Is Refractive Surgery Becoming Lens Based?
Based on my personal experience, I believe it is a good possibility that refractive surgery may well become lens based.
Multifocal IOLs are increasingly used in both cataract and refractive surgery. Cataract surgery is now performed on younger patients who are well educated about the possibility of gaining spectacle independence with the procedure. Because they are more active, the prospect of being less dependent on spectacles to do everyday things becomes attractive. Even in the absence of a significant cataract, lens replacement with a multifocal IOL is an increasingly popular alternative to laser refractive surgery.
Premium refractive surgery centers attract older presbyopic patients, and LASIK may be less than optimal in providing spectacle independence to this clientele. Unlike LASIK, clear lens extraction and implantation of a multifocal IOL allows unaided distance and near vision, takes away the need for monovision, results in less secondary dry eye, and provides permanent refractive stability.
So often have we performed LASIK on patients aged in their 50s or early 60s, only to find them returning within 5 years with either hypermetropic refractive drift or a myopic shift from nuclear sclerosis. Then what? Do we recommend a laser enhancement to buy just a little more time, or do we expedite cataract surgery to finish the job once and for all?
FROM ARRAY TO RESTOR
The first widely available multifocal IOL was the Array (Advanced Medical Optics, Inc., Santa Ana, California). It was a refractive, multizonal, multifocal lens with the center geared to distance vision. Unfortunately, it was associated with a high degree of unwanted visual aberrations such as halos and glare. Small pupils obscured the reading portion of the lens, causing some people to lose the ability to read at close rangeunless they wore spectacles.
Although the technology of the Array has improved, much attention is now drawn toward diffractive multifocal IOLs. The lens receiving the most attention is the Restor (Alcon Laboratories, Inc., Fort Worth, Texas), and both US and international studies have confirmed the benefits of this technology over older multifocal models.1 The diffractive grating design on the front surface minimizes unwanted visual aberrations (eg, halos and glare during night driving) with large pupils, yet it still allows near vision. The near vision improves with a smaller pupil, andas expected naturallybrighter light facilitates unaided vision at a close range.
Additional features of the Restor that should not be overlooked are its (1) single-piece AcrySof platform (Alcon Laboratories, Inc.), (2) composition from the most widely used IOL material in the world, (3) yellow chromophore to protect the macula, (4) ease of implantation through wound sizes as small as 2.0 mm, and (5) square-edge design that minimizes posterior capsule opacification.
In my experience, the Restor works best if implanted bilaterally, and patient selection remains important. Presbyopic hypermetropes who have lost not only their near vision but their unaided distance acuity, do best. Astigmatism interferes with the function of the lens, and it is best to avoid implantations in patients with significant cylindrical error. The lens will not fulfill its obligation to the patient if concomitant macular pathology is present. In younger patients, premacular fibrosis needs to be excluded.
Very rarely, even with good patient selection, the quality of vision with multifocal lens technology is suboptimal. In this case, patients do better with a monofocal implant.
In my series,2,3 87% of bilaterally implanted Restor patients were spectacle independent 6 months postoperatively. Unaided distance vision was excellent, and patients could also read fine fonts without magnifiers. They may have to sit closer to computer screens to optimize their view of fonts, but they are able to do it without spectacles. Patients are told that, at worse, they may need to wear magnifiers to read in poor light or to optimize intermediate vision (eg, when sitting at computer screens).
My practice attracts presbyopic patients who have difficulty tolerating progressive lens spectacles. They dislike having to find the sweet spot within the lens to view an object at a particular distance, and they are irritated by the narrow corridor of clear vision in the center of the lens with distortion at the sides.
DRAMATIC PRACTICE BUILDER
What joy patients derive from being able to read menus, see price tags, put on eye make-up, read short message services messages (ie, text messages) on their mobile phones, and still be able to drive and watch televisionall without their progressive spectacles. Multifocal IOL technology has allowed our patients to experience this freedom, it and has proved to be a dramatic practice builder. My presbyopic practice has now grown to a point where I wonder whether I should not just call myself a refractive lens specialist and take advantage of the giant presbyopic market out there.
We have all heard it said that the way of refractive surgery may well become lens based. Now, I am starting to believe it!
Con Moshegov, MD, is Director of Perfect Vision Eye Surgery, in Sydney, Australia. Dr. Moshegov states that he occasionally receives study and travel grants from Alcon Laboratories, Inc. and Advanced Medical Optics, Inc. He may be reached at firstname.lastname@example.org.
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