What decides the nature of extraocular muscle injury? The probable mechanism of flap tear and rupture

Management of traumatic incomplete lacerating rectus muscle injuries using multimodal imaging approach (ASOCT and CT/MRI)

Purpose: To describe the pathophysiology, importance of multimodal imaging approach, and the clinical outcomes of incomplete lacerating rectus muscle injuries. Methods: A retrospective review was conducted to identify patients with ocular deviation secondary to rectus muscle injuries. Between 2019 and 2022, a total of 30 patients were identified, amongst whom eleven patients had incompletely lacerated rectus muscles (secondary to penetrating adnexal trauma and sino-orbital surgeries). Patients' demography, nature of injury, computed tomography/magnetic resonance imaging, anterior segment optical coherence tomography features, intra-operative findings, and post-operative outcomes were reviewed. Results: The mean age of 11 patients was 31.36 ± 14.38 years. All patients had external trauma which severed the muscle in its anterior portion. Five patients had isolated inferior rectus muscle injury (45.45%), three had inferior and medial rectus muscle injuries together (27.27%), two had isolated lateral rectus muscle injury (18.18%), and one remaining patient had isolated medial rectus muscle injury (9.05%). In ten patients (90.90%) CT/MRI revealed features suggestive of muscle injury, however details with respect to muscle insertion and scleral course were lacking. In this difficult scenario, ASOCT filled these lacunae in nearly 90% of the patients by providing surgically useful details. Moreover, when CT/MRI-ASOCT imaging features were combined, the management and outcomes were even more predictable. Conclusions: Penetrating rectus muscle injuries can be better identified as incompletely lacerated muscle using multimodal imaging approach. This simple image correlation process customizes the treatment approach and hence the clinical outcomes.

Aetiology, clinical features and surgical outcomes of isolated medial rectus palsy

IMPORTANCE

Isolated medial rectus palsy is extremely rare in clinical practice.

BACKGROUND

To report demographics, aetiology, clinical findings, imaging features and surgical outcomes in patients with isolated medial rectus palsy.

DESIGN

Retrospective study.

PARTICIPANTS

All patients treated for isolated medial rectus palsy at Zhongshan Ophthalmic Center, Sun Yat-sen University, between September 2003 and March 2019.

METHODS

Review of patient records.

MAIN OUTCOME MEASURES

Aetiology, clinical findings, imaging features and surgical outcomes.

RESULTS

A total of 32 patients (22 males, 10 females) were included. Mean age was 33.19 ± 19.78 years. The right eye was involved in 17 patients, the left eye was involved in 14 patients, and both eyes were involved in one patient. The most common causes were iatrogenic injury (43.75%), followed by trauma (37.50%) and congenital (18.75%). The most common clinical findings included outward deviation, diplopia and limited adduction. Six patients showed combined small-angle vertical strabismus, and 10 patients experienced a scale of -1 motility defect in other directions. After individualized strabismus surgery, preoperative exotropia of 60 ± 25 prism diopters (PD) was significantly reduced to 12 ± 13 PD (t = 10.938, P < .0001). Ocular motility improved in 21 patients, and five patients achieved normal ocular motility. Successful correction was obtained in 20/32 (62.50%) patients, with under-correction in 12/32 (37.50%) patients. Twenty-eight patients had only one surgery, three patients had two surgeries and one patient had three surgeries.

CONCLUSIONS AND RELEVANCE

The most common cause of isolated medial rectus palsy was local injury. Satisfactory results were obtained after individualized surgical interventions based on personalized preoperative evaluations.

Post traumatic retinal injuries: Does the ocular protective reflex play a crucial role?

Traumatic retinal injuries are commonly encountered in most retinal subspecialty clinics. Retinal dialysis, detachment and other complications consequent to blunt trauma are often thought to be due to equatorial expansion of the globe following an antero-posterior compressive force. However, stretching of the globe along the primary anatomical equator may not hold true for the adjusted globe position as a consequence of the protective Bell's phenomenon which gets activated before impact. The upward and outward rolling of the globe likely creates a new equator, with the compressive forces acting along this new plane, thereby leading to stretching along the ocular coats closer to the retinal periphery. Additionally, the coup and countercoup mechanisms with increased vulnerability of temporal sclera predisposes to retinal complications more commonly along the temporal and the nasal retina. Further, retinal complications involving other quadrants can also be explained through understanding of the Bell's phenomenon.