OCT scans use eye as 'window into the brain' for MS prognosis

The connection is common. Eyes are like windows — they can reveal as much about a person as a bay casement can about the room it illuminates. And according to two studies recently released by Johns Hopkins University, that predominantly spiritual image may, now more firmly than ever, actually have a basis in scientific fact.

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Johns Hopkins researchers found that an inexpensive eye scan system has the ability to assess brain inflammation accurately in people with devastating autoimmune disorders, such as multiple sclerosis (MS). The tool, known as optical coherence tomography (OCT), surveys the nerves deep in the rear of the eye, evaluating previously immeasurable layers of light-sensitive retinal tissue. What’s more, an OCT costs one-tenth of an MRI; it also doesn’t apply harmful radiation to the patient being tested.

"Eye scans are not that expensive, are really safe, and are widely used in ophthalmology, and now that we have evidence of their predictive value in MS, we think they are ready for prime time,” Peter A. Calabresi, MD, a professor of neurology at the Johns Hopkins University School of Medicine and leader of the studies, said in a news release. “We should be using this new quantitative tool to learn more about disease progression, including nerve damage and brain atrophy."

For one examination — the results of which were published in the journal Lancet Neurology — Calabresi and his team measured the swelling of the inner layer of the retina in 164 patients with MS; 60 control patients were also involved, and all of the studies’ cohort were given MRIs to measure possible swelling in the brain. If swelling was particularly severe in a given patient’s OCT scan, researchers found that the brain showed a similar increase in inflammation, suggesting a direct relationship between the organs.

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In a second study “Calabresi and colleagues looked at eye and brain scans of 84 MS patients and 24 healthy controls. This time, they focused on two other deep retinal layers, the ganglion cell layer + inner plexiform layer (GCL+IPL), and the peripapillary retinal nerve fiber layer (pRFNL). Greater cell wasting in those areas was strongly correlated with more atrophy in the gray matter of the brain, signifying more nerve damage from MS.”

Collectively, both studies trumpeted the effectiveness of OCTs in relaying valuable information about the brain, through the eye.  

“It’s a way of driving quantitative information about how healthy the nerves are in the back of the eye,” Calabresi said. “And now that it definitively relates to what’s happening in the rest of the brain, we think that certainly every MS clinic should have this and we’re starting to develop some evidence that it may have applications in other neurological diseases like Alzheimer’s disease, maybe Parkinson’s disease.

Calabresi expressed to PhysBizTech that while some of the results were surprising, information such as this was right on point.

“The surprising part was that the patient has much inflammation in their eyes and actually had what we would call macular edema — the swelling in the back of the eye, the retina, that had previously been mostly linked with patients who have diabetes or typically if they were older patients,” he said. “It hadn’t been described in many patients who had multiple sclerosis previously, so that was a surprise. And the extent of the inflammation was a surprise. We were going into this hypothesizing that the eye was going to be a window into the brain, so the fact that it did have a predictive value for the brain parameters of MS was not totally surprising, but of course we were pleased that the results were highly significant.”

The findings suggest that more of neurology become acquainted with OCT scans as a means to further develop prognosis practices in the beginning stages of MS and other similar conditions.

“It’s really not diagnostic; it’s prognostic,” Calabresi added. “You still need other information to diagnosis the disease and the findings that we are looking at are not necessarily specific to MS, they can be seen in other disease. But I do think that they will have a role in assessing patients and determining whether they are at risk for more aggressive forms of the disease.”

Calabresi listed the following as key aspects physicians and specialist should remember about the research:

1. These little micro-cysts that are a form of macular edema can actually occur in young people with MS. If people see or hear that they have macular edema, they should start thinking beyond the eye, thinking that this could be a sign of inflammation in the rest of the brain as well.

2. MS may not be a disease that’s limited to the milinated portions of the nervous system. We think that this may really shift our thinking about MS, guide us toward thinking about MS as an inflammatory disease of the nervous system and not just the milan.

3. This [method] could be used as an outcome measure in clinical trials, reparative therapies.

Find more information about the studies here.

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Comments (1)

Lauren: By writing: "What’s more, an OCT costs one-tenth of an MRI; it also doesn’t apply harmful radiation to the patient being tested.", it could be interpreted that an MRI causes harmful radiation. It does not - it is not a CT scan that relies on radiation, but an electromagnet. Very different.

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