Laser-assisted in-situ keratomileusis – better known as LASIK – is a procedure that is testament to decades of technological innovation and advancement in refractive therapies and procedures, which continue to improve in the projected future.
Patented by Dr. Gholam Peyman in 1989 before receiving FDA approval in 1999, LASIK has been a prominent procedure for correcting refractive error in vision, particularly in near-sighted patients, for more than 35 years.
Alongside other current procedures, LASIK continues to be a prominent fixture for refractive correction.
Shaping the past
Columbus Lasik & Cataract Center
From the beginning, refractive correction was aimed to treat myopia, also known as nearsightedness. This is due to the condition’s effect on the eye, making it too curved or long for normal light refraction in the retina, affecting the brain’s vision processing.
Before LASIK and other laser procedures, refractive correction started in Japan in the 1930s with Dr. Tsutomu Sato. He used radial keratotomies, which called for a doctor to use a diamond blade to make incisions into the cornea’s fourth layer, Descemet’s membrane, to flatten the cornea.
While this surgery helped correct the refraction errors caused by myopia, it brought about additional complications such as corneal decompensation.
The procedure remained prominent until the 1990s despite these complications, becoming more precise for corneal shaping.
In the 1950s and `60s, keratomileusis, the medical term for cornea sculpting, came about thanks to Dr. José Ignacio Barraquer Moner of Colombia and his work on creating what would be known as anterior lamellar keratoplasty (ALK).
ALK, or the more often used, deep anterior lamellar keratoplasty (DALK), uses a microkeratome to surgically remove diseased outer layers of the cornea while keeping the rest of the cornea intact.
Though it has changed since its earliest uses, as Barraquer Moner’s student, Dr. Luis Ruiz, was among the professionals who continued to improve the microkeratome’s precision through the 1980s, with the procedure still in use today.
The 1970s and `80s saw lasers start to get introduced to refractive correction procedures, starting with heat lasers before the more precise, non-thermal alternatives were created, leading to the innovations of photorefractive keratectomy (PRK) and LASIK.
With the implementation of lasers, doctors saw the procedures’ precision and efficiency with reduced recovery time and complications, leading to their prominence as part of eye procedures.
Columbus Lasik & Cataract Center
Current procedures
LASIK and PRK are two prominent options for refractive correction laser procedures today.
PRK preceded LASIK by a few years, first performed in Louisiana in 1988 by Dr. Marguerite McDonald. The first LASIK procedure was done in 1990 at the University of Crete in Greece by Dr. Ioannis Pallikaris.
Traditional versions of these procedures do still use the microkeratome tool, but newer iterations utilize all-laser procedures. PRK is a one-laser procedure, using an ultraviolet excimer laser created from a high-voltage electron beam from a combined noble gas and halogen to remove superficial outer layers of the cornea before reshaping the tissue.
Combining the use of two lasers, LASIK starts by using an ultrafast, pulsing femtosecond laser to create a flap that exposes the eye’s inner framework, the stroma, before following with the excimer laser for the reshaping.
Post procedure, LASIK typically yields a quicker recovery of about one day, compared to three to five days for PRK, where patients deal with light sensitivity and discomfort due to the more invasive process of removing skin.
“The skin layer heals from the outside in, so the visual recovery is a little longer, and because there are nerve endings exposed, that’s why there is more discomfort and sensitivity than with LASIK,” says Dr. Robin Beran, a longtime practicing ophthalmologist of Columbus Lasik & Cataract Center.
If choosing between laser procedures, recovery time is one factor to consider, as well as eye metrics and activity level. For those with thin corneas or who partake in high-impact sports, PRK is often recommended for less risk of complications from creating a flap or the development of dry eye.
Another laser procedure between LASIK and PRK is small incision lenticule extraction (SMILE). Initially performed in 2006 and then FDA-approved in 2016, SMILE is a flap-less procedure like PRK and uses a femtosecond laser to remove a small section, a lenticule, of the cornea to improve the light refraction process.
Although it has a shorter recovery window than PRK – estimated at one to two days – and poses less risk of flap-related complications, SMILE comes with an additional cost and its offering can depend on the ophthalmologist.
Future developments
As LASIK and other laser procedures continue to improve, new elements such as 3D imaging and topography-guiding have provided alternative navigation methods which can be especially helpful for irregularly shaped eyes.
Columbus Lasik & Cataract Center
Other advancements include real-time eye-tracking and cyclotorsion control, which account for involuntary and subtle eye movements during the procedure to adjust the laser as needed in live time.
Artificial intelligence has also become part of the screening and treatment plan process, helping analyze the topography scans and biometric measurements of the eye as well as processing habits to provide a detailed guide for the laser, aiding with unique cases where patients may have eye scarring, aberration and irregularities.
New laser procedures are also on the horizon. Beran notes LIRIC – laser-induced refractive index change – is one to look out for in the next 10 years or so.
With LIRIC combined with use of the femtosecond laser, refractive correction can change how tissue bends the light and its characteristics. So far, the procedure seems not only reversible, but may also be able to correct the prescription of implanted contact lenses for cataracts and myopia.
According to Beran, a procedure such as LIRIC would make past cataract procedures, such as the Light Adjustable Lens (LAL), less impactful.
Jane Dimel is an assistant editor at CityScene Media Group. Feedback welcome at jdimel@cityscenemediagroup.com.
