Dr. Patricia Yarberry Allen is a collaborative physician. Her patients, she believes, will be her best partners in providing diagnostic information—as long as they are asked the right questions. She also believes in consulting with the best medical minds on issues that require specialization or unique clinical experience. This week, she has asked Dr. Leila Rafla-Demetrious, an Assistant Professor of Ophthalmology at New York–Presbyterian Hospital, Weill Cornell Medical College, to discuss the benefits—and hazards—of the LASIK procedure.
Dear Dr. Pat,
I am a 60-year-old woman who has always worn glasses for distance, and I now need glasses for reading as well. I am sick of wearing multiple glasses. My local ophthalmologist is now doing LASIK. He recommended that I have this procedure and told me that I would no longer need glasses for distance and driving.
He told me that I have no cataracts or glaucoma. Is it a good idea for me to have this surgery?
You have asked such an important question. Vision does diminish over time, and it is reasonable for patients to want a quick fix. The massive public-relations pitches for LASIK procedures began over a decade ago. “Such a simple procedure.” “We do thousands of these procedures in our suburban office every year.” “Give up ugly glasses and expensive contacts that require constant replacement and are such an annoyance.” The PR machines never discussed the side effects and the procedures performed on people who were not candidates for LASIK; only recently have ophthalmologists gathered enough data to understand the long-term implications for aging eyes that have been subjected to the LASIK procedure. I always tell patients about any surgical procedure, “There are no minor surgical procedures, just minor surgeons who refer to surgery this way.”
I have asked Dr. Leila Rafla-Demetrious, an Assistant Professor of Ophthalmology at New York–Presbyterian Hospital, Weill Cornell Medical College, to discuss LASIK and your question. Her special interests include the diagnosis and treatment of glaucoma and anterior segment diseases.
Dr. Leila Rafla-Demetrious Responds:
The short answer is “No, this particular procedure is probably not right for you.” The longer answer is much more involved, and involves understanding what LASIK is about, and also a little about the natural aging process of the eye.
LASIK, or “Laser-Assisted In-Situ Keratomileusis,” is a surgery in which the cornea is reshaped to correct one’s refractive error, and thus enhance vision. A refractive error means that the natural focusing system of the eye is either too strong or too weak, and thus light images do not fall into the back of the eye correctly; this creates either myopia (nearsightedness) or hyperopia (farsightedness) or astigmatism (fig. 1). In LASIK, a specially trained eye surgeon makes a partial-thickness flap in the cornea, which is the clear window of the front of the eye, and uses an excimer laser to remove some corneal tissue (fig. 2). The flap is then replaced into its former position, and the cornea now has a new shape thanks to the removal of some of its tissue; the refractive error is thus eliminated or greatly reduced. As a result, LASIK can help one get rid of, or at least significantly lessen, the dependence on distance glasses or contact lenses. About 700,000 LASIK procedures are done in the U.S. every year.
(A) normal eye—emmetropia; (B) myopia; (C) hyperopia; (D) astigmatism
Having LASIK done involves several key preoperative steps on the part of the surgeon and the patient. Prior to performing, or even considering, surgery, the refractive surgeon will measure and topographically map the shape of the cornea, in order to accurately program the excimer laser. A prospective patient may be asked to stop wearing soft contact lenses for several weeks prior to measurement, as lenses can deform the shape of the cornea; people with hard or gas-permeable contact lenses may have to discontinue them for even longer. The surgeon will also do a detailed exam of the eye, and look particularly at the eye for signs of lid inflammation, previous corneal scarring, an irregularly-shaped or very thin cornea, or dry eye, all of which can negatively impact the visual outcome after LASIK. The surgeon will also inspect carefully for other potential conditions, such as glaucoma, cataract, congenital eye disorders, and retinal disease; these conditions may preclude being considered for LASIK.
The best candidate for LASIK is an overall-healthy person over the age of 21. One’s prescription should be stable for at least a year, and people with conditions that can cause a fluctuation in the status of their eyes are excluded. These conditions include diabetes, pregnancy, and autoimmune diseases like rheumatoid arthritis and lupus. States of immune deficiency like HIV infection, or the use of immunity-modulating medications like steroids, are also reasons for exclusion, as they can affect wound healing. Finally, chronic ocular diseases like glaucoma, cataract, inflammatory disease, and retinal diseases are bases for exclusion, as they can both affect visual outcome, and can also be exacerbated by the actual LASIK procedure.
