Is LASIK Safe?

by David A. Wallace MD

Without a doubt, this is one of the most important questions one can ask as a part of the process of considering laser vision correction care.  Government regulatory agencies like the Food and Drug Administration ("FDA") desire to review scientific information as a part of their approval (or denial of approval) processes.  These organizations ask the question, "Is LASIK safe enough to be made available to the general public within the U.S., using specific equipment?"  That is a rather different question than each individual asks when they inquire about having such care.  For you, the most important question is, "Is LASIK safe for me?"  Recognize that this is a different question, and requires different information.  The answers are generally very positive but somewhat nuanced, and require more than "30-second sound bite" answers.  On this page I will review the available information and offer my candid personal appraisal.

Some history may be helpful here.  Laser vision correction was first performed in 1988, using the method known as PRK (surface treatment).  LASIK (applying the treatment underneath a thin protective flap of superficial corneal tissue) was first done in either late 1991 or early 1992 outside the US, and became the preferred and predominant procedure for this purpose among the community of surgeons outside the US by 1994.  Lasers for use in PRK were first approved by the FDA in late '95, so it is only after this date that treatment became widely available within the U.S.  By 1997 LASIK had become clearly the predominant procedure in the U.S., in terms of sheer volume.  To date, approximately 20 million eyes have received care in the world (that would be roughly 10 million people, since most have both eyes treated).  Currently, it is estimated that approximately 700,000 new patients have LASIK each year in the US.  LASIK has become the most popular elective surgical procedure in the world.  I do not think this happened by accident, or as a result of any haphazard or reckless endeavors by those like myself that have dedicated our careers to doing the best work technically and humanly possible.

While LASIK may be tremendously beneficial for the fast majority of people who receive treatment, it is far from a *perfect* procedure.  In a very small number of cases, bad things can happen.  Typically these fall into the following categories:

  • Glare, halo, and/or decreased contrast sensitivity, producing reduced quality of vision at night (note: this is largely a legacy issue, having been substantially resolved by incorporation of pupil-tracking systems and wavefront technology, see Advanced Laser Optics);
  • Treatment to patients that were not "good candidates" for one reason or another (thin cornea, asymmetric or warped cornea, keratoconus, pre-existing corneal pathology) (see High Astigmatism and other reasons for Non-Candidacy);
  • Reduced corneal nerve sensitivity, leading to "dry eye" syndrome, or ocular surface disease (see Optimizing Eye Comfort and Managing Dry Eye);
  • Unfulfilled expectations (doctors or their staffs promising too much, or not communicating effectively with patients before and after treatment, especially if adverse consequences or complications were encountered);
  • Unrealistic expectations by some people seeking this care;
  • infection (particularly poor results usually associated with unusual organisms)
  • Very rarely, severe inflammation under the LASIK flap

Any of the above adverse consequences can compromise eye comfort, visual quality, and overall ability to function comfortably in one's daily activities. Extremely rarely, in some individuals, it has apparently led to profound depression.  Best estimates are that these very adverse events occur in approximately 1 in 15,000 cases.  The average person would look at these odds and rightly conclude that the risk of this happening to them is very low.  But for the people affected, these problems are very significant (for them, the "complication rate" is 100%).  Some surgeons are not equipped to handle these problems, or are dismissive of them; which if anything makes the problem worse.

In late April, 2008, the US FDA held a post-market review hearing addressing the safety of LASIK.  This created substantial media coverage, with everyone asking, "Is LASIK Safe?"  Links to the various news segments aired or printed by the major US network news organizations are listed at the bottom of this page.

It is noteworthy to me that the FDA hearing was supervised by the Office of Radiologic Safety and Health.  In all the testimony, and in all our years of doing excimer procedures, there has never been a shred of evidence that the radiation itself, or the consequences of radiation, cause any noticeable adverse impact to ocular tissues.  There is no suggested association between excimer treatment and cataracts, retinal disease, corneal endothelial compromise, glaucoma, etc.  To me that alone is fairly impressive.  I am aware of the work of some investigators (Dawson and Edelhauser) documenting apparent keratocyte density decrease in corneal collagen after treatment; but I do not yet appreciate any visual or clinical significance to these findings.

Nobody at the FDA hearing addressed the issue of neuro-adaptation and the importance of some degree of adaptability after vision correction care.  Human vision is a complex function involving the eyes, the visual pathways, and the vision-processing center of the brain (located mostly in the occipital cortex).  Even with a new (or updated) pair of eyeglasses or contact lenses, the brain must learn to adjust or adapt to the new optical prescription.  Certainly this is true after laser vision correction care as well.  Some people may be less capable in the neuro-adaptation arena, and this may produce adverse experience even if the surgery was rendered in a technically meticulous and perfect fashion.  Someone with poor neuro-adaptation ability, who is also psychologically fragile, can perhaps be tipped toward depression; with secondary consequences.

