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Lisbon, Portugal?Conductive keratoplasty (CK) achieves improved near vision in patients with presbyopia who have undergone a successful previous LASIK or PRK procedure. CK is the next logical refractive step for these patients as they age and want to remain free of spectacles, according to Daniel Durrie, MD.
Another advantage is that CK sets the stage for implantation of accommodative IOLs when the need for cataract surgery arises, he explained at the annual meeting of the European Society of Cataract and Refractive Surgeons.
"The important finding right now is that surgeons who have been performing CK in their practices have been finding that one of the best patients who qualifies for CK is one who has had successful LASIK or PRK in the past. These patients have had their distance refractive problems solved and now, about 5 years later, they are developing near vision problems. Considering that 10 million individuals have undergone laser eye surgery, with the aging of this population, the common inquiry from patients is about the next step in refraction to address presbyopia and remain independent of glasses," Dr. Durrie said.
The study included 27 patients aged 40 years or older who received conservative treatment with CK, according to Dr. Durrie, that is, eight spots at an 8-mm optical zone, which is the least CK treatment done.
Three months after treatment, the mean uncorrected near visual acuity was 20/39, with 7.4% of patients seeing 20/20 or better uncorrected at near; 40.7% had 20/30 or better, and 70.4% had 20/40 or better. The mean sphere was –0.75 D and the mean cylinder –0.51 D. The incidence of glare, halos, or unclear vision was very low postoperatively.
Dr. Durrie recounted that patients went from wearing glasses for near 52% of the time preoperatively to 10% postoperatively. They reported dramatic improvements in their ability to see at near and to perform common visual tasks.
"We found that this treatment was very safe and effective. There were no adverse effects on the LASIK flap and there were no unusual occurrences during the surgery. The surgery proceeded exactly like our standard CK procedure. We also found that the degree of treatment was conservative and all patients had improvement, but in some cases more treatment is called for," he said. Dr. Durrie is associate clinical professor, Kansas University Medical Center, Kansas City, and is in private practice in Overland Park, KS.
He explained that surgeons are now considering the degree of treatment in terms of how much correction the patient wants. "For example, in a patient with an occupation that requires a lot of near vision, I use a more aggressive treatment, eight spots at 7 mm. Those patients who need a moderate correction may be treated with eight spots at 7.5 mm. In a patient who previously had monovision and is slightly myopic in that eye, the surgeon might be conservative and apply eight spots at 8 mm," he explained.
Impact on clinical practice
Dr. Durrie commented that CK is becoming the core procedure that makes him a comprehensive presbyopic surgeon because of its marketing potential. "CK is the procedure that is appropriate for patients with plano presbyopia who want to become spectacle-free during their normal activities, such as reading a restaurant menu, cell phone, or a newspaper. The surgeon can do the procedure on one eye with a minimal amount of surgery, solve the visual problem, and have a very satisfied patient.
In his practice, however, future refractive options are a topic of discussion even as the patient is considering CK.
"Undergoing CK does not mean that the patient will not need another refractive procedure with aging. A year or so after the initial CK, he or she may need an enhancement or may graduate to implantation of a presbyopic IOL, such as ReSTOR (Alcon Laboratories), ReZoom (AMO), or a crystalens (eyeonics)," Dr. Durrie said.