October 2018

CATARACT

Research highlight
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by Maxine Lipner EyeWorld Senior Contributing Writer


A reverse side cut incision is more stable and may offer better access to the subincisional cortex, according to Dr. Donnenfeld
Source: Eric Donnenfeld, MD

Effect of cataract incision choice on wound integrity

The type of cataract incision a practitioner makes can significantly impact wound leakage, according to Eric Donnenfeld, MD, Ophthalmic Consultants of Long Island, New York. Dr. Donnenfeld and colleagues compared the wound integrity of two different femtosecond incisions and a clear corneal manual one in a study published in the Journal of Cataract & Refractive Surgery.1
While many are aware of the advantage in making better capsulotomies and doing astigmatic incisions, investigators wanted to look at the efficacy of a primary incision created with a femtosecond laser. For Dr. Donnenfeld, using a different type of incision was an outgrowth of other surgical experience. “When I started doing reverse side cuts in LASIK, I learned that the incisions were more reliable and the flaps were more stable,” Dr. Donnenfeld said. “What I was wondering was whether we could apply the same idea to cataract surgery.”

Comparing incision types

Included in this prospective case series were 45 eyes of 45 patients who were randomly placed in one of three treatment groups. The 15 eyes in Group A underwent a 110-degree femtosecond reverse side cut clear corneal incision. “We started out by cutting back to the limbus then forward, creating a trap door type incision that we hoped would be better self-sealing,” Dr. Donnenfeld said. A 70-degree femtosecond forward side cut clear corneal incision was created in the 15 patients in Group B. The remaining 15 eyes underwent manual clear corneal incisions, Dr. Donnenfeld reported.
The anterior chamber was irrigated with balanced salt solution to create pressure on the wound. Investigators found that for those in Group A leakage occurred at a significantly higher 28.20 mm Hg of pressure with the reverse side cut clear corneal incision than with the standard side cut incision in Group B, which required just 15.07 mm Hg, or the manual clear corneal incision in Group C, where leakage occurred at 9.93 mm Hg.
There was no leakage found for any of the eyes in Group A at the 1-day postoperative mark. Wound leakage was seen in 53% of eyes in Group B and 87% of those in Group C, Dr. Donnenfeld noted.
“We saw that the reverse side cut incisions had better wound integrity, healed with less leakage, and created a more stable wound,” Dr. Donnenfeld said. He attributes this to the fact that the reverse side cut creates a tongue and groove type of trap door incision, which has larger apposition to the cornea. The reverse side cut also cuts back to the limbus, which investigators think is a significant advantage in creating wound integrity. The intraocular pressure assists in closing this type of wound as well, Dr. Donnenfeld said.
While the regular side cut with the femto laser was better than a manual approach, the difference was not found to be significant.

Practical implications

Dr. Donnenfeld found the reverse side cut wound to be more stable. Because of this he has been able to reduce the length of the incisions. “A shorter incision creates less oar locking and allows us to do better cortical cleanup,” Dr. Donnenfeld said. “Also, it gives us better access to the subincisional cortex, which you don’t have with traditional incisions because they need to be longer to prevent leaking.”
When using a reverse side cut incision, Dr. Donnenfeld stressed the importance of avoiding limbal blood vessels. “These will affect the ability of the femtosecond laser to penetrate into the cornea and may make it difficult to open these incisions,” he said.
Dr. Donnenfeld hopes practitioners come away from the study with the realization that femto laser reverse side cut primary incisions are more efficacious than manual incisions for cataract surgery.
Dr. Donnenfeld thinks the next step is to evaluate the refractive stability of these incisions. This is something that has not been done yet, he said.

Reference

1. Donnenfeld E, et al. Randomized prospective evaluation of the wound integrity of primary clear corneal incisions made with a femtosecond laser versus a manual keratome. J Cataract Refract Surg. 2018;44:329–335.

Editors’ note: Dr. Donnenfeld has financial interests with Alcon (Fort Worth, Texas), Bausch + Lomb (Bridgewater, New Jersey), and Johnson & Johnson Vision (Santa Ana, California).

Contact information

Donnenfeld
: ericdonnenfeld@gmail.com

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