causes dogs to
go blind suddenly.
In the past six weeks, two dogs have been successfully treated for sudden
acquired retinal degeneration syndrome (SARDS) by a research team led by ISU
veterinary ophthalmologist Dr. Sinisa Grozdanic in the College of Veterinary
Medicine.
The experimental treatment is the first to reverse blindness and restore sight
to dogs diagnosed with SARDS. The treatment restored sight to the two dogs
that were treated on April 12 and April 27.
"This is the first small sign of hope that actually something can be done,"
Grozdanic said.
The dogs were treated with intravenous immunoglobulin (IVIg), a human blood
product that contains antibodies from the plasma of thousands of blood donors.
It is used to treat immune deficiencies, inflammatory diseases and autoimmune
diseases.
"Although the dogs won't be catching any Frisbees, they can navigate and not
bump into objects," Grozdanic said.
SARDS was first identified in the 1980s and blinds as many as 4,000 dogs each
year in North America, he said. The dogs have a sudden loss of vision despite
no structural changes to the eyes or damage to the retinas in the early stages
of the disease. Their eyes appear completely normal, but their retinas show no
electrical activity.
Grozdanic and his colleagues wanted a better understanding of the molecular
mechanisms that cause SARDS. They worked with the University of Iowa's
Department of Ophthalmology and Vision Sciences to conduct genetic testing of
SARDS tissue, cross referencing the results with the U of I's datebase of
genetic information from different human ocular diseases.
"We saw that the molecular profile of SARDS eyes is very similar to immune
mediated retinopathy in humans, which is usually antibody induced. That was
the key factor," Grozdanic said.
Immune-mediated retinopathy in humans was not treatable until about 10 years
ago when IVIg was found to show results in some patients.
Although the treatment has worked in two SARDS dogs, not every dog is a good
candidate, Grozdanic cautions. Dogs with severe cardiac or kidney disease
cannot tolerate IVIg. And it won't work in a dog whose retina degeneration is
advanced.
"Once a dog gets SARDS, the retina degenerates quickly, so it's important the
dog is treated with IVIg very soon after diagnosis," he said. "Usually dogs
that have SARDS for longer than two months have severe retinal changes. The
sooner it's treated, the better chance it will work."
An optical coherence tomography scan is needed to confirm the condition of a
dog's retina. Iowa State University's Veterinary Medicine Hospital is the only
veterinary institution using this advanced diagnostic technology, which is
more commonly found in large ophthalmology centers for humans.
Diagnostic tests cost about $700. If the dog is a good candidate for
treatment, hospitalization and intensive care fees will be about $1,200. The
IVIg cost will be between $35-40 per pound of the dog's body weight.
"At this point, the biggest unknown is how long the treatment will last. It
could be anywhere from a few weeks to a few years," Grozdanic said.
Grozdanic recommends owners visit the nearest veterinary ophthalmologist as
soon as a dog exhibits any loss in vision.
Information About SARDS (Sudden Acquired Retinal Degeneration Syndrome)
