Anterior Segment Ischemia
The blood supply to the anterior segment of the eye is provided, in part, by the anterior ciliary arteries that travel with the 4 rectus muscles. Simultaneous surgery on 3 rectus muscles, or even 2 rectus muscles in patients with poor blood circulation, may therefore lead to anterior segment ischemia (ASI). The earliest signs of this complication are cells and flare in the anterior chamber. More severe cases are characterized by corneal epithelial edema, folds in the Descemet membrane, and an irregular pupil (Fig 14-8). This complication may lead to anterior segment necrosis and phthisis bulbi. No universally agreed-upon treatment exists for ASI. Because the signs of ASI are similar to those of uveitis, most ophthalmologists treat with topical, subconjunctival, or systemic corticosteroids, although there is no firm evidence supporting this approach.
Figure 14-7 Corneal delle (arrow) subsequent to postoperative subconjunctival hemorrhage.
It is possible to recess, resect, or transpose a rectus muscle while sparing its anterior ciliary vessels. Though difficult and time consuming, this technique may be indicated in high-risk cases. Staging surgery, with an interval of several months between procedures, may also be helpful. Because the anterior segment is partially supplied by the conjunctival circulation through the limbal arcades, using fornix instead of limbal incisions may provide some protection against the development of ASI.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.