Magnets have been used for the first time to treat a condition nystagmus.
A study, led by University College London (UCL) and University of Oxford, UK, describes how researchers implanted a newly developed set of magnets in the socket beneath each eye of one patient with the condition.
The procedure, published in the latest edition of Ophthalmology, is the first description of a successful use of an implant, called an oculomotor prosthesis, to control eye movement.
And lead study author Dr Parashkev Nachev, from UCL’s Institute of Neurology, said the breakthrough opens a new field of using magnetic implants to optimise the movement of body parts.
“Nystagmus has numerous causes with different origins in the central nervous system, which poses a challenge for developing a pharmaceutical treatment, so we chose to focus on the eye muscles themselves,” said Dr Nachev.
“But until now, mechanical approaches have been elusive because of the need to stop the involuntary eye movements without preventing the natural, intentional movements of shifting gaze.”
The patient who underwent the procedure developed nystagmus after suffering from Hodgkin’s lymphoma and as a result, experienced a number of difficulties, including losing his job.
This led the researchers to investigate the effectiveness of an oculomotor prosthesis, which had previously been described theoretically, but not confirmed in practice.
The research team, led by Professor Quentin Pankhurst, from UCL’s Medical Physics & Biomedical Engineering department, developed a prosthesis, which comprised one titanium-encased magnet implanted on the orbital floor that interacted with a smaller magnet sutured to one of the extraocular muscles.
The magnetic prostheses were implanted in two separate sessions, one for each eye, and testing showed that his overall visual acuity was substantially improved, and there has been no negative impact on his functional range of movement.
Over four years of follow-up reports, the patient’s symptoms have remained stable and he has returned to paid employment and reports substantial improvement in daily activities such as reading and watching television.
Professor Christopher Kennard, of the University of Oxford, who co-led the study, said: “While the exact neural mechanisms causing nystagmus are still not fully understood, we have shown that it can still be corrected with a prosthesis, without needing to address the neural cause. What matters here is the movement of the eye, not how it is generated.”
The researchers added that the magnets are not suitable for patients who require regular MRI scans and that more research should be carried out to establish which patients would benefit most from the procedure.
Nachev P, Rose G, Verity D et al. Magnetic Oculomotor Prosthetics for Acquired Nystagmus. Ophthalmology 26 June 2017; doi: 10.1016/j.ophtha.2017.05.028
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