Until contact lenses were popularized in the 1950s, eyeglasses for at least the past seven centuries had been the only practical way to correct refractive vision errors.
Now, several modern approaches to corrective eye surgery range from laser reshaping of the eye's surface in procedures such as LASIK and PRK to surgical insertion of artificial lenses to correct eyesight.
In LASIK, PRK, and similar procedures, laser energy reshapes the curvature of the eye's clear front surface (cornea) to alter the way light rays enter the eye. Artificial lenses surgically inserted into the eye also can refocus light rays to sharpen vision.
The Evolution of Corrective Eye Surgery
Over the past 25 years, surgical techniques, tools, and procedures for vision correction have evolved rapidly.Radial Keratotomy (RK), used in the United States primarily during the 1980s, involved cutting spoke-like incisions to flatten the eye's surface mainly to correct nearsightedness.
But results, especially long-term, created problems for some individuals. Significant glare, regression, fluctuating vision, and other side effects such as night vision problems were common in patients who had RK for higher prescription strengths, while such side effects were less frequent in patients with lower prescriptions.
RK is now virtually obsolete as a primary vision correction procedure for these reasons and because of advances in laser vision correction procedures.
Photorefractive Keratectomy (PRK) was the first successful laser vision correction procedure used to remove (ablate
) tissue directly from the eye's surface to change the curvature of the cornea. PRK, also known as surface ablation, was performed outside the United States during the 1980s and received FDA
approval in 1995. PRK is still commonly used, but LASIK (see below) is by far the most popular laser procedure today.
However, PRK has made somewhat of a comeback in recent years because of studies indicating that PRK and LASIK produce similar outcomes. Also, nerve regeneration in the eye's surface appears to take place faster with PRK than with LASIK following a procedure, which could have implications for reducing dry eye and other complications that might occur until the healing process is complete.
Because PRK is a surface procedure, there also is no risk of surgical flap complications. PRK does not involve creating a thin, hinged flap on the eye's surface, as occurs with LASIK. PRK also appears to be a safer procedure in cases when a person's cornea may be too thin for LASIK surgery.
Recent technological advances have given eye surgeons better methods of creating thinner flaps in a predictable way, meaning that people with thin corneas now might be candidates for a LASIK procedure.
However, you probably should consider a different type of vision correction procedure if you have a thin cornea and high degree of myopia that would require extra ablation to reshape the eye.
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