ABSTRACT
To compare the sensitivity of edrophonium test and neostigmine test in ocular myasthenia. Materials and methods: the edrophonium and neostimine tests in 57 consecutive patients who presented with symptoms of ptosis and/or binocular diplopia upon exertion were studied prospectively in Neuroophthalmologic Unit, Siriraj Hospital. The palpebral fissure, marginal reflex distance (MRD), levator palpebare superioris muscle function and angle of deviation by Prism and cover test were measured before and after performing the tests for evaluation of positive result of the edrophonium and neostigmine tests. All patients were treated with pyridostigmine for one week. The patients who responded to the treatment were diagnosed as ocular myasthenia gravis. Statistical analysis was carried out by the Chi-square test. Results: Forty-five patients were diagnosed as ocular myasthenia gravis and 12 patients were nonmyasthenic group. The edrophonium test was positive in 44 patients (97.8%) and the neostigmine test was positive in 38 patients (84.4%) in myasthenic group. In nonmyasthenic group, 12 patients (100%) were found negative in both tests. Edrophonium produced more severe side effects than neostigmine. Conclusion: The neostigmine test displayed similar positive result compared with the edrophonium test but is safer and easier to perform.