Alleviation of myogenic ptosis by magnetic force.

Abstract

Ptosis has usually been treated by surgery and the literature contains suggestions of over eighty different operations for its correction. Duke-Elder (I952) has pointed out that, in spite of the variety and ingenuity of remedial operations, the results are by no means invariably brilliant and in cases due to neuromuscular disease shortening of the lid is usually unsatisfactory. Apart from the cosmetic defect, treatment is necessary for visual reasons when the ptosed lid covers the pupil and obstructs vision. Walshe ( I957) stated that the ptosis of myasthenia gravis should usually not be operated upon. For the ptosis of ocular myopathy, operation may be contraindicated because of the problem of exposure keratitis in the absence of Bell's phenomenon. At the Endocrine Unit, New End Hospital, there is a register of 340 cases of myasthenia gravis. Some of these patients have been referred to the Eye Clinic because of ptosis, which is the commonest and often the presenting symptom. These patients have in the past usually been treated by the provision of crutch glasses, which are useful when operation is contraindicated or not accepted by the patient, where the difficulty is temporary, or in the case of an elderly patient. Lid crutches to elevate the eyelid were introduced by Goldzieher (i890), who used a shell plate attached to the upper rim of a shell spectacle frame. Since then other appliances have been described, such as an adjustable watch spring (Kauffman, I893); an independent wire crutch (Meyer, I893); flexible single wire (Dodge, I 935); and a scleral contact lens with a superior ridge. Patients using crutch glasses often experience discomfort with the forced opening of the eye and watering owing to the pressure of the wire loop on the upper lid. All electro-motive force used in commerce is magnetic in origin and it was thought that a magnetic force might be a useful method for elevation of the ptosed eyelid, especially in myasthenia gravis with its variable nature, remissions, and exacerbations. Ptosis may be alleviated by inserting a metallic magnetic implant into the upper eyelid and elevating the eyelid by the action of a small magnet unobtrusively placed behind the upper rim ofa spectacle frame. The attracting force pulls the eyelid upwards and forwards. Alternatively a metal strip may be fixed on to the upper lid using a skin adhesive. If it is placed in the upper palpebral furrow, the metal strip will be hidden in the skin crease of the furrow when the lid is elevated. There is no pressure on the eyelid as with a crutch spectacle, and the weight of the lid is taken off the eye. The power of the orbicularis muscle can overcome the magnetic force so enabling the patient to blink.