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Surgeons use procedure to offer patients improved vision quickly with few side effects
In a multicenter clinical trial, more than 90 percent of patients, when measured binocularly, had uncorrected visual acuity of 20/16 or better.
LASIK is better than ever, despite reports that have highlighted poor outcomes, most from years ago. Data actually shows that LASIK results are better than ever, and patients can expect outstanding results, with few side effects. In our practice, LASIK is thriving.
While I never promise patients a particular outcome, I am up-front that our goal is to get to better than 20/20 vision. I can say this with confidence because my colleagues and I recently reported on a multicenter clinical trial in which more than three-quarters of eyes, and more than 90% of patients when measured binocularly, had uncorrected visual acuity of 20/16 or better.1
Patients are interested to hear this. The idea of “better than 20/20” is the part of a consultation that gets them excited. Refractive surgery results have reached this point because we have seen consistent, incremental improvements in laser vision correction technology.
Wavefront-guided procedures, tighter control of laser energy and laser beam angle, and other technical improvements have greatly increased the proportion of 20/20 or better outcomes and reduced the variability in results. Newer platforms have also nearly eliminated the quality-of-vision complaints related to optical aberrations (e.g., double vision, hazy vision, disabling glare) that we sometimes saw after LASIK.
Patients have an unerring radar for a surgeon’s level of confidence. Based on my own data and what is in the published literature, I don’t have to give patients a lot of qualifiers about the results they can expect. Of course, I always warn them about possible side effects, but the numbers-and the confidence I feel-communicate that my level of concern is low.Prospective study
The study I mentioned was an investigator-initiated, post-market study conducted by Colman Kraff, MD, Stephen Coleman, MD, and myself. In all, 97 patients were enrolled in this prospective study to evaluate the results of wavefront-guided LASIK using an aberrometer (iDesign, Johnson & Johnson Vision) to guide the treatment. All subjects underwent bilateral LASIK, with a target of emmetropia. Nomogram adjustments were made as needed to bring the wavefront sphere into agreement with the manifest refraction sphere.
Of the 97 patients enrolled, 84 completed the study. Preoperative spherical error ranged from –0.25 D to –11.0 D (mean –3.83 D), with or without astigmatism of up to –5.0 D. Subjects were examined at baseline, one, three, and six months postoperatively. Ninety-seven percent of eyes achieved postop monocular uncorrected visual acuity of 20/20 or better; 77% were 20/16 or better. When vision was measured binocularly, all subjects could see at least 20/20, with 93% seeing 20/16 or better.
The mean manifest refraction at six months was –0.01 D, with a standard deviation of 0.25 D, the mean manifest cylinder was –0.21 D. At six months, about half the patients reported that their eyes never felt dry or gritty, while half said they “sometimes” felt dry or gritty. Only 4% reported more frequent symptoms. At six months, most patients also reported rarely experiencing glare, halo, starbursts, or double vision.
The rate of these symptoms decreased compared to baseline. Patient reports of starbursts declined from 15% of subjects before surgery to 1.5% after. Reports of halos decreased from 9.7% preop to 3% postop. Ninety-six percent of subjects said they could function with “no difficulty” without corrective lenses, and 97% said their quality of life had improved. Nearly all subjects (99%) said they would recommend LASIK to a friend or relative.
Although our mean postoperative manifest refraction was nearly zero, the most impressive aspect of the results is the standard deviation (SD) of 0.25 D. Standard deviation of the manifest refraction spherical equivalent (MRSE) is the way we should judge a laser system.
Let us compare two hypothetical lasers. Laser One has a mean MRSE of 0.00 D with a relatively high SD of 0.36 D. Eighty-four percent of eyes are within 0.5 D of emmetropia. Hypothetical Laser Two has an inaccurate mean MRSE at –0.3 D, but a lower SD. Laser Two also achieves 84% of eyes within 0.5 D of emmetropia.
Obviously, you would choose Laser Two, and you would program a simple nomogram adjustment of 0.3 D. You would be the owner of a system than got 99% of eyes within 0.5 D of emmetropia. The large standard deviation of Laser One is not correctable.
This is why standard deviation of MRSE should be a key measure of a laser’s performance. We know that each extra line of uncorrected vision translates into a jump in patient satisfaction. To build a LASIK practice that thrives on high satisfaction and patient referrals, 20/20 is not enough. You really need to get patient after patient to 20/15-and that is possible with today’s wavefront technology.
Robert K. Maloney, MD
Dr. Maloney is director, Maloney Vision Institute; clinical professor of ophthalmology, David Geffen School of Medicine at UCLA Los Angeles. He is a consultant to Johnson & Johnson Vision.
1. Maloney RK, Kraff CR, Coleman SC. A prospective multicenter post-approval study of wavefront-guided LASIK for myopia using a high-def Hartmann-Shack averrometer. ASCRS, 2019.