Golden Retriever Update - Summer 2022 - 3

GOLDEN RETRIEVER Update
From left: 1) In this severely affected GRPU eye, the white wispy fibrin-like material within the eye increases the risk
for glaucoma, and the brown areas that look like sprockets on a gear show posterior synechia, where the iris adheres to
the lens. 2) The classic radial pigment of GRPU that looks like spokes on a wheel is evident in this eye. 3) The multiple
uveal cysts seen in this eye increase the risk for GRPU.
Retriever enthusiast who began studying
the disorder in 2005 while at Michigan
State University. Her commitment to
learning more about GRPU is reflected in
her overseeing eye clinics at the annual
Golden Retriever Club of America (GRCA)
National Specialty.
GRPU is often a bilateral disease
affecting both eyes. The distinguishing
sign is radial pigment on the anterior
lens capsule, or the front surface of
the lens of the eye. " Radial pigment
looks like spokes on a wheel where
pigment is deposited in a circular
pattern, " she explains. " A lot of tiny
cataracts may be present on the lens,
though these do not typically threaten
vision. Glaucoma, on the other hand,
is painful and may cause loss of vision.
Fibrinous material builds up behind the
iris where fluid needs to flow, which is
a big risk factor for glaucoma. "
Fluid-filled uveal cysts may develop
from the iris or ciliary body, which make
up the vascular lining of the eye. Dr.
Townsend says about 30 percent of
Golden Retrievers develop uveal cysts,
more than any other breed, though not
all dogs with uveal cysts develop GRPU.
In a study by researchers in Canada, 57
percent of dogs with uveal cysts developed
GRPU. However, the exact role of
cysts in the development and disease
progression of GRPU is not known.
" About 58 percent of Golden Retrievers
with multiple uveal cysts at the first
examination develop pigmentary uveitis
compared with 10 percent of dogs with
solitary cysts and 1 percent of those with
no cysts, " says Dr. Townsend. " Uveal
cysts can be difficult to see without
dilation and special equipment as they
could be tucked behind the iris, the
colored part of the eye. These cysts
start appearing at around ages 4 to 6.
" In the early stages of GRPU, dogs are
not in pain and their eyes look relatively
normal, " Dr. Townsend explains. " Most
owners are not likely to recognize the
eye disease. Some may notice a bit of
redness over the white part of the eye,
though it is inconsistent and potentially
things such as dry eye, irritants and even
corneal ulcers can cause redness. "
The lead investigator of three GRPU
studies funded by the AKC Canine Health
Foundation (CHF) with support from
the Golden Retriever Foundation®,
Dr. Townsend aims to identify affected
dogs earlier to help reduce disease
incidence and potentially lead to
improved treatments to prevent or
delay the progression of the disease.
Dr. Townsend's research grants have
focused on:
* Developing a genetic risk model that
can be used to score an individual
dog's risk for GRPU (CHF Grant No.
02569-MOU, from March 1, 2019, to
Aug. 31, 2022)
* Characterizing the composition and
source of amorphous material within
3
IMAGES COURTESY OF DR. WENDY M. TOWNSEND, PURDUE UNIVERSITY

https://akcchf.org/ https://akcchf.org/ https://goldenretrieverfoundation.org/GRF/ https://onlinelibrary.wiley.com/doi/10.1111/vop.12293 https://onlinelibrary.wiley.com/doi/10.1111/vop.12293 https://onlinelibrary.wiley.com/doi/10.1111/vop.12293 https://www.akcchf.org/research/research-portfolio/2569-MOU.html https://www.akcchf.org/research/research-portfolio/2569-MOU.html

Golden Retriever Update - Summer 2022

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