What are pearls for performing lateral canthotomy and cantholysis?

Updated: Jun 11, 2020
  • Author: Anna G Gushchin, MD; Chief Editor: Edsel B Ing, MD, MPH, FRCSC, PhD, MA  more...
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Orbital compartment syndrome is an ocular emergency that requires early recognition and treatment to prevent blindness.

Some key points to keep in mind include the following:

  • Treatment should not be delayed to obtain imaging.
  • The essential component that relieves the orbital pressure is the cantholysis, not the canthotomy.
  • Maintain firm retraction on the lower lid; if procedure is adequate, the lower lid should elevate completely off the globe.
  • When cutting the canthal ligament, aim inferoposteriorly toward the lateral rim [15] to avoid injury to the levator muscle, lacrimal gland, and lacrimal artery, which are located superiorly. [12]
  • The eyelid wound may bleed profusely, but there is very little drainage from the retrobulbar hematoma itself. [16]
  • The surgeon will feel the lower lid pop upward after successful inferior cantholysis, and the lower lid will be completely mobile with inferior cantholysis. [12, 17]
  • Tonometry and globe palpation are contraindicated in patients with an open globe injury.
  • A successful procedure is marked by improved visual acuity, resolution of a previously detected afferent pupillary defect, and decrease in IOP to below 40 mm Hg. [18] Note that proptosis and extraocular motion testing are less reliable indicators of procedure success. [19]
  • If inferior cantholysis does not decrease the orbital pressure, complete release of the inferior canthal tendon should be confirmed before proceeding to superior cantholysis. If the latter does not decrease the intraocular pressure, orbital decompression should be considered.

Whenever feasible, seek emergent consultation with an ophthalmologist when this procedure is performed.

The relative afferent pupillary defect, or Marcus Gunn pupil, is tested using the swinging flashlight test. The result is positive when the affected pupil appears to dilate in response to light (the other normal pupil also dilates when light is shone in the affected eye). Both pupils constrict when the light is shone in the normal eye. The Marcus Gunn pupil results from injury to the afferent fibers of cranial nerve II of the defective eye, while the efferent signals from cranial nerve III of the normal eye are uninjured.

For more information, see the Medscape Reference article Neuro-Ophthalmic Examination.

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