Epidemiology of ocular myasthenia gravis

This case series was conducted to address the limited data on demographic associations among patients presenting ocular myasthenia gravis (OMG).

Included in the analysis were 433 patients diagnosed with myasthenia gravis who had no signs or symptoms of generalized myasthenia gravis.

Most OMG patients were men (60%) who presented at a mean age of 57 ± 19 years. Women displayed a bimodal distribution, with diagnosis peaking at approximately 30 and 60 years of age. In general, men were older than women at diagnosis by about 5 years, the age difference determined with high confidence to be less than 10 years.

Interestingly, non-Caucasian patients were significantly younger at diagnosis, by between 17.3-23.0 (P<0.001) years, with no additive interaction of gender and race. The bimodal distribution pattern in women, as well as the tendency for a younger age at diagnosis in non-Caucasians have been previously described for cases of generalized myasthenia gravis.

Despite the limitations of retrospective data collection and referral bias, the authors state that the similarity of data among the 5 institutions included in the review suggests the findings are generalizable. However, it is not known whether these differences in distribution affect prognosis, disease course, subsequent conversion to generalized myasthenia gravis or responses to treatment.