Diagnosis of Congenital and Acquired Hyperdeviation: What Are the Rules?

Acquired or congenital hyperdeviation (HD) is caused by dysfunction of one or more vertical rectus or oblique muscles or tendons, (e.g. Graves' ophthalmopathy, orbital myositis) or the nerve supply to these structures. Neural impairment may occur from involvement of nuclear or supranuclear pathways (e.g. nuclear third or fourth nerve palsy, "skew" deviation) or of the peripheral nerve itself (e.g. third or fourth nerve palsy). Myoneural junction involvement (e.g. ocular myasthenia) should be sought in any painless, pupil sparing ophthalmoplegia, especially when variable.