LASIK can correct refractive errors between -14.00 diopters and +6.00 diopters, and can also correct astigmatism of up to 6 diopters. The higher the refractive error, however, the less likely that the uncorrected vision will be 20/20, and a prospective candidate should discuss expectations in detail with the surgeon. In addition, other considerations should also come into play when discussing visual outcomes. LASIK does not correct for presbyopia, which is a normal condition that starts to affect most eyes over the age of 40. It is a stiffening of the natural lens of the eye, and can make focusing on near objects increasingly difficult. Thus, even after LASIK, people over the age of 40 will eventually need reading glasses. To this end, many surgeons will discuss the possibility of monovision. This is when one eye is corrected for clear distance vision, and the other is purposely left nearsighted, to maintain reading ability without glasses. As strange as it sounds, it does work for some select people who are willing to compromise a bit on sharp bilateral acuity.
Lastly, as one might expect with surgery, there are perioperative risks, such as corneal flap problems, infection and corneal haze, as well as other potential lingering negative side effects. These should be discussed in detail with your ophthalmic surgeon, but they include common issues such as an increase in dry eye symptoms and increased light sensitivity. Some people experience fluctuating vision over the first few months, and decreased low-light vision. Glare and haloes in the face of oncoming lights can also be a problem, and may make night driving especially troublesome. Also, due to a surgically-thinned cornea, the eye will remain at increased risk in traumatic situations, and people involved in contact or ball sports should be prepared to wear protective eye gear when involved in such activities.
So, Angela, let’s get back to your question of whether you are a candidate for LASIK. I would strongly advise against it. Even if you are healthy, and without a chronic eye disease like glaucoma, you are in an age group where you would not be best served by LASIK. I’m happy to hear that your eyes are healthy, but I would guarantee that you do have some degree of lens aging, aka cataract. As you may know, a cataract means that the lens is no longer crystal clear. Even if one’s corrected vision is still excellent, that change is still going to be there, to some extent, in a 60-year-old eye. The process of any intraocular surgery tends to further enhance the formation of visually significant cataracts, and LASIK is no exception. While published data is difficult to find on this phenomenon, anecdotal data abounds. I have personally seen many patients in their forties and fifties who had LASIK years ago and are now suffering from the effects of premature cataract formation. To make matters worse, cataract extraction does become somewhat trickier post-LASIK. Not only does the cataract surgeon have to be mindful of previous corneal surgery when planning surgery, the measurement of intraocular implants becomes much less precise. Many patients who had LASIK years ago do not have any preoperative corneal measurements on record—information which is vital when selecting a lens implant. That uncertainty can make the refractive outcome of cataract surgery, normally fairly straightforward, much less predictable.
The good news is that at your age, there are options other than LASIK to improve your vision without having to deal with multiple glasses. An easy solution is contact lenses; even if you’ve never worn them, it is never too late to try. Bifocal and monovision contact lenses are improving all the time, and the right contact lens specialist can help find a fit that works for your lifestyle. And, of course, there is cataract surgery, which can very much function like a refractive surgery. Standard lens implants can correct you well for a single distance, over a very wide range of myopic and hyperopic refractive errors, and to a lower degree for astigmatism. If you are really very committed to never needing any glasses, the newer technology of multifocal intraocular lenses offers an even broader range for visual correction, as they can correct for both distance and near vision in the same implant. Of course, before heading into any surgery, the merits and drawbacks of all potential solutions should be discussed with your ophthalmologist, so as to come up with the best plan for you and your eyes.
Leila Rafla-Demetrious, M.D., is a board-certified ophthalmologist. She is fellowship-trained in the medical and surgical treatment of glaucoma, a potentially blinding disease. She also sees and treats general ophthalmologic medical and surgical conditions. Dr. Rafla-Demetrious performs cataract surgery, as well as other anterior segment procedures. She has been a proud part of the Ophthalmology service at Weill-Cornell Medical Center at Presbyterian Hospital for over eleven years.