Eyeworld

I N FOCUS 38 | EYEWORLD | AUGUST 2019 CATARACT SURGERY POST-LVC Contact information Clinch: tclinch@edow.com Kugler: lkugler@kuglervision.com Waltz: kwaltz56@gmail.com Williamson: blakewilliamson@weceye.com by Liz Hillman EyeWorld Senior Staff Writer these patients, as well as the optical zone size and the epithelial map. In addition to taking at least two topog- raphy measurements and comparing with the results obtained by optical biometry, Dr. Clinch said there is another important preoperative assessment. "I evaluate how well the patient perceived their day and night vision after LASIK. When patients describe excellent visual quality, I am more confident that they will adapt to the visual disturbances of diffractive IOLs," he said . Dr. Clinch said that during the counseling process, he explains to patients that he actually doesn't operate on their vision. Cataract surgery changes the optics of their eye. "Vision is how the brain interprets the sensory input, and ev- eryone's brain is slightly differently," he said. Higher order aberrations Most post-refractive patients are post-myopic LASIK, Dr. Waltz said, making spherical aberra- tion relatively common. These patients, he not- ed, are used to the halo and ghosting caused by this aberration. Dr. Waltz said cataract surgery, at a minimum, can decrease the total amount of positive spherical aberration and minimal amounts can still be tolerated postop. It can also be treated with topography-guided PRK or LASIK or with aspheric IOLs, Dr. Kugler said. People who have had prior hyperopic LASIK tend to have negative spherical aberration. "What is important is to measure the spher- ical aberration of the cornea so that you can get the net result of where the patient started and what you did to it," Dr. Waltz added. Things can get tricky with coma, which can occur if the ablation or incisions are decentered from the visual axis. "If you have asymmetric higher order ab- errations, like coma, they are very difficult to fix and need to be taken care of in terms of preop and postop discussions," Dr. Waltz said. Dr. Waltz emphasized that fixing sphere and cylinder are primary goals, followed by improving higher order aberrations. Y ou've got a patient in your chair. It's time for preop diagnostic testing and a cataract surgery consult. This patient's history shows prior refrac- tive surgery. "You need to start with the understanding that this patient has a different set of expectations and you're chal- lenged because of the prior refractive surgery. It's more difficult to hit your refractive target— and there is more pain involved if you don't," said Kevin Waltz, MD. There are special considerations at each stage—preop testing, patient expectations, IOL calculations and IOL selection, and postop enhancements—for prior refractive surgery patients seeking cataract surgery. Dr. Waltz, Lance Kugler, MD, Blake Williamson, MD, and Thomas Clinch, MD, shared how physicians can set themselves up for success at the preop stage. Preoperative diagnostics While most of the physicians said their preop testing is the same for every patient regardless of prior refractive surgery, they acknowledged they look at some elements more closely. "I think it's important to obtain topography from a few different devices to look for consis- tency and take advantage of the pros and cons of different devices," Dr. Kugler said. Dr. Williamson makes sure the refractive surgery procedure patients say they had matches up with their topography, as it can impact the IOL decision making. Dr. Kugler mentioned using the HD Ana- lyzer (Visiometrics) and iTrace (Tracey Technol- ogies) because they provide information about lens density, light scatter, and the patient's vision quality. Dr. Williamson said patients might come in for a LASIK touch-up but really have dysfunctional lens syndrome or early cataract; the HD Analyzer can identify this and show the patient that the lens is the source of their problem, not the cornea. Dr. Kugler more closely analyzes the an- terior and posterior curvature of the cornea in Setting the stage for successful cataract surgery in the prior refractive surgery patient At a glance • Preop diagnostics in post- refractive surgery patients require a closer look to make informed implant decisions. • Prior refractive surgery makes IOL power calculations and hitting end targets trickier. • Watch out for reduced visual quality due to higher order aberrations. • Setting patient expectations with this group is more important than ever because they are more likely to expect spectacle independence and a LASIK-like result.

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