EyeWorld Asia-Pacific June 2018 issue

June 2018 EWAP FEATURE 29 toric lens, Dr. Greenwood said a surgeon has the option to pair the toric with relaxing incisions to give it a little extra boost. “A lot of surgeons like to use relaxing inci- sions up to 1.5 D,” he said. “You can also do LASIK after placing the toric.” For example, if the patient has more than 4 D, you could place the lens and do refractive surgery to correct the residual refractive error, Dr. Greenwood said, adding that for someone with a long eye, the surgeon may want to do refrac- tive surgery or piggyback on top of the toric. There aren’t any other IOLs available to correct higher corneal astigmatism, Dr. Woodard said. “If I have a patient who has more astigmatism than those lenses will correct, I’ll either use arcu- ate incisions from a femtosecond laser to treat the astigmatism that’s residual or do LASIK/PRK postop- eratively,” he said. “Most commonly in the U.S., the way that I would handle that would be with a bioptics ap- proach,” Dr. Swan said. Toric IOL vs. corneal procedure to correct cylinder “My approach to this is a little dif- ferent because I have ORA [Alcon] to help guide me with how much astigmatism someone has,” Dr. Woodard said. For anyone who has approximately 0.5 D of astig- matism against-the-rule or 0.6 with-the-rule, he will plan to treat astigmatism in some form. Treat- ment could be with a toric IOL or arcuate incisions with the laser. Dr. Woodard said he plans based on input from several technologies: corneal topography, refraction, and the ORA. Dr. Swan said that the typical rule of thumb is if you have greater than 0.74 D against-the-rule or greater than 1.25 with-the-rule, it’s best to go with a toric. “I also use intraoperative aberrometry to see if it makes more sense to do a toric or limbal relaxing incision,” he said. Generally speaking, if it’s greater than those values, Dr. Swan is likely to place a toric and less than that, he will use an LRI. Dr. Holland said there is some debate on the efficacy and stabil- ity of astigmatic treatments. The femtosecond arcuate incisions are more accurate and more stable than a diamond knife LRI, but they’re not as stable as a toric lens, he said. “You can’t predict the tissue response to surgery in each patient’s cornea, so you can get undercorrections or overcorrec- tions; that is why toric IOLs have better outcomes when treating any astigmatism that is not minimal,” Dr. Holland said. Even with femtosecond arcuate incisions, the toric is more ac- curate, Dr. Holland said, and he suggested considering femto arcu- ate incisions for mild astigmatism especially if it is with the rule. When not to implant a toric IOL Dr. Woodard said a patient who has very irregular corneal astigma- tism is not a great candidate for a toric IOL. He added that patients who have corneal disease that causes irregular astigmatism are also not good candidates generally. He said to proceed with caution in these patients, like those with post-cor- neal transplants, those with epithe- lial basement membrane dystrophy (EBMD), or those with Salzmann’s nodular degeneration. “The biggest thing is to make sure the astigmatism is regular,” Dr. Greenwood said. If the patient has irregular astigmatism from anterior basement membrane dys- trophy or something similar, he or she wouldn’t be a good candidate for a toric lens, he said. Similarly, patients with severe keratoconus, where the astigmatism is not regu- lar, wouldn’t be good candidates. Dr. Holland recommends making sure there is no corneal disease that could be accounting for astigmatism such as Salzmann’s nodular degeneration, epithelial basement membrane degeneration, or pterygium. These conditions are unstable and may need to be man- aged and will result in a change of astigmatism. Another situation that Dr. Holland cautions about when using a toric IOL is if the patient has some instability of the capsular bag, the lens could rotate. It might not be advised if there is posterior capsular tear and the capsule is unstable. Monovision with a toric IOL Many monovision patients are being treated with toric contact lenses for monovision, Dr. Wood- ard said, adding that he doesn’t make any special concessions for monovision. He did note that for patients doing monovision in one eye, the near eye is usually more tolerant to residual astigmatism than the distance eye. “In the distance eye, I’d want to correct anyone with at least 0.5 to 0.75 D of astigmatism, but for near, that amount is not usually visually significant,” he said. The way to approach mono- vision with a toric IOL is similar Trulign IOL Source: Bausch + Lomb continued on page 30