Most Commonly Injured Muscle in Inferior Blepharoplasty
The inferior rectus muscle is the most commonly injured extraocular muscle during lower eyelid blepharoplasty, though the overall incidence of strabismus after blepharoplasty remains very low at under 3%. 1
Mechanism of Injury
The inferior rectus muscle sustains damage during lower blepharoplasty through several mechanisms:
- Direct surgical trauma from excessive cautery, hemorrhage, and misdirected dissection during the procedure 1
- Scarring and fat adherence in the periorbital tissues that restrict muscle movement 1
- Local hemorrhage without permanent loss of function, which may cause transient symptoms 1
Clinical Presentation and Natural History
When inferior rectus injury occurs, patients typically present with:
- Vertical diplopia that is often incomitant (varies with gaze direction), making prism correction rarely satisfactory long-term 1
- Symptoms that may be transient, with many cases improving after 8 to 15 months if the injury results from local trauma or hemorrhage without significant scarring 1
- Persistent diplopia beyond 6 months that is unlikely to resolve spontaneously and warrants referral to a strabismus specialist 2
Important Clinical Pitfalls
Critical timing consideration: If diplopia has not resolved or demonstrated improvement within 6 months of the blepharoplasty procedure, spontaneous resolution becomes unlikely and surgical intervention should be considered 1, 2
The low overall incidence (under 3% in 920 procedures) should not create false reassurance, as when injury does occur, it significantly impacts quality of life through persistent diplopia and loss of binocular vision 1
Comparison with Other Procedures
For context, the inferior rectus muscle is also the most commonly affected muscle (70% of cases) following retrobulbar or peribulbar anesthesia used in various ocular procedures, demonstrating its anatomical vulnerability in the periocular region 1