LASIK, or Laser-Assisted In Situ Keratomileusis, is a widely performed surgical procedure that corrects common vision problems such as nearsightedness, farsightedness, and astigmatism. This outpatient procedure permanently reshapes the cornea, the clear front surface of the eye, allowing light to focus correctly onto the retina for clearer vision. The development of LASIK revolutionized ophthalmology by providing a highly effective and predictable method for vision correction, reducing dependence on glasses or contact lenses for millions worldwide.
The Surgical Precursor: Keratomileusis
The foundational concept of surgically reshaping the cornea originated long before the advent of the laser. This groundwork was laid by Dr. Jose Barraquer, a Spanish ophthalmologist who conducted his pioneering work in Bogotá, Colombia. Dr. Barraquer is referred to as the “Father of Refractive Surgery” for his innovative approach to altering the eye’s focusing power.
In the late 1940s, he developed the procedure called Keratomileusis, a term that translates to “cornea sculpting.” This technique involved using a specialized surgical instrument, a microkeratome, to cut a thin disc of corneal tissue. The surgeon would then freeze the removed tissue and manually reshape it on a lathe to correct the refractive error.
The reshaped corneal tissue was sutured back into place. While revolutionary, this early method was technically complex and lacked the necessary precision and predictability for widespread use.
Combining the Technologies: The Invention of LASIK
The invention of LASIK merged Dr. Barraquer’s surgical technique with emerging laser technology. The critical step involved adapting the existing Keratomileusis procedure to allow the cornea to be reshaped in situ, or in place, rather than removing, freezing, and reshaping the tissue externally. This in situ approach required the flap to remain attached, a significant technical refinement.
A patent for the general concept of using a corneal flap and laser ablation was awarded to Dr. Gholam Peyman in the United States in 1989. However, the key procedural steps defining modern LASIK were finalized elsewhere. The acronym LASIK was coined by Greek ophthalmologist Dr. Ioannis Pallikaris, who worked at the University of Crete.
Dr. Pallikaris’s breakthrough involved using the microkeratome to create a hinged corneal flap, which was lifted to expose the underlying corneal tissue. He then used the excimer laser to perform the reshaping on the exposed stroma before repositioning the flap. Dr. Pallikaris performed the first successful LASIK procedure on a human eye around 1990 in Greece, combining the precision of the laser with the flap technique for a less invasive and more stable correction.
How the Excimer Laser Works
The technological engine that made LASIK possible is the excimer laser, a device fundamentally different from traditional surgical lasers. The term “excimer” is a contraction of “excited dimer,” referring to the molecular mechanism that generates the light beam. This laser uses a mixture of noble and halogen gases, such as argon and fluoride, to produce a specific wavelength of ultraviolet light.
This ultraviolet light operates as a “cold laser,” meaning it removes tissue through a process called photoablation rather than burning it with heat. The high-energy photons in the beam break the molecular bonds within the corneal tissue, causing microscopic amounts of material to vaporize cleanly.
The excimer laser’s precision is remarkable, capable of removing tissue in increments as small as 0.25 microns, which is far less than the thickness of a human hair. This control allows the surgeon to sculpt the cornea’s surface precisely according to the patient’s prescription. By avoiding thermal damage, the laser ensures the surrounding, untreated cells of the cornea remain healthy.
From Invention to Global Standard
Following its invention, LASIK required a rigorous process of clinical trials and regulatory review to achieve widespread medical acceptance. In the United States, the procedure gained formal approval from the Food and Drug Administration (FDA) in 1999, formalizing its place in mainstream ophthalmology. This approval came after years of testing that demonstrated the procedure’s safety, predictability, and effectiveness for correcting refractive errors.
The procedure continued to evolve rapidly after its initial adoption, leading to significant advancements in both safety and customization. Advanced technologies like wavefront-guided LASIK were introduced, which use detailed maps of the eye’s unique optical imperfections to guide the laser treatment with superior precision. This customization allows for the correction of subtle visual distortions beyond a standard eyeglass prescription.
Another major refinement was the introduction of the femtosecond laser, which replaced the mechanical microkeratome for creating the corneal flap. This “blade-free” method uses ultra-fast pulses of light to create the flap with greater accuracy and less risk of complications. These technological advancements have cemented LASIK’s status as a global standard, with millions of procedures performed worldwide.