Laser-assisted in situ keratomileusis (LASIK) is a popular vision correction surgery that has transformed the lives of millions of people worldwide. However, the creation of the corneal flap, an essential step in the LASIK procedure, has been a constant subject of research and innovation. In a groundbreaking study, researchers have unveiled the clinical safety and efficacy of using a low-pulse energy femtosecond laser to create elliptical thin-flaps for LASIK. This advancement promises to deliver even better visual outcomes and reduced complications for patients seeking to improve their eyesight. Join us as we delve into the details of this revolutionary approach that is poised to redefine the future of refractive surgery. LASIK, Femtosecond laser, Cornea

Revolutionizing Vision Correction: Thin-Flap LASIK with Precision and Safety
Laser in situ keratomileusis (LASIK) has been a game-changer in the world of refractive surgery, offering a reliable and effective way to correct vision problems such as myopia, hyperopia, and astigmatism. One of the critical steps in the LASIK procedure is the creation of a corneal flap, which is then folded back to allow for the precise removal of corneal tissue using an excimer laser. The thickness of this flap plays a crucial role in the overall safety and efficacy of the procedure.
The Quest for Thin-Flap LASIK
Traditionally, LASIK flaps have ranged in thickness from 100 to 160 microns. However, in recent years, the focus has shifted towards creating thinner flaps, as this helps preserve the underlying corneal tissue, known as the residual stromal bed thickness (RSBT). A higher RSBT is essential to reduce the risk of a rare but serious complication called corneal ectasia, where the cornea bulges and weakens over time.
The use of femtosecond lasers, which can create flaps with high precision and predictability, has been a game-changer in achieving thinner flaps. These advanced lasers use low-pulse energy to minimize the formation of gas bubbles and other complications, making them a safer and more effective option for thin-flap LASIK.

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The Breakthrough Study: Elliptical Thin-Flap LASIK
In a recent retrospective study, researchers from Taiwan evaluated the clinical safety and efficacy of using a low-pulse energy femtosecond laser to create elliptical thin-flaps for LASIK. The study included 80 patients who underwent bilateral LASIK surgery, with flap thicknesses ranging from 85 to 100 microns.
The researchers found that the visual and refractive outcomes were consistently excellent across all the flap thickness subgroups. At the 1-month follow-up visit, an impressive 96% of eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 or better. The mean manifest spherical equivalent was also within a remarkably narrow range of -0.37 ± 0.42 diopters.
Consistent Flap Thickness and Reduced Complications
One of the standout findings of the study was the high predictability and consistency of the achieved flap thicknesses. The researchers used optical coherence tomography (OCT) to measure the flap thickness on the first postoperative day, and the results were highly consistent with the target flap thicknesses in each subgroup.
Importantly, the study also reported the absence of any clinically relevant intraoperative or postoperative complications, such as opaque bubble layer, flap striae, or buttonholes. This remarkable safety profile can be attributed to several factors, including the use of a low-pulse energy femtosecond laser, the creation of elliptical flaps with a wide temporal hinge and inverted-angle side cuts, and the precise control of the flap thickness.

Fig. 3
Optimizing Corneal Biomechanics and Reducing Ectasia Risk
The preservation of the RSBT is a crucial factor in minimizing the risk of post-LASIK ectasia. By creating thin flaps, the researchers were able to maintain a sufficient RSBT, which is essential for maintaining the cornea’s structural integrity and reducing the likelihood of this rare but serious complication.
Furthermore, the elliptical shape of the flaps, combined with the wide hinge angle and inverted side-cut, has been shown to improve the biomechanical performance of the cornea after LASIK. This optimization of corneal biomechanics helps ensure the long-term stability of the surgical outcomes and further reduces the risk of ectasia.

Fig. 4
Embracing the Future of Refractive Surgery
The findings of this study represent a significant advancement in the field of refractive surgery. By leveraging the precision and safety of low-pulse energy femtosecond lasers, surgeons can now create thin corneal flaps that provide excellent visual and refractive outcomes while minimizing the risk of complications.
This breakthrough has the potential to transform the LASIK experience for patients, offering them the opportunity to achieve clear, stable vision with a reduced risk of side effects. As the technology continues to evolve, we can expect to see even more innovative approaches to refractive surgery that prioritize patient safety and satisfaction.
Author credit: This article is based on research by Hung-Yuan Lin, Ya-Jung Chuang, Steven Wei-Hsin Chang, Pi-Jung Lin.
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