IgG4-related ophthalmic disease involving extraocular muscles: case series

BACKGROUND: To elucidate the clinical features of strabismus associated with IgG4-related ophthalmic disease (IgG4-ROD). CASE SUMMARY: All of the four patients with IgG4-ROD showed marked enlargement of the extraocular muscles, however, two patients showed orthotropia with full ductions and versions. One patient showed a small angle of exotropia and hypertropia of less than 5 prism diopters. One remaining patient showed orthotropia, full ductions and versions despite marked enlargement of the extraocular muscles, then developed hypertropia up to 35 prism diopters with activation of inflammation, which promptly improved after treatment with oral steroids. CONCLUSIONS: IgG4-ROD usually shows normal ocular motility despite extraocular muscle enlargement, which is the key distinguishing feature from other orbital inflammatory diseases. Active flare-up with increased serum IgG4 levels may produce a large angle of eye deviation, but mostly respond well to steroid treatment.