BLOG: LASIK in 2020 – ‘State of the union’
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This third installment of the current state of LASIK looks at more data and thoughts about the future.
Sandoval and colleagues reviewed LASIK articles published between 2008 and 2015 that included clinical outcomes. All 97 relevant articles (representing 67,893 eyes) provided a positive or neutral impression of LASIK. The aggregate loss of two or more lines of corrected distance visual acuity was 0.61%, and the overall percentage of eyes with uncorrected distance visual acuity greater than 20/40 was 99.5%. The spherical equivalent refraction was within 1.00 D more or less of the target refraction in 98.6% of eyes, and 90.9% were within more or less than 0.50 D. The authors found that 1.2% of patients were dissatisfied with LASIK.
The authors concluded, “Aggregate outcomes appear better than those reported in summaries of the safety and effectiveness of earlier laser refractive surgery systems approved by the FDA. Modern results support the safety, efficacy and patient satisfaction of the procedure.”
The future of LASIK
Twenty years ago, patients considered an uncorrected visual acuity of 20/20 after LASIK a success. But can we do better? Perfect vision for many young healthy adults means visual acuities of 20/15 to 20/12. Theoretically, the limit of foveal acuity would be 20/12 for a small pupil and up to 20/5 for a dilated pupil in the absence of optical aberrations.
Therefore, future goals for LASIK may include:
higher quality visual acuity of 20/20 with fewer nighttime dysphotopsias;
"supervision" exceeding 20/20; and
correcting refractive errors and aberrations with previous refractive surgery; ie, RK, astigmatic keratotomy, automated lamellar keratoplasty, PRK or LASIK (Vestergaard).
While wavefront technology will likely expand to treating eyes with previous suboptimal surgeries, it remains to be seen if it will be a tool to achieve “super vision” LASIK.
Don’t expect super vision refractive surgery to be commonplace anytime soon. Because current trials enroll only young, healthy adults with mild refractive errors, we see better results than those in older patients or individuals with higher postoperative prescriptions. In other words, the results of custom ablations performed on average patients won’t be as impressive.
Aberrations remain hurdles
Other hurdles are dynamic fluctuations that the eye can experience over time — aberration-free eyes may not remain that way. Aberration is measured before the flap is made, plus flap repositioning creates additional aberration. Flap healing involves biological changes, and of course, any postoperative complications will also increase aberrations. Accommodation plays a role in wavefront analysis, so the eye’s focal point can affect the appearance of optical aberrations. Aging is yet another factor that increases aberration. Not every kind of optical aberration can yet be accounted for, presenting an ongoing challenge.
It appears that ongoing advances in wavefront technology will continue to drive evolutions in refractive surgery, resulting in developments that could scarcely be conceived of back in the dark ages, when surgeons were still using a knife to achieve glasses-free vision for patients.
References:
- Sandoval HP, et al. J Cataract Refract Surg. 2016;doi:10.1016/j.jcrs.2016.07.012.
- Vestergaard AH. Acta Ophthalmol. 2014;doi:10.1111/aos.12385.
For more information:
Johnston can be reached at: josh.johnston@gaeyepartners.com.
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