EyeWorld India March 2018 Issue

by Maxine Lipner EyeWorld Senior Contributing Writer In the corneal transplant cataract zone Considering shifting options F or Fuchs’ patients in need of a transplant and cataract surgery, it can be tricky to determine how to best proceed. To help clarify this, investigators in a recent study published in the Asia-Pacific Journal of Ophthalmology 1 looked at how patients fared when the cataract and transplant procedures were combined or done separately, according to Francis Price, MD , Price Vision Group, Indianapolis. The goal was to review cases and determine what might benefit patients most. This was some- thing that had evolved over time. “Early on, we did the cataract first and then the graft, and everyone thought that was the way it should be,” Dr. Price said, adding that in cases where you remove the cata- ract and then return later to do the transplant, the IOL is more apt to remain in place. “When you go back, the zonule apparatus is firmly scarred down to the capsule that’s shrink- wrapped around the IOL, and eve- rything is more stable,” Dr. Price said. “If you do them at the same time, the natural bag of the cata- ract is a lot larger than the plastic IOL so there is some play there.” Because of this, investigators were concerned that the lens might more easily come up and touch the donor tissue in a combined proce- dure, thereby ruining it. Studying staging With this in mind, investigators decided to look at their cases where the surgery was combined versus separated, with the cataract done first to determine which was safer. “We looked at about 500 cases total and found that there was no dif- ference for the final visual acuity or for the cell count on the graft, which is an indication of how healthy it is,” Dr. Price said. This had clinical implications for the type of procedure that could be best done. “There was no increased risk with doing them at the same time,” he said, adding that for many patients this makes the choice clear. “When you ask patients if they want to have them split between two surgeries or have one surgery, they almost always say, ‘Let’s do it at one time and be done with it,’” Dr. Price said. While most patients are happy with a combined, single surgery, there are some who are not. This is particularly the case for those who tend to be hypercritical and want the best vision possible. Such patients may be intent on being able to see both near and distance without spectacles after the cataract portion of the surgery. However, the combined procedure is not well suited for multifocal or extended depth of focus lenses, Dr. Price said, adding that he will not use such IOLs in this case. “I’ll tell patients that’s not an op- tion because we cannot estimate the correct lens power accurately enough,” he said. “You have to get it within half a diopter; if we’re off three-quarters of a diopter, typi- cally patients are not happy.” The problem is that Fuchs’ dystrophy throws off the IOL power calculation due to edema. “There are some changes on the back of the cornea, but the biggest change is on the front surface, and it’s unpredictable how it changes the K readings or the curvature of the anterior surface,” Dr. Price said. “It depends on how much edema there is and whether the edema is primarily in the center of the cornea, which would make it steeper, or if it’s off center.” If edema is not in the center, inde- pendent of how much edema there is, it can flatten the cornea so that after surgery it gets steeper. Either way, the physician will have trou- ble figuring out exactly where the astigmatism is and what the power of the lens implant should be, Dr. Price explained. Separate procedures for special lenses This means doing the procedures separately to enhance accuracy. Practitioners may do DMEK first, then do the cataract surgery 2–4 months later and be able to im- plant an extended depth of focus lens then, Dr. Price noted. There’s also a choice between DMEK and DSEK. “DMEK is the preferable procedure here. DSEK has gotten better as it has got- ten thinner, but the fastest visual recovery and the clearest vision is with DMEK; we don’t have any stroma attached to it,” he said. “Whenever you leave any stroma, the thinner it gets, the more ac- curate it is, but there is still some unpredictability with the final visual result, and you could have a decrease in the quality of the vi- sion.” This is why DMEK is prefer- able. However, since some physi- cians don’t do DMEK, sometimes they will take their chances with a DSEK. “But you run the risk of having more of a distortion with a DSEK than a DMEK,” Dr. Price said. Dr. Price hopes practitioners come away from the study with the realization that the landscape here is changing. “I think the take-home message is that all of these procedures are evolving, and patients’ expectations are evolving, too,” he said. “When we did full thickness grafts, the expectation was that if you got each eye within 3 D of each other, you were happy.” Now, following surgery, some patients want to have good uncorrected vision at both distance and near. What’s more, these patients talk to each other, especially in this era of social media. “It’s important to set expectations,” Dr. Price said. “Not everyone is the perfect case.” EWAP Reference 1. Price FW Jr., et al. Combined cataract/ DSEK/DMEK: Changing expectations. Asia Pac J Ophthalmol (Phila). 2017;6:388–392. Editors’ note: Dr. Price has no finan- cial interests related to his comments. Contact information Price: fprice@pricevisiongroup.net 26 EWAP CATARACT/IOL March 2018