Sagging eye syndrome: connective tissue involution as a cause of horizontal and vertical strabismus in older patients

Abstract

Importance: Recognition of sagging eye syndrome (SES) as the cause of chronic or acute acquired diplopia may avert neurologic evaluation and imaging in most cases.

Objectives: To determine whether SES results from inferior shift of lateral rectus (LR) extraocular muscle (EOM) pulleys and to investigate anatomic correlates of strabismus in SES.

Design and setting: We used magnetic resonance imaging to evaluate rectus EOMs, pulleys, and the LR-superior rectus (SR) band ligament at an eye institute.

Participants: Patients with acquired diplopia suspected of having SES. We studied 56 orbits of 11 men and 17 women (mean [SD] age of 69.4 [11.9] years) clinically diagnosed with SES. Data were obtained from 25 orbits of 14 control participants age-matched to SES and from 52 orbits of 28 younger controls (23 [4.6] years).

Main outcome measures: Rectus pulley locations compared with age-matched norms and lengths of the LR-SR band ligament and rectus EOMs. Data were correlated with facial features, binocular alignment, and fundus torsion.

Results: 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 < .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% of patients with SES.

Conclusions and relevance: 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.

Figure 1

Sagging eye syndrome. A, Deep superior sulcus and left hypotropia distance esotropia. There is marked bilateral limitation of supraduction. B, Left ptosis, left hypotropia, and marked limitation of supraduction in the right eye. C, Left aponeurotic ptosis and deep superior sulcus are more prominent in the left eye, and there is left hypotropia.

Figure 2

Fast spin-echo T2-weighted sequence quasi-coronal plane magnetic resonance imaging. Left, Younger control participant showing lateral rectus (LR)–superior rectus (SR) band. Note the normal morphology of LR muscle with respect to a horizontal reference line drawn through the globe center. Middle, Elderly control participant demonstrated marked elongation of LR-SR band associated with LR muscle sag. Right, Rupture of LR-SR band in sagging eye syndrome (SES) with resultant LR sag. IR indicates inferior rectus; MR, medial rectus; and SO, superior oblique.

Figure 3

Fast spin-echo T2-weighted sequence axial magnetic resonance imaging. Left, Control participant illustrates medial rectus (MR) and lateral rectus (LR) configuration. Right, Marked elongation and thinning of LR more than in sagging eye syndrome (SES). IOL indicates intraocular lens; and ON, optic nerve.

Figure 4

Fast spin-echo T2-weighted sequence quasi-sagittal magnetic resonance imaging. Left column, Morphology and length of the superior rectus (SR) and inferior rectus (IR) muscles in a young control participant. The insertion of the levator palpebrae superioris (LPS) to the tarsus and normal eyelid anatomy is visible. Top right, Aponeurotic ptosis and bowing of the IR muscle in sagging eye syndrome (SES). The LPS is minimally attached to the tarsus. The optic nerve (ON) is convoluted. Bottom right, Another case of SES showing levator disinsertion, ptosis, and marked superior sulcus defect. The SR and IR are markedly elongated and bowed. IO indicates inferior oblique.

Figure 5

Linear regression showing significant correlation between binocular difference in horizontal rectus sag (combined lateral rectus and medial rectus sag) and magnitude of the hypotropia in cyclovertical strabismus.