Retrobulbar hemorrhages vary in intensity and are more common with retrobulbar anesthetic injections than with peribulbar injections, with an incidence of 0.44%–0.74% following retrobulbar injection.
Venous retrobulbar hemorrhages are usually self-limited and tend to spread slowly. Arterial retrobulbar hemorrhages occur more rapidly and are associated with taut orbital swelling, marked proptosis, elevated IOP, reduced mobility of the globe, inability to separate the eyelids, and massive ecchymosis of the eyelids and conjunctiva. This type of retrobulbar hemorrhage causes an increase in orbital volume and associated orbital pressure, which can restrict the vascular supply to the globe. Large orbital vessels may be occluded. Tamponade of the smaller vessels in the optic nerve may occur, resulting in severe vision loss from anterior ischemic optic neuropathy and subsequent optic atrophy, despite the absence of obvious retinal vascular occlusion.
Ophthalmologists can often make the diagnosis of retrobulbar hemorrhage by observing the rapid onset of eyelid and conjunctival ecchymosis and tightening of the orbit. The diagnosis can be confirmed by tonometry revealing elevated IOP. Ophthalmoscopy may reveal pulsation or occlusion of the central retinal artery in severe cases.
Treatment of acute retrobulbar hemorrhage consists of maneuvers to lower the intraocular and orbital pressure as quickly as possible, such as the following:
intravenous osmotic agents
lateral canthotomy and cantholysis
localized conjunctival peritomy (to allow egress of blood)
The planned surgery should be postponed until the IOP and mobility of the globe and eyelids are normal. To reduce the risk of a recurrent retrobulbar hemorrhage, it may be advisable to use another form of anesthesia for the second attempt at surgery.
In addition to retrobulbar hemorrhage, potential complications of retrobulbar injections include central retinal artery occlusion, ischemic optic neuropathy, toxic neuropathy or myopathy, diplopia, ptosis, and inadvertent subdural injections with possible central nervous system depression and apnea. Ischemic complications are more common if epinephrine is used in the anesthetic. (See BCSC Section 1, Update on General Medicine, and Section 6, Pediatric Ophthalmology and Strabismus.)
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.