Title: Orbital implantation of biocompatible magnets for the treatment of severe visual impairment due to intractable nystagmus.
Funder: Department of Health and Social Care

Abstract: Visual impairment in the context of nystagmus (abnormal oscillation of the eyes), where correctable, is commonly caused by the instability of the visual image. The management of nystagmus is therefore aimed at reducing the amplitude of the eye oscillation. Neither medical nor surgical approaches have hitherto yielded satisfactory results: the former, because the target neural mechanisms are too complex to manipulate pharmacologically, the latter because surgical immobilisation of the eye adds more symptoms than it removes (Ref 1). The theoretically optimal solution is to damp down the oscillation when the eyes are fixating on an object but to allow free movement during gaze shifts. Such a solution can only be achieved by action-at-a-distance" made possible by the use of a magnetic implant with two components: one fixed to the orbit and another fixed to the eye, the magnetic force between them damping the oscillation in the primary position of gaze while allowing free movement of the eyes. A pilot implantation in one subject has established the potential success of the approach: visual acuity improved from 6/9 bilaterally to 6/6 on the right and 6/5-2 on the left, reflecting an objectively measured change in nystagmus amplitude on the left from 1.11 degrees to 0.13 degrees (Wilcoxon Rank Sum Test, Z=9.33, p In this study we plan to extend this pilot work to a series of patients with intractable nystagmus. This will involve refining the prototype implant design so as to optimise its applicability, performance, ease of application, and economics and quality of manufacture; recruiting a series of patients with intractable nystagmus suitable for implantation (target N=12, acceptable N=6); assessing objectively and subjectively their visual function and quality of life before and after the treatment; and obtaining regulatory approval (CE marking) for use of the device in more extensive clinical trials with an aim to delivering a new standard clinical therapy in the near future. The viability of the approach is supported by health economic analysis that suggests a potential benefit of 1 to 2 Quality Adjusted Life Years per patient, placing the treatment within the justifiable cost threshold defined by NICE guidelines. Its impact on the community is supported by a potential market of ca. 3 million patients in Europe and North America alone, of which we estimate at least 0.1% will be reachable. At the widely quoted figure of 50 000 USD per QALY, this would place the potential monetary value to society of the work in excess of 150 million USD. "

Lay abstract: Nystagmus is where a patient has involuntary roving of the eyes, the treatment for which is generally extremely poor. The roving of the eyes leads to severe visual impairment, as the patient is unable to fixate on an object. In addition, such patients often have the permanent sensation that the world is rotating (true vertigo), which is often associated with a chronic feeling of sea-sickness. Medical treatment for nystagmus is poor and prior surgical therapy often aimed to disconnect the muscles from the eyeballs, leading to a relatively frozen" globe -- also very inconvenient. Implantation of a small magnet onto one of the main muscles that moves the eyeball can be used, however, to damp down the nystagmus when another "anchor" magnet is fixed nearby to the orbital (eye socket) wall. In a single-patient pilot study we have shown, both subjectively and objectively, that the implanted magnets have improved the patients visual functioning by markedly reducing the wobble of the eyeballs. The patient has also expressed delight with the improvement in his quality of life. The major advantage of the magnet damping is that the patient can overcome the magnets by deliberate refixation of the eyes, thereby allowing him or her to look to extremes of gaze in an emergency situation. It is now necessary to roll out the study to a larger group of patients, to check the reproducibility of the pilot study results and to allow refinement of the design of the implantable magnets with a view to production for treating this previously almost untreatable condition."

Research activity codes: 6.3 MEDICAL DEVICES
Health categories: EYE