Magnetic resonance imaging in dissociated strabismus complex demonstrates generalized hypertrophy of rectus extraocular muscles

Abstract

Background Dissociated strabismus complex (DSC) is an enigmatic form of strabismus that includes dissociated vertical deviation (DVD) and dissociated horizontal deviation (DHD). We employed magnetic resonance imaging (MRI) to evaluate the extraocular muscles in DSC. Methods We studied 5 patients with DSC and mean age of 25 years (range, 12–42 years), and 15 age-matched, orthotropic control subjects. All patients had DVD; 4 also had DHD. We employed high-resolution, surface coil MRI with thin, 2 mm slices and central target fixation. Volumes of the rectus and superior oblique muscles in the region 12 mm posterior to 4 mm anterior to the globe–optic nerve junction were measured in quasi-coronal planes in central gaze. Results Patients with DSC had no structural abnormalities of rectus muscles or rectus pulleys or the superior oblique muscle but exhibited modest, statistically significant increased volume of all rectus muscles ranging from 20% for medial rectus to 9% for lateral rectus (P < 0.05). Conclusions DSC includes various combinations of sursumduction, excycloduction, and abduction not conforming to Hering’s law. We have found modest generalized enlargement of all rectus muscles. DSC is associated with generalized rectus extraocular muscle hypertrophy in the absence of other orbital abnormalities.

Involvement of dysregulated coding and long non‑coding RNAs in the pathogenesis of strabismus

“…Even different causes, including genetic, nerve regulated and structural modification, were reported to be associated with the development of strabismus ( 19 – 21 ), the EOM dysregulation was regarded as the most direct effector organ among various causes. Through scientific and systematic mRNA detection, the results would provide abundant knowledge on the incidence of strabismus.…”

Diffusion tensor imaging of horizontal extraocular muscles in patients with concomitant and paralytic esotropia

“…Due to the high sensitivity for soft tissue and ability to provide a variety of detection sequences, magnetic resonance imaging (MRI) is the preferred method to study EOM under physiological conditions [7] . At present, MRI studies involving EOM have been focussed at the morphological level, including cross-sectional areas, volume and morphological changes of EOM at different eye positions [8][9] . By contrast, few studies have been performed at the tissue level of EOM function.…”