So goes the flow—but not always

The arterial blood supply to the anterior segment of the eye comes primarily from the ophthalmic artery and is carried to the eye by the anterior ciliary arteries and the long posterior ciliary arteries. The usual seven anterior ciliary arteries follow a course along the four rectus muscles; however, the two long posterior ciliary arteries take an intrascleral course and are located deep to the medial and lateral rectus muscles. The anterior ciliary arteries and long posterior ciliary arteries contribute to several collateral circulatory systems including the episcleral limbal plexus, the intramuscular circulation within the ciliary body, and the major arterial circle of the iris root.1-3 Because of this extensive collateral supplying the anterior segment, ischaemia following strabismus surgery or manipulation of the ciliary arteries is relatively rare.

Anterior segment ischaemia was first documented in experimental animals after ocular surgery.45 Investigators described irregular dilated pupils and iritis after rectus muscle surgery in primates. The first clinical reports of anterior segment ischaemia resulting from ocular surgery date back approximately 50 years.6 Anterior segment ischaemia has now been reported to be associated with retinal …