Intraocular pressure elevation associated with blood in Schlemm's canal after strabismus surgery

PURPOSE: To report a case of increased intraocular pressure (IOP) associated with blood in Schlemm's canal following strabismus surgery. OBSERVATIONS: A 43-year-old female presented with acquired comitant esotropia. The patient had undergone an uneventful bilateral medial rectus recession and right lateral rectus resection operation under general anesthesia. Routine post-operative follow-up at day 3 detected a marked chemosis at the temporal side of the conjunctiva, an elevated IOP of 30 mmHg, and the presence of blood in Schlemm's canal in the temporal angle of the right eye. Episcleral venous outflow impairment was hypothesized to be the cause of secondary ocular hypertension in this patient. IOP was controlled with anti-glaucoma drops. Conjunctival chemosis, IOP, and blood in Schlemm's canal gradually decreased, and all topical medications were ceased at 11 weeks after the surgery. CONCLUSION AND IMPORTANCE: An IOP elevation can be an early complication after strabismus surgery. The presence of blood in Schlemm's canal suggests that the cause is impairment of episcleral venous flow. Although the episode can be transient, this report underlines the importance of IOP examination during the early post-operative period.