Retinal ischaemia with cotton-wool spots

US researchers have discovered that peripapillary ischaemia around the optic nerve — especially in children or adults under 60 — is associated with tick-borne infections, including Lyme disease.

Writing in Healio, Dr William Padula, from the Padula Institute of Vision Rehabilitation in Connecticut, said that diseases caused by spirochetes such as Borrelia burgdorferi, the tick-borne obligate parasite which leads to Lyme disease, are difficult to diagnose since they sequester themselves in tissues, often resulting in false negatives from antibody testing.

Further, since it can take more than two weeks from infection for the body to establish those antibodies, standard blood tests miss about 40% of tick-borne infections, he said. Dr Padula and his colleagues have also demonstrated that spirochetes can hide from the immune system by building up protective biofilms. “We believe that these biofilms clog the narrow capillary vessels just around the perimeter of the optic nerve.”

Clinicians who see these areas of peripapillary ischaemia in patients who also have convergence insufficiency or focusing problems, especially those who present with sudden onset of symptoms, should check for tick-borne infection, he said. He suggested the Visual Evoked Potential test as a diagnostic alternative, where a sharp drop in amplitude (-30µv or greater) correlates with active tick-borne infection.