November 2019

GLAUCOMA

YES Connect
A close look at the glaucoma suspect


by Liz Hillman EyeWorld Editorial Co-Director

Glaucoma suspect is one of the most common conditions we see as ophthalmologists, and I thought I knew everything there was to know about it until I heard what Drs. Richter and Sheybani had to say about this stubbornly inconclusive condition. In this month’s column our specialists share their tips and tricks for getting reliable baseline studies, new diagnostic techniques, and when to be suspicious of something besides glaucoma. For both our YES members and ophthalmologists who have been in practice for years, reexamining how we manage these patients can help to streamline their care and yield a more accurate final diagnosis. I will start adding more OCT studies to my workup­—read on, and see what changes you might be making to your practice!
—Julie Schallhorn, MD
YES Connect Co-Editor

With glaucoma, once the damage is done, it’s irreversible, which is why identifying—and following—glaucoma suspects before they even have an optic nerve defect is vital to protecting their vision. What is considered suspect? How often should these patients be assessed?
Arsham Sheybani, MD, and Grace Richter, MD, shared their thoughts on how to navigate identification and monitoring of glaucoma suspects.
“Unfortunately, there is no hard science on who is a true glaucoma suspect, and we can never know which of these patients will actually develop glaucoma in the future,” Dr. Richter said in an email to EyeWorld.
Red flags on an exam that put a patient in glaucoma suspect category, according to Dr. Richter, include: an enlarged cup-disc ratio (CDR), CDR asymmetry, focal thinning of the neuroretinal rim, disc hemorrhage, or retinal nerve fiber layer defect. Elevated IOP and a glaucomatous visual field are other factors that would lead Dr. Richter to monitor a patient over time for the progressive condition. Factors such as a family history of glaucoma, thin central corneal thickness, myopia, older age, and African or Latino ancestry are associated with an increased risk for glaucoma and should be taken into consideration with exam findings as well, Dr. Richter said.
The most important thing to do with glaucoma suspects, Dr. Sheybani said, is serial follow-ups. First, you can catch something that you just missed the first time, he said. And, second, they allow you to assess whether it’s a person who might progress rapidly or not.
“Sometimes you’ll do a field every 6–9 months for a couple of years. You get 3–4 visual fields as baselines, and if things are steady and there is no change, then you feel a little better about it,” he said, adding that, generally, yearly follow-ups of glaucoma suspects are handled by referring doctors or optometrists in his practice.
In addition to establishing a baseline with a series of visual field tests and monitoring that over time, Dr. Sheybani sees a value in using OCT.
“Sometimes there is variability between scans and sometimes it’s kind of burdensome, but if you’re really trying to do it right, you want to get a couple of scans at the start, the first visit. Then follow those scans over time with some sort progression analysis, if you have it,” he said.

Here’s a breakdown of the studies Dr. Richter performs the first time she sees a glaucoma suspect:
• Gonioscopy to determine whether the angle is open
• Visual field testing to assess any defects that could suggest actual glaucoma and to set a baseline in case there is other pathology present
• Stereoscopic examination of the optic nerve to identify focal defects of the neuroretinal rim and retinal nerve fiber layer defects
• Disc photos to capture a baseline of the optic nerve that can be followed over time with truly longitudinal comparisons
• OCT to assess retinal nerve fiber layer thickness to identify focal glaucomatous defects and establish a baseline
• OCT angiography of the peripapillary retinal nerve fiber layer microvasculature to identify early focal glaucomatous defects that other tests might not detect and establish a baseline

Dr. Richter noted that patients should be allowed to practice and learn how to take visual field tests, due to the learning curve that’s often involved.
After these tests, depending on the patient’s level of risk, Dr. Richter said she sees patients 6 months to a year after the initial visit and then every 1–2 years. During these visits, she’ll look for evidence of progressive thinning of their OCT retinal nerve fiber layer thickness in any focal regions around the optic nerve, development of visual field defects, development of focal peripapillary glaucomatous defects on OCT angiography, and evidence of increased thinning of the neuroretinal rim.
She also pointed out that half of patients with open angle glaucoma have a baseline IOP in the normal range. As such, “it’s important not to develop a false sense of security that a patient doesn’t have glaucoma when their eye pressure is ‘good.’”
Dr. Sheybani said if the optic nerve looks glaucomatous, but there is no pressure elevation and no angle closure, a primary optic nerve process, such as a compressive lesion or optic tract pathway lesion in the brain, vascular changes or ischemic optic neuropathies that could lead to cupping, should be ruled out through history and careful examination.
“If your suspicion is high enough for something compressive, then you do need to do a scan,” Dr. Sheybani said.
When it comes to talking with a patient who needs to be followed as a glaucoma suspect, the important thing is to not scare them.
“You want to let them know that they may not notice the symptoms, which is why it’s so important to keep the follow-up,” Dr. Sheybani said. “If you tell them, ‘Look, we don’t think this is glaucoma, but we’re worried that this could progress to glaucoma, which is why we are following you a little closer. It’s important to make the follow-up because sometimes we’ll be able to detect it before you can notice it. If it happens, we can’t reverse the damage, so our whole goal is prevention. Make sure you keep the visits and the good news will be if it stays normal.’”

About the doctors

Grace Richter, MD
Assistant professor of clinical ophthalmology
Glaucoma Service
University of Southern California, Roski Eye Institute
Los Angeles

Arsham Sheybani, MD
Assistant professor of ophthalmology and visual sciences
Washington University
School of Medicine
St. Louis

Relevant financial interests

Richter: Carl Zeiss Meditec
Sheybani: Allergan, Katena, Glaukos, Ivantis

Contact information

Richter: Grace.Richter@med.usc.edu
Sheybani: sheybaniar@wustl.edu

A close look at the glaucoma suspect A close look at the glaucoma suspect
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