What If I’m Not a Good Candidate for LASIK?

Scott Grealish M.D.
EyeHealth Northwest Deluxe Lens/Cataract Specialist
Portland, Oregon

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Breaking the news…

Since 1998 when I began performing LASIK surgery, I’ve seen thousands of patients in consultation, each hoping that they would qualify as “good candidates” for LASIK. I realize it takes a fair bit of courage for patients to meet with any surgeon for elective surgery (which by definition you don’t really need), even for an extremely safe and comfortable procedure like LASIK. After all, no one really wants eye surgery; they just don’t want their glasses or contacts. No wonder emotions can run high if your surgeon identifies something “not quite normal” on your exam, which makes you potentially “not a good candidate” for LASIK. After years of thinking about getting LASIK and finally mustering up the money and courage to move forward, it can be devastating to hear any news less than the best. It’s understandable then, that when patients hear the “news” that they might not qualify for LASIK, the rest of the consultation with the surgeon might be hard to process and remember (it’s always nice to bring a second set of “ears” to your consultation for this reason). My goal in this article is to provide some additional information for the “less than ideal” patients seeking LASIK in hopes that they will be better equipped to work through the issues with their surgeon as informed partners in the surgical decision making process.

Risks vs. Benefits

As any seasoned surgeon realizes, the vast majority of patients seeking LASIK are “excellent” candidates for the procedure. However, in reality patients typically range from “ideal” to “poor” candidates depending on the specifics of their vision and the health of their eyes. Fortunately, current technology is so good that even less than “ideal” candidates can often have very successful and safe surgery. It’s important for surgeons and patients to engage in extra discussion in these cases regarding the decision to go forward with surgery when there may be extra risk. Analyzing and explaining the risks vs. benefits for a given patient is part science and part the art of medicine. My experience as a surgeon and my interaction with colleagues over the years has led me to formulate some guidelines I use to help counsel patients on their candidacy for LASIK. I hope these will help patients understand the complexity of the LASIK decision-making process surgeons must utilize for each patient. In the end, only a detailed consultation with your surgeon can help you decide if LASIK is right for you. Lets look at some of the common issues that can create a “less than ideal” scenario for LASIK.

“Garbage in, garbage out”

Many Lasik candidates have a history of wearing contact lenses and therefore may have contact lens induced dry eye and /or contact lens induced warping of the cornea (the cornea is the front window of the eye where contact lenses are placed and LASIK is performed). Both factors often lead to “abnormalities” on our screening tests that can resolve over time by not wearing the contacts and/or treating the dry eye. Since the key tests measuring the shape of the eye rely on an adequate layer of tears coating the surface of the eye, any tear deficiency can give false readings. Many contact lens wearers have lost sensitivity on their corneal surface from years of wearing contacts. They often don’t complain of feeling dry, even when the doctor finds significant signs of dry eye on examination. Before making real conclusions about your eyes, it is often necessary to discontinue contact lenses and treat dry eye for some time before final testing.

This is an example of testing for a healthy corneal shape for LASIK, and possibly getting false readings from a separate problem, dry eye. In some cases the shape becomes “normal” when the dry eye is treated and the patient who was initially told they might not qualify LASIK can become a suitable candidate for successful surgery. Their initial testing would fall into the “garbage in, garbage out” category after the second “normal” testing provides a good reading for their eyes.

How normal is “normal”?

In reality, we now test so many variables when screening for surgery that it is becoming “normal” to see one or more tests come out “abnormal”. This is because no single test is perfect. This can get tricky to explain, but is worth understanding so stick with me here. One way to evaluate the quality of a test is called sensitivity. If a test is 90% sensitive, when you test 100 people who have a disease, the test will correctly identify 90 of them and miss 10 of them, something we call false negatives. Another way to check test quality is called specificity. If a test is 90% specific, when the test finds 100 people have a disease, 90 of them will actually have it and 10 will be false positives. In the realm of testing for risk before Lasik surgery, the most critical tests involving the shape of the cornea are actually less than 90% sensitive and specific in many cases. Surgeons are rightly more concerned with missing abnormalities, and therefore many of our tests are quite sensitive, but not specific enough, i.e. they read abnormal in too many normal cases where no real disease is present. So in our clinics, where we test over 20 variables before surgery, we in fact expect that some of the tests might be read as “abnormal”, when in reality, the doctor has no reason to think any real disease exists. As our technology for screening patients has expanded, so too has our rate of false diagnosis for potential corneal problems. So why bother with all the latest testing? More tools have allowed us to be more sensitive in our screening so that hopefully we will never miss that rare patient that truly does have a corneal disease and therefore should not have Lasik surgery. The key to sorting out who should proceed with surgery is the appropriate interpretation of the whole picture by an experienced surgeon. The take home message here is that with some understanding of the concept of “false” testing, you may better understand your surgeon’s explanation of how your “abnormal” test may really be “normal”.

