March 2019

COVER FEATURE

Refractive corrections
Considerations for patients with prior corneal refractive surgery


by Ellen Stodola EyeWorld Senior Staff Writer/Digital Editor


Topography and aberrometry obtained from the OPD-Scan III on a patient with an interest in spectacle independence after cataract surgery. She had a history of prior PRK with a moderate amount of corneal higher order aberrations, circled in bottom right box. This was the patient’s dominant eye, which did well with an extended depth of focus IOL with no plans for enhancement at this time.
Source: Brandon Baartman, MD


Choosing which implant is best for these patients

With many lenses available for those with different visual demands, surgeons have more and more options for patients who want to be less dependent on glasses. However, patients who have had prior corneal refractive surgery may require special considerations when choosing which option is best. Brandon Baartman, MD, Vance Thompson Vision, Omaha, Nebraska, and Kevin Waltz, MD, Indianapolis, discussed diagnostics, lens options, and potential postoperative issues.

Goal of being glasses-free

EyeWorld asked Dr. Baartman and Dr. Waltz to weigh in on how to approach patients who want distance, intermediate, and near vision without glasses after cataract surgery.
This is an important issue in refractive cataract surgery, Dr. Baartman said. “Patients who underwent refractive surgery in the 1990s and early 2000s are now aging into the cataract demographic, and many are still very active both in the workforce and their personal lives,” he said. “The desire for clear and functional vision independent of glasses doesn’t go away.” These patients can require a lot from a visual freedom perspective but can also be some of the most challenging due to the prior corneal surgery, he added.
Dr. Baartman said that he approaches cataract surgery the same way with all patients, regardless of refractive surgical history: How much do they want to be able to do without glasses after surgery? “Some of these patients are used to wearing reading glasses and don’t mind using them but want that LASIK-like visual outcome at distance after surgery,” he said. “Others have converted to monovision after the onset of presbyopia and plan to continue using this for spectacle freedom after cataract surgery.” He added that even though both patient groups generally wind up with a monofocal optic, the outcome is critical for their happiness, and it’s important to nail the refractive target.
Patients who are more visually demanding at intermediate and near may benefit from a multifocal or extended depth of focus optic, Dr. Baartman said. “Historically, optics that split light were not good options in the post-refractive cornea, but that has changed,” he said, adding that many surgeons have reported impressive outcomes with newer technology diffractive optics in the post-refractive eye, including LASIK, PRK, and even certain patients with radial keratotomy. “There’s a lot that goes into these patient evaluations in terms of discussion and testing, but nothing is as important as clear communication and a mutual understanding of patient goals and possible limitations of the surgery,” Dr. Baartman said.
Dr. Waltz said that he does a lot of refractive surgery and personally has multifocal lenses. The main point to understand with a post-refractive patient is they’ve already set themselves apart from the average patient. Since these patients paid extra for a certain refractive outcome, Dr. Waltz said they likely would be interested in optimizing that outcome after refractive surgery. He added that the number one criterion in these cases is patient motivation. “If they want it easy and quick and don’t mind wearing glasses, that’s a perfectly good choice,” he said. “But if someone says they love refractive surgery and was happy and want to get that back, that’s a different choice, and you can make that person happy, too.”
Dr. Waltz noted that there are a number of technical details the physician has to be aware of for these patients. If the patient has had prior refractive surgery, the likelihood that you’re going to get a good refractive outcome with the initial result is decreased. Part of what the surgeon has to understand is what the enhancement strategy will be, he said, adding that the surgeon who operates initially doesn’t necessarily have to be the one to do the enhancement, but it has to be available to fine-tune the outcome.

