Incision and Wound Complications
Proper incision construction and closure are critical in reducing surgical complications. An incision that is too large may result in fluid efflux and intraoperative shallowing of the anterior chamber. An incision that is too tight may restrict fluid influx, increasing the risk of corneal burn. Scleral, limbal, or corneal wound strength is only 10% of normal tissue strength at 1 week, increasing to just 40% by 8 weeks and 75%–80% of its original strength by 2 years. Some studies have suggested that sutureless clear corneal incisions may be responsible for an increased incidence of postoperative wound leakage and subsequent greater risk of endophthalmitis. More studies are needed to determine whether incision location or other confounding factors lead to an observed increased incidence of endophthalmitis.
Table 10-1 High-Risk Characteristics for Intraoperative Challenges and Complications
All incisions should be checked to ensure closure at the end of the surgery. When gentle pressure is applied to the eye and to the edge of the incision with cellulose sponges, the incision should maintain integrity without leakage, and the eye should maintain a physiologic pressure. If the incision leaks, additional stromal hydration can be performed, or the incision can be closed with suture or tissue adhesive.
Prior corneal trauma or existing corneal incisions from laser in situ keratomileusis (LASIK), radial keratotomy (RK), or keratoplasty may become unstable during cataract surgery. It is important to avoid making incisions that interfere with or cross any existing incisions. Any wound dehiscence can be secured with sutures.
Thermal wound burn
Thermal injury to the incision may result in whitening of the corneal tissue, contraction, and wound gape (Fig 10-1). During phacoemulsification, heat may be transferred from the needle to the cornea because of inadequate cooling of the phaco tip. This can result from an insufficient inflow of coaxial irrigation fluid or from occlusion of outflow at the phaco tip or aspiration line by an ophthalmic viscosurgical device (OVD) or lens material. This complication is more common with a dispersive OVD, increased lens density, and use of continuous, rather than intermittent, ultrasound energy. Bimanual small-incision surgery raises the risk, because the phaco needle is in direct contact with the cornea without an irrigating jacket.
Friction produces heat, thereby causing the corneal collagen to contract at a temperature of 60°C or higher, which subsequently distorts the incision. If the distortion is significant, wound gape may occur with associated leakage. Although the overall incidence is low (0.037%–0.10%), the result of a wound burn is significant: these incisions are not usually self-sealing and thus require suturing, a sliding scleral flap, tissue adhesive, or patch grafts for adequate closure. Postoperatively, induced astigmatism is a significant concern.
Figure 10-1 Thermal wound burn. A, Contraction and whitening of anterior corneal tissue (arrow) cause wound gape. B, Multiple sutures are required for closure.
(Courtesy of Uday Devgan, MD.)
Figure 10-2 Descemet membrane detachment. A, Optical coherence tomography (OCT) of the anterior segment. Note the epithelial bullae (arrow) anterior to detachment (arrow head).B, Slit-lamp photograph of corneal edema superiorly (arrow). The detached membrane is reflected inferiorly (arrowhead).
(Part A courtesy of Benjamin Currie, MD; part B courtesy of Thomas L. Steinemann, MD.)
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.