Mechanism of ophthalmic artery occlusion following pars plana vitrectomy

Saito et al present a patient with Terson‘s syndrome and dense vitreous haemorrhage who underwent pars plana vitrectomy and was noted postoperatively to have developed an ophthalmic artery occlusion.¹ They propose that the ophthalmic artery was occluded by the spontaneous release of an embolus from an atheromatous plaque in the internal carotid artery. This seems unlikely in a 39 year old man without a previous history of symptomatic atherosclerotic disease. Although the authors identified plaques in the patient‘s carotid artery by ultrasound, these can be seen in 11% of asymptomatic males under age 40 and may therefore be an incidental finding in this case.²

An alternate explanation for the patient‘s ocular findings is trauma from the retrobulbar injection. Intravascular injection into the ophthalmic artery has been reported as a complication of retrobulbar anaesthesia.³ It is possible that either an intravascular injection or simply needle tip trauma resulted in thrombus formation with obstruction of flow in the ophthalmic artery. It should also be noted that although acute ophthalmic artery occlusion is the presumed diagnosis, the same findings could result from simultaneous obstructions of the retinal and choroidal circulations⁴, also a potential consequence of errant retrobulbar injection. The possibility that the patient‘s chorioretinal disturbance could have been iatrogenic highlights the importance of a thorough preoperative discussion with patients about the risks and benefits of different methods of delivering anaesthesia for ophthalmic surgery.