Introduction: Ocular myasthenia gravis (OMG) is a most common focal presentation of myasthenia gravis (MG). Most of the recent studies on myasthenia gravis including both generalized and ocular myasthenia used Edrophonium in the diagnosis. As per our knowledge after reviewing available literatures, no study mentioned about the Neostigmine test in a systematic manner. Neostigmine has some advantages over Edrophonium. Present study focused on Neostigmine test in a systematic manner in the diagnosis of OMG Methods: Twenty seven patients of suspected ocular myasthenia underwent clinical examination, electrophysiological (RNS and SFEMG) tests, ice pack test and neostigmine test in a systematic manner. After recording baseline data, 0.6mg of atropine was given intramuscularly and 15min later 0.03mg/kg of neostigmine was given intramuscularly. Subjective and objective improvement in clinical parameters was assessed at 15 minute intervals after Neostigmine injection for up to 1.5 hours. Results: Of 27 patients, 20 were diagnosed to have ocular myasthenia gravis based on clinical criteria and electrophysiological tests. Out 20 OMG patients, 11 (55%) had shown unequivocally positive results and equivocal result seen in 6 (30%) of patients. 2 patients with restricted extraocular movements without baseline diplopia developed diplopia at 3044 minutes of the test. All seven non myasthenia patients had shown negative results. It has 85% sensitivity, 100% specificity with 100% positive predictive value and 70% negative predictive value. Conclusion: The lower dose (0.03mg/kg) of neostigmine appears to be associated with fewer side effects compared to earlier literature mentioned dose (0.04mg/kg) with equal sensitivity. Improvement in ptosis was more frequent than diplopia. The time interval for maximal improvement in different clinical features varies in a given patient. Therefore, it is necessary to observe the patient for up to 60 minutes during Neostigmine test.

Keywords: Diplopia; Ptosis; Ocular; Neostigmine.