An Update on Keratorefractive Lenticule Extraction

The field of refractive surgery has undergone a transformation in recent years. The evolution from LASER IN-SITU keratomileusis (LASIK) to lenticule-based techniques, such as keratorefractive lenticule extraction (KLEX), marks a pivotal shift in the way we approach refractive correction. Today, KLEX offers significant advantages over traditional LASIK, notably through its minimally invasive approach, which preserves corneal integrity and reduces the risk of complications associated with flap creation. The refractive society has jointly decided to label all lenticule extraction procedures as KLEX. KLEX stands at the forefront of refractive technology by offering procedures that are flap-free and, hence, minimally traumatic. Unlike LASIK, where a corneal flap is created before ablating the cornea with an excimer laser, KLEX procedures utilize only femtosecond lasers to extract a lenticule from within the cornea without the need for a flap. This approach has proven to be advantageous in terms of visual recovery, patient comfort, and the possible preservation of corneal biomechanics, thereby offering enhanced stability and predictability in refractive outcomes. Several platforms now offer KLEX capabilities, each with unique specifications and technology designed to optimize the refractive correction process. This editorial provides highlights some of the leading platforms available today, including the VISUMAX 500 and 800 by ZEISS, FEMTO LDV Z8 by Ziemer, ATOS by Schwind, and ELITA by Johnson and Johnson. Each of these devices brings distinct features to the table, allowing ophthalmologists to tailor the procedure to each patient’s unique needs. KEY SPECIFICATIONS OF KERATOREFRACTIVE LENTICULE EXTRACTION PLATFORMS The VISUMAX 500 and 800 platforms by ZEISS are known for their high pulse repetition rates – 500 kHz and 2 MHz, respectively. These devices operate at a wavelength of 1043 nm, with a pulse energy range between 110 and 150 nJ, and employ a curved patient interface, allowing for greater patient comfort. Notably, the VISUMAX 800 also includes cyclotorsion compensation and an inbuilt centration system, enhancing precision and alignment during the procedure. The laser cut time on these platforms is around 10–30 s, with the VISUMAX 800 offering the fastest cutting time (approximately 10 s) due to its higher pulse repetition rate. The FEMTO LDV Z8 by Ziemer provides a high degree of flexibility with a pulse repetition rate that can reach up to 20 MHz and an energy per pulse under 100 nJ. Its flat patient interface, along with cyclotorsion compensation and a built-in centration system, provides additional stability and accuracy. However, the absence of lenticule extraction capabilities restricts its use in purely lenticule-based procedures. Schwind’s ATOS platform, operating at 1030 nm with a pulse rate of up to 4 MHz, offers an energy range of 75–135 nJ and a laser cut time of about 30–40 s. The curved patient interface, along with cyclotorsion compensation and an inbuilt centration system, ensures a smooth experience for both patient and surgeon. The ELITA platform by Johnson and Johnson Surgical Vision (JJSV) is a highly advanced machine that stands out due to its unique combination of speed and precision. Operating at 1040 nm with a pulse repetition rate of 10 MHz, the ELITA platform achieves a cut time of about 16 s, significantly faster than many other devices. With a pulse energy of 40–55 nJ and a flat patient interface, the ELITA platform is designed to optimize both comfort and precision. Its inbuilt centration system and cyclotorsion compensation further enhance the reliability of outcomes. POTENTIAL ADVANTAGES OF KERATOREFRACTIVE LENTICULE EXTRACTION OVER LASIK The advantages of KLEX over LASIK are manifold. First and foremost, by eliminating the need for a corneal flap, KLEX reduces the risk of flap-related complications, such as displacement, flap tears, or epithelial ingrowth. This flap-free approach also preserves corneal biomechanics, which is especially beneficial for patients with thinner corneas or higher refractive errors. In addition, KLEX typically results in faster visual recovery and greater postoperative comfort due to the minimal disruption of corneal tissue. Another notable advantage is the reduced incidence of dry eye symptoms postoperatively, a common concern with LASIK. KLEX preserves the integrity of corneal nerves more effectively than LASIK, which can lead to better tear production and fewer dry eye issues. Finally, as refractive surgeons, we are constantly driven to offer patients procedures that balance efficacy, safety, and comfort. KLEX has emerged as a preferred option for patients and surgeons alike due to its precise outcomes and reduced invasiveness. With the development of platforms such as VISUMAX, ATOS, and ELITA, we are witnessing a paradigm shift in refractive surgery that aligns with modern-day patient demands and technological capabilities. LOOKING AHEAD The world of refractive surgery is increasingly moving toward KLEX, fueled by advancements in femtosecond laser technology and the proven benefits of lenticule extraction. The introduction of platforms like ELITA, with its rapid cut times and precise energy modulation, exemplifies the rapid progress in this field. As we continue to refine these technologies, KLEX is poised to become the gold standard in refractive correction, offering a solution that is both minimally invasive and highly effective. With improved LASER platforms, better dissection techniques, and superior visual outcomes, surgeons are not only looking at refining visual outcomes further, but have looked at using the extracted lenticule for other potential benefits, including, customized crosslinking, femtosecond intrastromal lenticule implantation, and potential hyperopia treatment. The future of KLEX lies in continued innovation, and as clinicians, it is imperative that we stay abreast of these developments. By adopting these advanced platforms, we can provide our patients with safer, more effective options for achieving their vision goals. With each new generation of KLEX technology, we move closer to a future where refractive surgery can be delivered with unparalleled precision and safety, marking a new era in ophthalmic care.