The fornix incision (Video 14-1) is made in either the superior or, more frequently, the inferior quadrant. The incision is located on bulbar conjunctiva, not actually in the fornix, 1–2 mm to the limbal side of the cul-de-sac, so that bleeding is minimized. The incision is made parallel to the fornix and is approximately 8–10 mm in length.
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Bare sclera is exposed by incising the Tenon capsule deep to the conjunctival incision. Using this exposed bare sclera, the surgeon engages the muscle with a succession of muscle hooks. The conjunctival incision is pulled over the hook that has passed under the muscle. All 4 rectus muscles and both oblique muscles can be explored, if necessary, through inferotemporal and superonasal conjunctival incisions.
When properly placed, the 2-plane incision can be self-closing at the end of the operation by gentle massage of the tissues into the fornix, with the edges of the incision splinted by the overlying eyelid. Some surgeons prefer to close the incision with conjunctival sutures.
The fused layer of conjunctiva and Tenon capsule is cleanly severed from the limbus. Some surgeons make the limbal incision (peritomy) 1–2 mm posterior to the limbus to spare limbal stem cells (Video 14-2). A short radial incision is made at each end of the peritomy so that the flap of conjunctiva and Tenon capsule can be retracted to expose the muscle for surgery. At the completion of the operation, the flap is reattached, without tension, close to its original position with a single suture at each corner. If the conjunctiva is restricted from prior surgery or shortened by a long-standing deviation, closure should involve recession of the anterior edge.
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.