Magnetic implants used to treat nystagmus

Post date: 
Wednesday, 28 June 2017
3D image of magnetic prosthetis (credit Dr Parashkev Nachev)

Doctors have successfully used magnets implanted behind a person’s eyes to treat nystagmus, a condition characterised by involuntary eye movements.

Researchers from UCL and University of Oxford have recently published a case study in Ophthalmology describing the first successful use of an implant known as an oculomotor prosthesis. A newly developed set of magnets were implanted in the socket beneath each eye of a patient with nystagmus in order to control eye movement and prevent flickering.

 

Dr Parashkev Nachev, lead author of the paper says, “Our study opens a new field of using magnetic implants to optimise the movement of body parts”.

Nystagmus is a condition which causes constant uncontrolled movement of the eyes. It’s caused by a problem with the way the eye sends messages back to the brain or how parts of the brain which deal with eye movement make sense of the information. 

Researchers around the world are looking at different aspects of nystagmus with the aim of developing treatments and a lot of this work focuses on how the eye movements are controlled.

The patient who underwent the procedure developed nystagmus in his late 40s after treatment for Hodgkin’s lymphoma, which had a great impact on his life and led to him losing his job. His difficulties prompted the research team to investigate the use of an oculomotor prosthesis which had previously only been described theoretically.

The prosthesis they developed involved two interacting magnets, one implanted in the bone at the bottom of the eye socket (the orbital floor) and another in one of the extraocular muscles, which control the eye’s movement.

 

“Fortunately the force used for voluntary eye movements is greater than the force causing the flickering movements, so we only needed quite small magnets, minimising the risk of immobilising the eye,” said Professor Quentin Pankhurst who led the design of the prosthesis.

After the procedure, testing showed the patient’s 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, his symptoms have remained stable. He has managed to return to paid employment and reports substantial improvement in daily activities such as reading and watching television.

The researchers caution that their prosthesis wouldn’t be effective for everyone with nystagmus, as magnetic implants are not suitable for patients who require regular MRI scans. Furthermore, more research needs to be done to understand which patients would benefit the most from future procedures.

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