BLOG: New biomarkers for tick-borne disease identified
Lyme disease is the most recognized term for tick-borne illness, but the tiny bacterial spirochete that causes Lyme, Borrelia burgdorferi, is but one of many possible co-infections carried by ticks.
If not treated, these infections can cause a range of persistent systemic and neurological effects. Of greatest interest to the readers of this blog, tick-borne disease can compromise the brain’s spatial-visual process, resulting in problems with convergence and accommodation, balance and spatial orientation problems, or feeling overwhelmed by movements in the peripheral vision.
Unfortunately, Lyme and other tick-borne infections are notoriously difficult to diagnose, in part because they are great mimickers of other conditions. In addition, standard blood tests miss about 40% of tick-borne infections. It can take more than 2 weeks for the body to establish antigens to the spirochetes. To avoid the body’s attack by the immune system, the spirochetes can burrow into tissues to “hide.” This can result in false negatives when antibody testing is conducted since the spirochete leaves no antigen tracer for the immune system to respond to. There are specialty laboratories for tick-borne infection such as IGeneX and Galaxy Diagnostics. Accuracy may require testing to be repeated more than once.
Early detection is difficult. However, the good news is that we have recently discovered two new biomarkers for tick-borne infection that could facilitate faster diagnosis. In research supported by the Lyme Disease Association (LDA), my colleagues and I have demonstrated that the presence of a hazy, white ring of peri-papillary ischemia around the optic nerve — especially in children or adults younger than 60 years who would not be expected to have ischemic changes — is associated with tick-borne infection. One way that spirochetes hide from the immune system is by building up protective biofilms. We believe that these biofilms clog the narrow capillary vessels just around the perimeter of the optic nerve, blocking blood flow. Clinicians who see these areas of peri-papillary ischemia on fundus evaluation in patients who also have convergence insufficiency or focusing problems (especially for those who present sudden onset of symptoms) should rule out the possibility of tick-borne infection.
The Visual Evoked Potential (VEP) test presents another diagnostic screening opportunity. In a healthy vision system, the first major negative peak occurs around 75 ms (N-75), or 75 ms after the pattern onset. The first major positive peak occurs around 100 ms (P100), and the second major negative peak around 135 ms (N-135). We have found that a sharp drop in amplitude (up to –30 uv or greater) at N-75 is correlated with active tick-borne infection.
Resolution of Lyme-related visual problems often requires prisms to rebalance the visual process, along with antibacterial treatment of the tick-borne infection. Merely treating the infection will not fully address symptoms once the visual process is compromised. With prism lenses that affect the compromised spatial visual processing dysfunction, patients often experience rapid, dramatic improvements that are quite gratifying. Keep in mind that Lyme disease patients have typically seen several other doctors, and many have dealt with debilitating symptoms for years before being tested appropriately and accurately diagnosed. Awareness of the new biomarkers will help speed that process for early detection by the optometrist and ophthalmologist.
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William V. Padula, OD, SFNAP, FAAO, FNORA, is in private practice at the Padula Institute of Vision Rehabilitation in Guilford, Conn. He is the cofounder of the Neuro-Optometric Rehabilitation Association (NORA) and was the founding chairman of the Low Vision Section for the American Optometric Association. He has served as a consultant to the Committee on Vision for the National Academy of Sciences. In addition to being a recognized expert on visual consequences of tick-borne disease, Padula lectures and consults internationally on processing dysfunction caused by a neurological event such as concussion, TBI, stroke, Parkinson’s disease and developmental learning difficulties, to name several visual problems related to stroke and traumatic brain injury.
Visit the Lyme Disease Association and the International Lyme and Associated Diseases Society. To learn more about Lyme disease and vision, see NORA’s brochure on this topic.
Disclaimer: The views and opinions expressed in this blog are those of the authors and do not necessarily reflect the official policy or position of the Neuro Optometric Rehabilitation Association unless otherwise noted. This blog is for informational purposes only and is not a substitute for the professional medical advice of a physician. NORA does not recommend or endorse any specific tests, physicians, products or procedures. For more on our website and online content, click here.