EyeWorld Asia-Pacific December 2018 Issue

Real-world spin on toric lenses by Maxine Lipner EyeWorld Senior Contributing Writer How these perform in everyday practice T oric lenses have become an important part of the cataract surgeon’s tool box. But how effective are these lenses in the real world? In a study published in BMC Oph- thalmology , investigators took a look at this. Investigators found that while the majority did well, 9% of eyes required further intervention to rectify IOL rotation, according to Kanmin Xue, MB, PhD , clinical lecturer, University of Oxford, U.K. In the unit in which Dr. Xue works, toric lenses are commonly placed in the eyes of patients who have corneal astigmatism of greater than 2.5 D. Investigators wanted to see if it was clinically useful and cost effective to do so, Dr. Xue explained. He felt that his unit was in a prime position to examine this. “There isn’t a lot of data in the general health service setting on toric lenses because a lot of pub- lished results come from special- ists who are experts at putting in toric lenses, and usually it’s one surgeon doing all of the cases,” he said. “This is one of the first studies where there was a real mix of sur- geons of all levels in the hospital.” Included here were 10 consultants and 10 specialists of various grades of training with regard to implant- ing these lenses. Toric investigations Included were 32 eyes of 24 patients who underwent cataract surgery during a 10-month period. Inves- tigators found that approximately 81% of patients obtained an im- provement in best corrected visual acuity after surgery with a toric lens implant, which they may not have achieved with a standard lens implant given their astigmatism. “Also, 80% of eyes ended up within plus or minus 1 D of the predicted refractive outcome, which is quite reasonable,” Dr. Xue said. He thinks this suggests that the majority of In eyes with a toric implant, the majority of patients do well, but in a few cases realignment may be needed. Source: Kanmin Xue, MB, PhD patients experienced a real benefit from the toric implant. However, not all cases went smoothly. Three patients required further surgery to rectify a lens rotation. “Two of those patients had previous retinal detachment repair or vitrectomy, which seems to be a risk factor for lens rota- tion,” Dr. Xue said. One possibility is that there is less gel pushing on the lens, which means that there’s more freedom for the lens to rotate. Or there is zonular weakness that allows for the rotation. “In those patients I would be particularly careful in counseling them about the potential risks before implant- ing a toric lens,” Dr. Xue said. “Also, it’s relevant when you are trying to do a public healthcare type of cost analysis.” For this you have to take into account the potential need for a second surgery, with the associ- ated cost. It’s important to know which candidates may be at risk for lens rotation, such as those who are post-vitrectomy. Dr. Xue said this doesn’t mean they can’t have a toric lens, only that they need to be aware of the heightened risk of rota- tion, which may need to be rectified with a second procedure. Still, the majority of patients with significant astigmatism benefited from a toric lens, and rotations are relatively rare. “The spectacle freedom is an continued on page 56 EWAP CATARACT/IOL 55 December 2018