ONLINE EXCLUSIVE
Cataract
September 2023
by Ellen Stodola
Editorial Co-Director
Phaco wound burn (also known as corneal incision contracture) occurs when the heat generated by the phaco probe—both through mechanical energy and friction—results in thermal damage to surrounding corneal tissue, said Zeba A. Syed, MD. The phaco needle is covered with a silicone sleeve, and irrigation fluid typically bathes the phaco needle and cools the tip. Fortunately, this complication of cataract surgery is extremely rare with an incidence of less than 0.1%.1,2
Lisa Park, MD, also stressed that phaco wound burn is a very rare complication, with the reason for this being the evolution of safer phacoemulsification equipment. This has improved tremendously, she said. “If it does happen, it’s something that has to be recognized quickly and dealt with quickly because the results can be very difficult to manage,” she said. Dr. Park said that phaco wound burn may have been slightly more common about a decade ago, but newer machine iterations have helped to cut down on the problem.
“Surgeons should be intentional about ‘floating’ and pivoting the phaco needle in the corneal incision instead of pushing it against the walls of the incision. This latter maneuver forces the needle against the silicone sleeve and corneal tissue and blocks irrigating fluid that would cool it off.”
Zeba A. Syed, MD
Dr. Park said that the phacoemulsification tip generates heat, but it has a protective sleeve and irrigating fluid that bathes the eye, allowing the tip to be cooler, protecting the cornea. “As long as you have that working correctly, that is the best protection,” she said. “The times where we used to see phaco wound burn were cases where there was a high degree of phacoemulsification over a long period of time or when people were putting the handpiece into the eye; if they didn’t recognize that the irrigation was working [incorrectly], that could predispose phaco wound burn.” She also said risk factors include when the wound is very tight or dense viscoelastic is blocking the tip and has not been cleared.
Dr. Syed said that the primary risk factor for phaco wound burn is the degree of ultrasound energy used during cataract surgery. Higher levels or longer phaco time (as is the case with dense nuclear cataracts) is associated with an increased risk.
While this is a complication that occurs very infrequently, Dr. Syed said surgical techniques that rely more on ultrasound energy instead of mechanical forces (e.g., chopping) are associated with a higher risk.
To help reduce the risk, she said careful inspection of the silicone sleeve before inserting the phaco needle into the corneal incision is critical. An improperly fitted sleeve may disrupt fluid flow and result in thermal damage at the corneal wound.
“Surgeons should be intentional about ‘floating’ and pivoting the phaco needle in the corneal incision instead of pushing it against the walls of the incision,” she said. “This latter maneuver forces the needle against the silicone sleeve and corneal tissue and blocks irrigating fluid that would cool it off. Also, surgeons should be aware of signs of blockage of the phaco needle, as [this] may occur with viscoelastic material.” Dr. Syed said that one clue indicating occlusion is a whitening region of emulsified lens at the phaco tip. Blocked fluid flow results in a local buildup of thermal energy and higher risk of wound burn.
Dr. Syed said to look out for whitening of the corneal stroma and gaping at the incision, as these are signs of phaco wound burn. The surgeon may note the incision leaking more during the remaining steps of surgery with resulting chamber instability. “I typically recommend suturing the incision and abandoning it for another, fresh incision,” she said. “Suturing of a burned incision is complicated by its irregular internal surfaces and may require multiple sutures to seal.”
Dr. Syed said that a horizontal mattress suture often works well by tethering the roof of the incision to the floor across its entire length. Patients should be counseled that they will likely have higher levels of postoperative astigmatism from scarring of this incision, she said.
Dr. Park added that one of the main issues is that wound burn can occur very quickly, and the key indication is whitening at the wound. She also said that the problem at this point is closing that wound.
“Normally when we make a wound in the cornea, most of us are doing clear corneal incisions and we don’t put any sutures and that closes easily on its own, but with a phaco wound burn, that’s going to be a gaping wound now, so one has to put a lot of sutures in it,” Dr. Park said. “We usually modify our suture technique, so instead of putting single throws of sutures through the wound, one might have to do a mattress suture or S-shaped suture in order to close that wound.” Because you have to pull tight to close this wound, that can cause long-term difficulty in healing, predisposes to infection, and can cause a lot of astigmatism, Dr. Park said.
About the physicians
Lisa Park, MD
Columbia University
New York, New York
Zeba A. Syed, MD
Director, Cornea Fellowship Program
Wills Eye Hospital
Philadelphia, Pennsylvania
References
- Bradley MJ, Olson RJ. A survey about phacoemulsification incision thermal contraction incidence and causal relationships. Am J Ophthalmol. 2006;141:222–224.
- Sorensen T, et al. Ultrasound-induced corneal incision contracture survey in the United States and Canada. J Cataract Refract Surg. 2012;38:227–233.
Relevant disclosures
Park: None
Syed: None
Contact
Park: drlisapark@gmail.com
Syed: zsyed@willseye.org