“All road signs should lead to Rome”

A corollary to the “false” testing concept is that; if an abnormality of your cornea really is present and truly poses increased risk, there should be many signs pointing the surgeon to that conclusion. The more isolated the “abnormality”, the more likely it is a false result of testing. However, truly abnormal findings are typically cumulative with multiple tests indicating abnormality. They are also typically repeatable at different times, consistently pointing to the abnormality. Cumulative, repeatable evidence is the strongest kind in science.

“Precisely wrong or roughly correct”

The concept of a precise computerized testing system for evaluating Lasik candidates is naturally appealing to both surgeons and their patients. But “precision” can in fact be misleading. For example, the latest tools for assessing risk prior to Lasik utilize a grading system that incorporates a patient’s age, corneal thickness before and after surgery, prescription, and the shape (topography) of the cornea. Several of these can be measured quite precisely, like age for example. The corneal thickness before surgery (which implies strength or lack thereof) can be measured exactly, but the corneal thickness afterward is really only a rough prediction until after surgery. The shape of the cornea is determined by the surgeon’s qualitative (i.e. not numerically precise) interpretation of quantitative data (the raw numbers measured by the computer).

This lack of precision is not so much a problem as it is a real reflection of the entire process of surgeon interpretation. As an example, consider that in the best current grading system, a 27-year-old with 511-micron corneas has 0 risk points and a 28-year-old with 510-micron corneas has 2 risk points (and is therefore higher “risk”). In this case, we can conclude that the grading system is precisely right and in reality totally wrong. Those patients are likely identical in risk. An experienced surgeon would use such a system as a guide only and interpret the risk for a given patient in broader, less precise, but I would argue more “roughly correct” terms. Eye surgeons and their patients rely heavily on the latest technologies to correct vision. Indeed, the precision needed to refocus the eye can only be achieved with the most sophisticated computer guided lasers. When it comes to the decision making before surgery however, the best “computer” is a skilled, experienced, and caring surgeon who takes the time to look at the big picture and guide each patient individually to achieve their goals for their eyes.

“Treat the patient, not the cornea”

I’ve tried to describe some of the many intangibles that guide an experienced surgeon in their decision-making before LASIK. The risk/benefit equation of any surgery is just that, an equation with three variables: risk, benefit, and the balance (or ratio) of those. Even if we had perfect tools as surgeons to precisely identify risk in every case, we would still be left with the equally important tasks of identifying the unique benefits that each patient would enjoy as well as assessing what balance of risk vs. benefit each patient is willing to accept as part of the surgical experience. This is why we take into account patients visual expectations, occupations, hobbies, age, and prior ocular history as part of the decision making process. Research demonstrates that patients considering Lasik are significantly more troubled by their glasses or contact lenses than normal patients. Perhaps even more meaningful, with very few exceptions these same patients enjoy a large improvement in quality of life after surgery beyond the levels of those who continued in glasses or contact lenses. Clearly the “risks” of surgery are dependant on the sort of corneal testing and interpretation we’ve been discussing. Just as evidently, the “benefits” of surgery are unique to each patient and in the risk benefit equation may well outweigh the potential risks to your cornea. Hence the dictum: “treat the patient, not the cornea”.

“Time is money”

Finally, I would hope it is now obvious why Lasik surgery pricing varies so much in our community and in the US in general, even when everyone claims to use the “best” equipment. Adequate screening, counseling, and examination before and after surgery is time intensive even though the surgery itself is brief. This is money well spent. Amongst experts in the field, there is nearly universal agreement that the surgeon is responsible for taking the time to personally perform the preoperative evaluation and counseling as well as providing post-operative care until the patient is stable. In reality, this is far from the case in a surprising number of clinics. At EyeHealth Northwest we provide direct unlimited access to our surgeons for each Lasik patient. With 10 Lasik surgeons on staff, 24/7 access to multiple specialists is ensured, even if your surgeon is out of the office. This back up is reassuring to both patients and surgeons.

“Expert opinion requires an expert”

In conclusion, hopefully it is now clear that a detailed personal consultation with your surgeon is mandatory whether you are an “excellent” candidate for surgery or not. If you are not an “excellent” candidate, then it becomes even more critical to receive the best quality consultation from an Ophthalmologist (who are surgeons by definition, as opposed to “Optometrists” who are not) with broad surgical and medical experience. Expert consultation with your surgeon will help you make the best decision for your eyes.