At the FDA hearing, nobody talked about unintended consequences of care.  There should be a “law of unanticipated consequences” and it should apply to economics, politics, and of course medical and surgical care.  An unintended consequence can be very remote from the initiating event, such as the fact that those 6-pack plastic rings holding aluminum cans together can get into the ocean, and apparently kill dolphins.  The introduction of Penicillin to medicine launched the antibiotic era and propelled medical care forward, but also caused some deaths and severe allergic reactions.  These are both examples of unintended consequences, occurring with a very low (but not zero!) frequency, on the scale of 1 in several hundred thousand or 1 in a million.  Excimer laser treatment to corneal collagen for the purpose of optical sculpting, as good as it is, also cuts superficial corneal sensory nerves.  In the overwhelming majority of instances, these nerves grow back nicely.  But in extremely rare cases, they do not grow back well enough to maintain ocular surface health, tear function, and comfort.  This is an example of a rare unintended consequence of laser treatment. 

Military service personnel have been studied extensively in the context of having laser corrective surgical care.  The outcomes in this group are extremely good.  But military personnel are perhaps not the best group from which to draw any conclusions about the potential problems of laser vision correction.  Theirs is a culture where success is hyper-valued, and anything less is barely tolerated.  The military does not want to hear complaints any more than most civilian LASIK surgeons.  But the incentives in the military are huge compared to the civilian sector.  Imagine the motivation for an aspiring Naval pilot:  The Navy will pay for him (or her) to have vision correction care, then offer flight training if visually (and otherwise) qualified, at immense cost and value to the pilot, then offer to let that aviator fly military aircraft worth tens or hundreds of millions of dollars.  Now, who is going to complain about a little glare, particularly if it is known that complaints go into their personnel file?  The statisticians would definitely call this a “bias of ascertainment”.

Nobody at the FDA hearing talked about the fact that governments including ours adopt a caveat emptor ("buyer beware") attitude toward commerce, which profoundly influences medical care, not always in a good way.  In fact, I now feel the caveat emptor influence at all major ophthalmology and refractive surgery meetings, and it irritates me to no end.  The high-priced nonsense we are sold by industry does force us to change the nature of our practices; it compels us to pass along higher fees for diagnostic studies and overpriced technology to our patients.  In a caveat emptor world the arbiter is not quality, or success, or even low morbidity, it is the crude index of revenue generation.  In our industry, now, money talks louder than quality, decency, honesty, integrity, or results.  Unless we figure out a way to escape the grip of quarterly earnings reports for publicly-held companies (and their private-equity counterparts), we are doomed to subvert any consideration of other items to this stern taskmaster.  I think at some fundamental level, this is what corrupts the delivery of excellent laser vision correction care to the appropriate patient.  No surgeon receives any monetary compensation for saying “you’re not a good candidate.”  But there may be surgeons chasing marginal cases to pay bills.

Perhaps FDA and government need to do more than just giving lip-service to the occasional very poor or unexpectedly bad outcome.  Perhaps we surgeons do, too.  I think one of the major findings to come out of the FDA hearing is that we need better reporting methods so that patients with unsatisfactory or undesirable results can be identified.  They certainly should not be marginalized, dismissed, or swept under the rug, however convenient that may be for the average surgeon and practice.

And, frankly, the FDA needs to shift a little bit, too.  They need to stop treating US surgeons like idiots, forced to use outdated technology for years while the rest of the world moves forward.  This applies to ablation algorithms, UV cross-linking, presbyopic lens designs, and many aspects of what we do.  Ultimately this foot-dragging creates a backwater mentality which absolutely does not serve the interests of technology, or of patients, or of good care in the modern era.

Ultimately I believe that a public dialog is good for the profession even if the loudest voices are not the happiest ones (that’s usually how it works).  The laser vision correction industry needs better accountability; surgeons need better accountability, and ultimately the public wants better results for all who contemplate elective care like this.  I’m clearly a small voice here but hope that we represent what is possible as “best of breed” vision correction specialists.

It’s reassuring to know that the overwhelming majority of people we care for are immensely happy with the results of their care.  That should not excuse or dismiss the suffering of the extremely rare individual who is not happy; nor should it diminish our efforts to remediate/correct/improve the lot of those who now feel poorly-served.  But there are far too many providers who would sooner feel complacent, looking only at the “good news” and the happy patients in their practice, than face the harsher reality that, while good for the great majority, LASIK is often far from perfect for a select few.  We need to devote greater effort to that small group for sure, and ultimately that’s what the FDA hearing hopes to achieve.

 

 

    •  
Schedule your Los Angeles LASIK Consultation at LA Sight