Poets say the eyes are a window to the soul.
Perhaps. But to doctors, who communicate in famously earth-bound prose, they’re also a window to underlying disease.
While the uninitiated may observe their friend’s bloodshot eyes and extrapolate they’re recovering from a night of heavy drinking, the eyes – namely the retina – offer doctors a rare, direct view into more serious systemic conditions.
“Diabetes and hypertension highlight how the retina is unique. It’s really the only part of the body where we can see the see blood vessels and visualize the disease,” said Dr. Karyn Bourke of Four Corners Eye Clinic.
On Thursday evening at the Durango Public Library, Bourke told 30 rapt audience members about the toll diabetes and hypertension can exact on the retina.
Diabetes is the leading cause of blindness in patients 20 to 64 years old, and after 20 years of diabetes, 99 percent of people with Type 1 and 60 percent of people with Type 2 experience some degree of retinopathy.
“Blood vessels really tell the story,” she said.
Bourke said the retina “is a very small part of the body. But the list of what it entails is actually far larger than you can imagine.”
During her talk – “Retina: A Discussion of How Systemic Conditions May Exhibit Changes Within the Eye” – Bourke showed a picture of a healthy retina, which looked like a marble that contained thin, elegant, curling threads – blood vessels.
Then she showed a picture of an unhealthy retina where macular ischemia – a common by-product of diabetes – had induced neovascularization, or the abnormal growth of blood vessels.
“See this?” she said. “This lacy network of blood vessels?”
Lacy was one way to put it. In the photograph, it looked like a deranged octopus was growing inside the marble, its arms taking over the retina and sprouting limbs in every direction, such that they were curling into each other.
Then she showed a photo of an eye experiencing a vitreous hemorrhage – where the overgrowing blood vessels bled into the retina.
This time, it looked like the octopus inside the marble had spewed ink everywhere.
Bourke said that if you had “swelling at the very center of the retina,” which often attends diabetic macular edema, she would most likely recommend an injection that works by stimulating leakage of the vessels.
She presented a photograph of the procedure: A pair of disembodied, gloved hands held a syringe with a tiny needle that pierced the eye of a patient – whose eyelids were held open by an “eyelid holder.”
While the photograph managed to capture the miracle of modern medicine with terrific precision, it also proved a little much for some audience members, who shifted in their seats.
“I don’t want to gross anyone out. The needle is really little,” Bourke said. “I’ll move on.”
Bourke said getting on top of lifestyle factors that contribute to diabetes and hypertension – like managing one’s blood sugar and making time for regular exercise – are vital first steps to eye health.
Bourke uses three tests to examine the health of blood vessels in and around the retina.
The first one is the basic dilation test.
“People hate that,” she said. “But it’s a great first step to check for abnormalities, thickening and swelling.”
The second, OCT – or Optimal Coherence Tomography – provides a 3-D image of the retina using a near-infrared light.
“In terms of clarity, this test has gotten so much better in the last 10 years,” she said.
The third, fluorescein angiography, “is what I use when I’m really concerned about those blood vessels,” she said.
This test involves injecting a sodium dye into the arm, to see how long it takes to travel through the bloodstream to the eye.
“Few people enjoy it,” she said, laughing.
cmcallister@durangoherald.com
