Ocular myasthenia

Abstract

Ocular myasthenia is a special form of general myasthenia gravis characterized by unilateral or bilateral ptosis and eye muscle pareses of distinct variability, depending on the time of day and the state of fatigue of the patient. Most important for diagnosis is the Tensilon test, which can, however, produce negative results. In such cases a combination of the Tensilon test with electromyography is indispensable. In ocular myasthenia there is not always an increase in the antibody titer against acetylcholine receptors in the blood. The treatment of ocular myasthenia is based on the application of cholinesterase inhibitors. The drug of choice is Mestinon; however, the reaction of the eye muscles to this drug is often unsatisfactory. Local application of cholinesterase inhibitors in the form of Eserine, Prostigmin etc. is an additional important therapy. Also in ocular myasthenia the modern treatment with Cortisone (alternate-day therapy with 100 mg Prednisone every second day) has proved very useful. Another possible method of interfering with the immunological systems of myasthenia is immunosuppression with Azathioprin or Cyclophosphamide. The pathognomonic significance of the thymus in the autoimmune process of myasthenia gravis is demonstrated by the good results obtained by thymectomy, which can also be performed successfully in ocular myasthenia, not only in young patients in whom the condition is severe, but also in older patients in whom it is chronic. Often, the therapeutic measures mentioned have to be tested one after another or in combination in order to achieve an optimal therapeutic effect.