Limbal relaxing incisions are making a comeback in an era of high expectations for cataract surgery outcomes and increasingly sophisticated IOLs. The procedure for performing this type of incision is relatively simple and can be performed by experienced surgeons at the slit lamp in the office.
Rockville Centre, NY-Use of limbal relaxing incisions (LRIs) is a vital surgical technique that is gaining increased importance in the world of cataract surgery, where even small amounts of cylinder cannot be tolerated.
"[LRIs] allow the surgeon to reduce astigmatism and dramatically improve patients' postoperative results," said Eric D. Donnenfeld, MD, FACS, co-director, cornea, Nassau University Medical Center, East Meadow, NY, and founding partner, Ophthalmic Consultants of Long Island, Rockville Centre, NY.
"With new technology for IOLs, including aspheric, multifocal accommodating, and toric lenses, patients have higher expectations and greater visual demands following cataract surgery," Dr. Donnenfeld said. "One of the simplest and most effective ways to improve patient outcomes following surgery is to do [LRI].
LRIs, diamond-knife incisions into the peripheral cornea, are very useful in correcting small-to-moderate amounts of residual astigmatism. The procedure has been used for decades but is having resurgence due to the increased demands of patients having cataract surgery.
"In the past, LRIs had only been adopted by a small minority of cataract surgeons. We are now seeing a significant increase in LRIs, and many ophthalmologists are adopting this technology," Dr. Donnenfeld said. "LRIs are not quite as accurate as excimer laser photoablations for correcting residual cylinder. However, because of their ease of use and the ability to do them at very little expense and to adjust treatments, the cost-effectiveness of this procedure makes it a very viable alternative."
Approximately 40% of the patients in his practice undergoing cataract surgery have an LRI performed either intraoperatively or postoperatively, he said.
Although the nomograms for LRIs were fairly complex in the past, there is no reason to make the procedure overly complicated, Dr. Donnenfeld said, adding that he has developed a nomogram for those incisions. It is based on the concept of treatment with one incision for 0.5 D, making the incision 1.5 clock hours in length. For 0.75 D, he uses two paired incisions of one clock hour on the steep axis; 1.5 D, two paired incisions and two clock hours; and for 3 D, two incisions and three clock hours.
"While you can achieve larger results with longer incisions, I have found that [LRIs] of more than two clock hours are associated with irregular astigmatism and glare and halo, and for this reason I will very commonly debulk the astigmatism to reduce it by 1.5 D by using two incisions," Dr. Donnenfeld said. "If there is any residual cylinder left, I can always go back and do excimer laser photoablation at another time."
Although the technique for performing LRIs is fairly simple, it has a slight learning curve. Dr. Donnenfeld recommended that ophthalmologists who are not experienced at performing LRIs begin by doing procedures on patients undergoing conventional cataract surgery in the operating room, and who are under peribulbar anesthesia. After becoming more comfortable with the procedure, surgeons can perform the procedure with patients under topical anesthesia, with advanced technology IOLs, and at the slit lamp in the office postoperatively.
Performing an LRI at the slit lamp takes about 30 seconds and can resolve small amounts of cylinder fairly effortlessly without taking the patient back to the operating room, he explained. For in-office procedures, Dr. Donnenfeld said he uses topical perocaine followed by lidocaine gel and makes the incision with a preset 0.6-mm diamond knife with a small angulation at the periphery. This design is easy to use at the slit lamp, he said. Postoperatively, he prescribes a topical corticosteroid and fourth-generation fluoroquinolone.
Dr. Donnenfeld said he typically performs the LRI at the beginning of cataract surgery because he prefers to work on a firm, well-hydrated eye, and the cornea tends to become thinner as it dehydrates under the operating microscope. He determines where to place the incisions by looking at a printout of the patient's preoperative corneal topography, which is turned upside down because he is operating from the patient's head.