EyeWorld Asia-Pacific December 2020 Issue

EWAP DECEMBER 2020 23 SECONDARY FEATURE Hiroko Bissen-Miyajima, MD Professor, Dept. of Ophthalmology Tokyo Dental College Suidobashi Hospital 2-9-18 Kanda-Misakicho, Chiyoda-ku, Tokyo, Japan 101-0061 bissen@tdc.ac.jp ASIA-PACIFIC PERSPECTIVES T he occurrence of complications in cataract surgery has been reduced with advancements in technology and our knowledge. Corneal wound burn is one such complication. I have read this article with interest and a somewhat nostalgic feeling. In 1992, I presented “Video-thermography of ocular tissue and handpiece of phacoemulsification” at the 10th ESCRS Congress. Heat was generated at the incision area at close contact with the ultrasound (U/S) tip and the temperature increased over 50˚C, as mentioned in this article. The mechanism of this type of corneal burn was experimentally evaluated with the U/S tips at different positions. 1 The lesson we learned from the video-thermography was the importance of the cooling effect of the irrigating fluid between the U/S tip and silicone sleeve, as Dr. Nijm also recommended in this article. The good news is the introduction of the U/S pulse mode, which has a great potential to reduce the corneal burn compared to the continuous mode, especially in cases with dense cataract. In addition, understanding the characteristics of ophthalmic viscosurgical device being used avoids unnecessary obstructing the irrigating fluid around the U/S tip. The management of corneal burn is usually to suture the incision. In 2020, we have been discussing the selection of toric intraocular lenses to reduce corneal astigmatisms as much as possible. Suturing damaged cornea will result in high amounts of irregular astigmatisms— the opposite of reducing corneal astigmatism. The first priority in cases with corneal burn is sealing the incision to avoid any leakage and postoperative infection; however, the suture may influence visual function. I tell the residents that once the egg is boiled, the egg white will never return to be clear, just like corneal burns. The change in the cornea is not just a cosmetic problem but also a functional problem. We have been discussing cases of corneal would burn for over 30 years. It is time to see technical developments to avoid the extreme temperature increase of the U/S tip and some warning systems, or pharmacological solutions of wounded cornea. Reference 1. Bissen-Miyajima H, et al. Thermal effect of corneal incisions with different phacoemulsification tips. J Cataract Refract Surg. 1999;25:60–64. Editors’ note: Prof. Bissen-Miyajima is a consultant for Alcon and Johnson & Johnson Vision. balance between creating a pocket under the viscoelastic when removing the nucleus and keeping the viscoelastic up against the cornea for endothelial protection, while not restricting fluid movement in the eye. “As soon as I noticed whitening, I stopped, removed the phaco handpiece, and tested it for occlusion. At that point, I ensured an adequate pocket was present to allow fluid egress and carefully removed the remainder of the cataract with as little energy as possible,” Dr. Nijm continued. She said the wound was leaky from the minor burn and required three sutures at the end to close. The patient had 2D of astigmatism postop, which was much less than expected. Dr. Nijm said there is usually more astigmatism to start, and over time (several months), it tends to dissipate. “It was a good lesson for me early on and is something to always be aware of,” Dr. Nijm said. Dr. Nijm offered the following pearls to avoid instances of wound burn: • Understand the importance of fluid movement to allow the egress of fluid and the cornea to cool. There is heat generated at the ultrasound tip, and if there isn’t enough fluid movement, it can cause a burn. • Pre-chop as much as possible when you have a dense nucleus. miLOOP (Carl Zeiss Meditec) can be helpful to accomplish that in cases of mature cataract. • Create a precise incision and look for signs early on (such as a white, smoky appearance in the anterior chamber as you phaco). • Once whitening at the wound occurs, a corneal burn has already taken place. Therefore, it is important if you see any potential signs to immediately stop, remove the phaco tip, check for an occlusion, ensure fluid is properly moving in the eye, and carefully proceed forward. ‘I switched to bimanual phaco for better fluidics’ Dr. Talley Rostov had one case of wound burn in her career, more than a decade ago. “Healon 5 [Johnson & Johnson Vision] had recently come out, and I had heard it was useful for maintaining the chamber in complex cases. I had a patient with a dense cataract and IFIS. I didn’t realize just how well the Healon 5 maintained the chamber and did not allow circulation of fluid. This was also with older phaco technology,” Dr. Talley Rostov explained. The wound burn that resulted from this combination was difficult to close, requiring sutures and glue. The patient had significant astigmatism, even after sutures were removed, Dr. Talley Rostov said. Fortunately, it was correctable with glasses.