EyeWorld Asia-Pacific December 2013 Issue

35 EWAP rEfrActivE December 2013 Refractive surgery for keratoconus by Maxine Lipner EyeWorld Senior Contributing Writer Considering options to normalize vision T here was a time when refractive surgery for keratoconus patients was considered an absolute contraindication. Today, however, refractive techniques from lens exchange with phakic toric implants or toric lenses to the use of intracorneal ring segments are helping keratoconus patients to improve their vision. Even laser refractive surgery, which can be paired with collagen crosslinking or topographic-guided reshaping, is now being touted in some arenas. Historically, prior to surgical intervention, keratoconus patients were managed with toric or rigid gas permeable contact lenses to regularize their irregular astigmatism, according to Jimmy K. Lee, MD, director of refractive surgery, Montefiore Medical Center, University Hospital for Albert Einstein College of Medicine, Bronx, NY, USA. “There was nothing in between contact lens fitting, which is non-surgical, and corneal transplantation for decades,” Dr. Lee said. That changed with the arrival of intracorneal ring segments (Addition Technology, Des Plaines, Ill., USA) about 10 years ago, which Dr. Lee describes as plastic segments embedded into the corneal stroma. “It’s almost like having braces for the cornea, regularized to flatten the steepness of the cone and to regularize the cornea,” he said. With this technology, Dr. Lee noted, patients can have spectacular results, allowing them to get out of their contact lenses, or at least have better vision with their contact lenses. However, he added, one downside here is that predicting who will succeed with intracorneal ring segments isn’t as well defined as with some other surgical techniques. One thing that has changed recently is the technique used to insert these ring segments, a method that Dr. Lee viewed as a bit crude. “The surgeon would have to jam the circular blade through the tunnel, and you couldn’t tell exactly where the depth was,” he said. Now, insertion of the ring segments can be done in tandem with the sophisticated femtosecond laser, he pointed out. “The surgeon can tell the laser exactly the depth and dimensions of the tunnel in the cornea to dictate where you want those segments to be,” he said. “The accuracy of the intracorneal ring segments has been much greater in terms of placement.” This has translated into improved results. There has been a slew of data from five to seven years out that indicates long-term improvement of visual outcomes and in topographic status, Dr. Lee said. Carl Zeiss Meditec AT Torbi in a keratoconic eye with its shape improved by a single Ferrara intracorneal ring Source: Sheraz Daya, MD continued on page 37