versão impressa ISSN 0004-2749versão On-line ISSN 1678-2925
Arq. Bras. Oftalmol. vol.61 no.3 São Paulo jun. 1998
The basic concepts about the introduction of new forces to the oculomotor system, by the use of magnetic fields are presented. This method has two specific advantages: 1) The forces act without any material contact between the element which generates them (a permanent magnet in a periorbital location) and the point of their application (e.g., a ferromagnetic plate fixed to the scleral surface). 2) The forces are not constant (though permanently acting) but depend on the distances between the elements of the magnetic circuit. This allows the generation of forces sufficient to perform an expected function (e.g., the blockade of a nystagmus) without preventing that other greater forces may act. Therefore the stabilization so produced may be overcome and a normal rotation results. With alloys of neodimium, iron and boron, very efficient permanent magnets are obtained. Although of reduced size, they generate the forces required for such oculomotor stabilization. If assembled in metalic plates, their performances are further improved. Besides, there are no practical effects of the magnetic fields beyond the plates fixed to the sclera. Thus, this method is indicated for the treatment of nystagmus but may be also used for other applications as, for instance, that of the adjustement and stabilization of ocular positions, immediately -after surgical correction of strabismus.
Keywords: Nystagmus; Magnets; Adjustments