EyeWorld Asia-Pacific September 2011 Issue

40 EW CORNEA September 2011 Corneal approaches to presbyopia: Creating multifocal corneas by Enette Ngoei EyeWorld Contributing Editor EyeWorld takes a look at corneal approaches to presbyopia treatment that have been successful in Europe A t present, monovision LASIK is the only FDA- and Health Canada-approved corneal procedure for presbyopia treatment, according to W. Bruce Jackson, MD, professor of ophthalmology, director of refractive surgery, University of Ottawa Eye Institute, Ottawa, Ontario, Canada. Routinely performed in presbyopia patients who have not developed cataracts, monovision LASIK creates a distance focus in the dominant eye and a near focus in the non-dominant eye. Newer procedures presbyLASIK and INTRACOR (Technolas Perfect Vision, St. Louis, Mo., USA), however, create multifocality in the cornea. PresbyLASIK is performed with an excimer laser while INTRACOR utilizes the femtosecond laser. Multifocal LASIK In presbyLASIK, surgeons reshape the cornea into different zones for near, distance, and intermediate vision, allowing patients to regain good vision at all distances. The procedure is indicated for any potential refractive surgery patient with presbyopia who hasn’t developed cataracts and especially if the patient also has astigmatism because excimer laser ablation presents the most accurate approach to astigmatism correction. PresbyLASIK can be preformed in eyes previously implanted with a monofocal IOL. “We did research on [presbyLASIK] and found that in the hyperopes that we treated, we got very good results,” Dr. Jackson said. But without approval in North America, Dr. Jackson said what is happening primarily is surgeons are trying different presbyLASIK techniques with an off-label approach. Meanwhile, surgeons in Europe are performing much more presbyLASIK, and there they have more flexibility with their lasers, Dr. Jackson noted. There are a number of programs that have been developed to do presbyLASIK in Europe, he said. Some surgeons create a central zone for near vision, surrounded by a peripheral zone for distance vision (central presbyLASIK); others create a central zone for distance vision and the periphery is ablated for near vision (peripheral presbyLASIK). Still others are treating the dominant eye for distance and the non-dominant eye with a sort of blended vision- it’s different from monovision in that they have more range for distance and near created by altering the spherical aberration, Dr. Jackson explained. “There are a number of approaches that surgeons are using, but [presbyLASIK] certainly does enhance near vision,” he said. In fact, studies in Europe have shown presbyLASIK to provide good distance and near vision. Some surgeons have reported patients achieving bilaterally 20/20 (6/6) or better for distance and J3 or better for near with a majority of satisfied patients. Experts note that careful patient selection is key for good outcomes. If patients are unsatisfied, presbyLASIK is reversible with a wavefront laser treatment. Hiroko Bissen-Miyajima, MD, PhD Professor and Department Chair of Ophthalmology, Tokyo Dental College Suidobashi Hospital 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0061 Japan Tel. no. +81-3-5275-1912 Fax no. +81-3-5275-1912 bissen@tdc.ac.jp W e are still searching for the most ideal correction for presbyopia by either corneal or lens procedures. The discussion of presbyLASIK and monovision LASIK is similar to that of multifocal intraocular lenses and monovision with monofocal IOLs.There are two ways of achieving good uncorrected distance and near visual acuities: One is through the creation of bifocal function in each eye, possibly enhancing visual function with binocular conditioning, and the other is through the simple optical performance of each eye, increasing the depth of focus by creating different states of refraction. These two different approaches have benefits and drawbacks. According to Dr. Jackson’s information, the desired results by presbyLASIK were achieved, especially in Europe where off-label use is accepted. We can also use the off-label technology in Japan, and I have personally experienced happy hyperopic patients following this procedure. As Dr. Hamilton mentioned, the concerns for presbyLASIK are the regression of the effect, the possible problem of determining the appropriate IOL power due to the complicated corneal shape, and visual function following the IOL implantation. The concept of the central presbyLASIK or the peripheral presbyLASIK is similar to that of the refractive multifocal IOL with bull’s eye design. Each patient has a different preference and it will be difficult to reach one solution. Another procedure with femtosecond laser: IntraCOR also changes the corneal curvature. The idea of not penetrating the corneal epithelium is attractive. Although Dr. Holzer mentioned no complication over 2 years, the possible opacification of the laser-treated area is a concern, since corneal transplantation will be considered in such a case. In addition to these exciting corneal procedures, different types of accommodative IOLs have been developed. There are so many options for treating presbyopia now compared to 10 years ago. We would like to see the further development of each procedure and hope to have an ideal one that can guarantee a sufficient effect for every case and stable correction for the long term. Editors’ note: Prof. Bissen-Miyajima is a consultant for Alcon (Fort Worth, Texas, USA/Hünenberg, Switzerland), Hoya (Tokyo, Japan), and Abbott Medical Optics. Views from Asia-Pacific