Diagnostics

Dr. Baartman said that some of the things he uses most frequently are topography and wavefront aberrometry to evaluate candidacy for a diffractive optic. He utilizes the OPD-Scan III (Nidek, Fremont, California) and pays close attention to the anterior corneal shape, looking for areas of irregularity that may have been the result of early technology ablation patterns, and the general size of the ablation zone. “I also use the point spread function to evaluate the presence of higher order aberrations, which I think is important to understand preoperatively,” he said. “These corneas often have a bit more spherical aberration than the normal cornea, but paying attention to the presence of other aberrations, such as coma, can help detect those patients with even small decentrations in ablation that may limit the success of multifocal lenses.” Dr. Baartman also uses the Pentacam (Oculus, Wetzlar, Germany), not only for corneal power estimations but he is also paying attention to the posterior cornea and corneal thickness.
Dr. Waltz said that he finds a high-quality topographer to be the biggest diagnostic help for him. He said that it’s important to know if the ablation is centered, if there are any areas of ablation that will change the quality of vision, and what the spherical aberration of the cornea is. “It’s important to understand that as people get older, their lens changes shape and their spherical aberration typically gets worse,” he said. If you’ve had prior surgery and as you get older, spherical aberration gets worse.

Who should not have a premium IOL

There are some findings that indicate a patient is not a good candidate for a premium IOL. Dr. Baartman said that any evidence of decentered ablation or presence of significant total corneal higher order aberrations are red flags.
While some patients are not good candidates for advanced technology IOLs, if there is evidence of a decentered ablation or other topographic irregularity and the patient is interested, Dr. Baartman said he considers using topography-guided ablations to normalize the corneal surface to improve their candidacy for the lenses. “Exam findings can challenge our ability to use advanced technology lenses, such as poor zonule support from PXF or presence of retinal pathology like AMD,” he said. “I do pay attention to pupil size as well and emphasize the possibility of photic phenomena to those patients with larger mesopic pupil diameters.”
Dr. Baartman said that it is also important to build a relationship with the patients and understand their desires, as well as their attitudes. “I think those patients who have a tendency toward perfectionism may not be great candidates, and I make sure to spend time discussing the possible drawbacks of using advanced optics,” he said. “This often helps select those who would be bothered by some of those drawbacks, such as photic phenomena and decreased contrast sensitivity.” He added that to him, the most important characteristic of a good candidate is one who has a genuine interest in as much spectacle freedom as possible, coupled with a good understanding of the refractive cataract journey. “The cornea should have minimal irregularity on the anterior surface, be free of significant higher order aberrations on wavefront testing, and a normal posterior float with enough residual tissue for a laser enhancement,” he said.

Optimizing chance for success

Dr. Waltz said that the first thing to consider is treating the ocular surface. People who are cataract age often have significant ocular surface disease, and many times, this issue can be improved with artificial tears, he said. Improving the ocular surface can help get better preoperative measurement, and you’ll be more likely to hit the target postoperatively. Another issue he mentioned was astigmatism, which he described as a postoperative “killer for quality of vision.”
Dr. Baartman said that there is good evidence that the postoperative period is a critical time for refractive cataract patients with presbyopia-correcting IOLs, and this is magnified for those with a history of laser vision correction. “These are often patients with a lot of visual demands who have undergone vision correction procedures that delivered fairly rapid results (e.g., LASIK or PRK), and the adaptation to their new optical system with cataract surgery can take some time,” he said. “I discuss the journey with these patients preoperatively but also make sure to touch on it postoperatively.” Dr. Baartman added that neuroadaptation is taking place during the first 6 months after implantation, and it’s important to maximize your availability for questions and concerns that may come up from patients.
Paying attention to and discussing the plan for addressing residual refractive error is also important to remind patients of the multi-step journey and often helps patients through the recovery. “It’s important to plan to see these patients around the 90-day mark to evaluate for presence of posterior capsular opacification, as even small amounts of capsular cloudiness can impact the performance of these optics,” Dr. Baartman said.

Editors’ note: Dr. Baartman has financial interests with Allergan (Dublin, Ireland) and Refocus Group (Dallas). Dr. Waltz has financial interests with AcuFocus (Irvine, California) and Johnson & Johnson Vision (Santa Ana, California).

Contact information

Baartman
: brandon.baartman@vancethompsonvision.com
Waltz: kwaltz56@gmail.com

Considerations for patients with prior corneal refractive surgery Considerations for patients with prior corneal refractive surgery
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