Sagging eye syndrome causes acquired adult strabismus

This study found that sagging eye syndrome (SES) represents a mechanical cause of acquired, adult horizontal and vertical strabismus. Because SES is typically associated with clinically obvious adnexal changes, recognition of SES as the cause of chronic or acute acquired diplopia could help avert neurologic evaluation and imaging in most cases.

The authors used magnetic resonance imaging to evaluate rectus extraocular muscles (EOMs), pulleys, and the lateral rectus (LR)–superior rectus (SR) band ligament in 56 orbits of 28 patients diagnosed with SES. They had a mean age of 69.4 years. Data also were obtained from 25 orbits of 14 control participants age-matched to SES and from 52 orbits of 28 younger controls with a mean age of 23 years.

They found that patients with SES commonly exhibited blepharoptosis and superior sulcus defect. Significant inferolateral LR pulley displacement was confirmed in SES, but the spectrum of abnormalities was extended to peripheral displacement of all other rectus pulleys and lateral displacement of the inferior rectus pulley, with elongation of rectus EOMs (P < 0.001).

Symmetrical LR sag was associated with divergence paralysis esotropia and asymmetrical LR sag greater than 1 mm with cyclovertical strabismus. The LR-SR band was ruptured in 91 percent of patients with SES.

The authors conclude that widespread rectus pulley displacement and EOM elongation, associated with LR-SR band rupture, causes acquired vertical and horizontal strabismus. Small-angle esotropia or hypertropia may result from common involutional changes in EOMs and orbital connective tissues that may be suspected from features evident on external examination.