Accommodative and vergence findings in ocular myasthenia: A case analysis

Myasthenia gravis (MG) is a neuromuscular disorder that affects skeletal mu scles, in particular, the extraocular muscles. Response variability is a ha llmark sign. Detailed findings are described in a patient with MG in which the presenting sign was accommodative insufficiency. Objective accommodativ e findings were recorded 3 years before the onset of myasthenia, soon after the initial diagnosis was made, and then after the treatment commenced wit h pyridostigmine. In addition, clinical measurements were obtained periodic ally at different times of the day for various binocular motor functions, i ncluding near point of convergence, phoria, fusional and accommodative ampl itudes, and relative accommodation. The disease adversely affected all acco mmodative and vergence findings, with fatigue being the primary disturbance . The therapeutic administration of pyridostigmine improved static measurem ents of accommodation and vergence and reduced asthenopia. The objective dy namic measurements of accommodation, vergence, and versions were less affec ted. These findings provide a clear demonstration that both intrinsic and e xtrinsic ocular muscles may be affected in the prepresbyopic myasthenic pat ient.