Background: Ocular myasthenia gravis (OMG) is the most common focal form of myasthenia gravis (MG) characterized by variable weakness and fatigability of extraocular muscles (EOMs), levator, and orbicularis oculi. Most of the OMG patients will subsequently progress to develop more disabling and life threatening generalized myasthenia gravis (GMG). No definitive laboratory tests are available for the diagnosis of OMG. Hence, we aimed at characterizing the clinical profile of ocular myasthenia gravis in Indian population. Methods: We evaluated 30 suspected cases of ocular myasthenia referred from various parts of country (India) under the Department of Neurology, NIMHANS, Bangalore from October 2010 to October 2013. Detailed demographic and clinical data was extracted in a systematic manner using a predetermined proforma. All patients were investigated with neostigmine test, icepack test, Repetitive Nerve Stimulation (RNS), serum acetylcholine receptor (AChR) antibody assay and Single Fiber Electromyography (SFEMG). Results: Twenty of 30 patients were recruited. Among these twenty patients, 18 patients fulfilled SFEMG criteria (SFEMG ADHOC committee criteria, 1994) and remaining 2 patients (who were not willing for SFEMG) had clinical features of OMG and showed positive results in other tests.Among those, 17 (85%) were male and 3 (15%) were female. Ptosis was the most common symptom and was seen in 19 (95%) patients. Diplopia, the second commonest symptom was seen in 12 (60%). Eighty five percent (85%) ptosis and 75% of diplopia had shown diurnal variation. Shifting ptosis was observed in 20%. Conclusion: Systematic elicitation of clinical signs and symptoms has very important role in the diagnosis of OMG. Variable and fatigable ptosis and diplopia with diurnal variations are the diagnostic symptoms of OMG. Shifting ptosis and Coganýÿs lid twitch sign are the very important signs of OMG.

Keywords: Eextraocular Muscles; Ptosis; Fatigable Weakness; Acetylcholine Receptor; Neostigmine.