LAUSR

The pulley is the functional origin of the extraocular muscles and prevents their dislocation from the muscle cone. The pulley degenerates with age and may progress to cause the sagging eye syndrome (SES). Divergence paralysis, a type of distance esotropia, occurs when the lateral rectus muscle pulley and lateral rectus–superior rectus (LR–SR) band show degenerated symmetry OU. Cyclovertical strabismus of a small angle occurs when the lateral rectus muscle pulley and LR–SR band show degenerated asymmetry OU. Patients with SES have distinctive features, such as baggy eyelids, deep superior sulcus deformity, and aponeurotic ptosis. SES is the leading cause of non-paralytic diplopia, and its rate increases with age, with 60% of the patients being women. One-third of the cases of SES are distance esotropia of 9Δ on average, and two-third of the cases are small-angle hypertropia of 4Δ on average. Diplopia is cured with surgery, and each case needs to be differentiated from the heavy eye syndrome for diagnosis and treatment.