Clinical and imaging features of congenital and acquired isolated inferior rectus muscle hypofunction.

Abstract

BACKGROUND:

Inferior rectus (IR) underaction may arise from various causes that are distinguishable through imaging. We investigated clinical and imaging characteristics of congenital and acquired causes of IR underaction.

METHODS:

Cases of IR underaction were selected from data prospectively collected in a study of orbital imaging in strabismic patients.

RESULTS:

Review identified 3 cases of congenital IR underaction (2 with bilateral IR aplasia and 1 with unilateral IR hypoplasia), 12 acquired cases, including 4 due to denervation (2 idiopathic, 1 after multiple strabismus surgeries, 1 after head trauma), and 8 cases of direct IR damage (5 with orbital trauma and 3 with previous surgery, including 2 sinus surgery and 1 laser blepharoplasty). Of the 23 cases, 11 adults had high-resolution magnetic resonance imaging, and 2 children had computed tomography. Imaging identified the anatomic diagnosis in congenital cases; in acquired cases, imaging helped to identify atrophy and exclude alternative orbital causes; and in direct mechanical damage, imaging clarified the mechanism of underaction, extent of IR damaged, and the degree of retained contractility. Patients with congenital IR absence or hypoplasia exhibited A pattern exotropia that was typically absent in isolated acquired denervation or direct IR damage.

CONCLUSIONS:

Orbital imaging demonstrates a variety of abnormalities in patients with congenital or acquired IR hypofunction, helping to clarify the underlying mechanism and guide management.

• Authors: Federica Solanes, Joseph L Demer
• Journal: Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus (J AAPOS) Vol. 25 Issue 1 Pg. 11.e1-11.e9 (02 2021) ISSN: 1528-3933 [Electronic] United States
• PMID: 33601045 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Topics

• Adult
• Child
• Humans
• Magnetic Resonance Imaging
• Oculomotor Muscles (diagnostic imaging, surgery)
• Ophthalmoplegia
• Strabismus (diagnostic imaging, etiology, surgery)
• Tomography, X-Ray Computed