Eyeworld

I MANAGING IRREGUR CORNEAS PRIOR TO CATARACT SURGERY N FOCUS 44 | EYEWORLD | NOVEMBER 2019 When Fuchs' patients need cataract surgery, deciding whether to do a combined procedure (if a corneal proce- dure is needed) or staged procedure depends on the patient. And if it's combined, how does the physician determine IOL power? Mark Terry, MD, described a recent case where a patient with Fuchs' put off cataract and transplant surgery. The patient had massive corneal swelling, blistering, and scarring on the surface. The patient's other eye also had Fuchs', though less severe, and its axial length was the same as the other eye. Dr. Terry asked the pa- tient how his vision was 10–20 years prior, find- ing out that the patient could see well without glasses in both eyes. As such, Dr. Terry planned an IOL based on the patient's healthier eye and performed a triple procedure where he removed the scar, performed phaco, and followed with DMEK. "I took the keratometry on the eye that did not have swelling and used that for my calcula- tions on the eye that had terrible swelling, that way I could feel confident that the IOL I put in would have the same outcome as if he didn't have the horrible swelling," Dr. Terry said. But what if the patient hadn't seen well without glasses prior? What if the axial lengths were different? In cases where you can't obtain accurate keratometry in the face of known irregular astigmatism, Drs. Terry, Colby, and Chamberlain said cataract surgery would be staged after DMEK, DSEK, or Descemet's stripping only (DSO), the corneal procedure depending on the patient's situation and the surgeon's capabilities. "We are increasingly doing DMEK surgery first in patients who present with Fuchs' and waiting to do the cataract," Dr. Chamberlain said. "This step normalizes the cornea and cre- ates a more predictive refractive outcome when cataract surgery is done." References 1. Sun SY, et al. Determining subclinical edema in Fuchs' endothelial corneal dystrophy: Revised classification using Scheimpflug tomography for preoperative assessment. Ophthalmology. 2019;126:195– 204. 2. Fan W, et al. Femtosecond laser-assisted cataract surgery in Fuchs' endothelial corneal dystrophy: Long-term outcomes. J Cataract Refract Surg. 2018;44:864–870. 3. Yong WWD, et al. Comparing outcomes of phacoemulsification with femtosecond laser-assisted cataract surgery in patients with Fuchs' endothelial dystrophy. Am J Ophthalmol. 2018;196:173– 180. 4. Zhu DC, et al. Outcomes of conventional phacoemulsification versus femtosecond laser- assisted cataract surgery in eyes with Fuchs' endothelial corneal dystrophy. J Cataract Refract Surg. 2018;44:534–540. The benefit of a combined cataract and corneal procedure is time, expense, and saved endothelial cells. "You always worry about doing phaco [later] with an endothelial keratoplasty graft. Are you going to damage some of those endothelial cells that you transplanted?" Dr. Colby said. If irregular astigmatism cannot be cor- rected or if Fuchs' is not being addressed with endothelial keratoplasty or DSO, Dr. Chamber- lain said he would choose a monofocal lens. Dr. Chamberlain cited analysis of a randomized, controlled patient population of DMEK and DSEK patients that found the cornea flattened or lost power in two-thirds of cases and steep- ened or gained power in the remaining third. "Granted, these shifts are small but can be enough to create greater than 1 D of refrac- tive surprise. For this reason, when combining cases, I typically use monofocal lenses," he said. He also advised making a smaller capsulorhexis in combined cases and noted the importance of a clear enough cornea for safe cataract surgery. "Use aids such as trypan blue, if necessary. Di- late the pupil only with intracameral, preserva- tive-free epinephrine so that it is easy to reduce pupil size later in the surgery when beginning the endothelial keratoplasty." Dr. Terry said he would use a toric lens in some patients. "I use toric lenses in combined cases with DMEK, but I let the patient know it's not quite as accurate. … They may need to have the lens rotated if their astigmatism changes after the swelling is gone," he said. Multifocal IOLs in this subset of patients gave the surgeons pause. "I think there are situations where you could get away with a multifocal, but why?" Dr. Colby said. "If someone has a corneal dis- ease that is significant enough to need corneal continued from page 42 "We are increasingly doing DMEK surgery first in patients who present with Fuchs' and waiting to do the cataract." —Winston Chamberlain, MD

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