Myastheniagravisisadiseaseinwhichantibodiesdirectedatnicotinicacetylcholinereceptorsareproduced,leadingtoadeficiencyofacetylcholinereceptorsattheneuromuscularjunction.Thisresultsinimpairmentofmuscularexcitation,whichappearsclinicallyasfatigablemuscleweakness.Weaknessoftheextraocularmusclesoccursinnearly90%ofallmyasthenicsatdiseaseonset,（1）withptosisbeingthemostcommonpresentingfeature.Myastheniagravisaffectingoneoracombinationoftheextraocularmuscleswithoutptosisislesscommon;however,casessuchasbilateralinternuclearophthalmoplegiawithoutptosishavebeendescribedintheliterature.TheauthorspresentacaseinwhichdecompensatingesophoriawasthepresentingfeatureofMG.
重症肌无力是一种产生针对烟碱型乙酰胆碱受体抗体的疾病，导致神经肌肉接头处乙酰胆碱受体的缺乏。结果导致了肌肉活动功能受损，临床上表现为肌肉疲乏无力。90%的重症肌无力发作时可以出现眼外肌无力，（1）睑下垂是最常见的症状。重症肌无力影响一条或一组眼外肌而没有眼睑下垂的情况比较少见，然而文献中有报道双侧核间性眼肌麻痹不伴有睑下垂的病例。作者提供了一个以不可逆性内隐斜视为表现的重症肌无力病例。
