Photorefractive Keratectomy (PRK) is a laser eye surgery that corrects vision problems like nearsightedness, farsightedness, and astigmatism. It uses an excimer laser to precisely reshape the cornea, improving how light focuses on the retina. While PRK is generally effective in reducing or eliminating the need for glasses or contact lenses, vision can change over time. This may lead some to wonder if a second PRK procedure, often called an “enhancement” or “re-treatment,” is possible.
Why a Second Procedure Might Be Needed
Patients may seek a second PRK procedure due to the eye’s natural healing processes or initial outcomes. One common reason is regression, where the eye gradually returns to some of its original refractive error after the initial surgery. This can occur as the cornea heals and remodels, leading to a slight return of nearsightedness, farsightedness, or astigmatism.
Another factor is under-correction, meaning the first surgery did not fully correct the vision, leaving some residual refractive error. Less frequently, a patient’s prescription might change significantly years after the initial PRK due to natural aging, such as the onset of presbyopia, though PRK does not directly address this.
Determining Candidacy for Re-treatment
Evaluating candidacy for a second PRK procedure involves a thorough ophthalmologist assessment, focusing on several key factors. Corneal thickness is a primary consideration, as a second PRK requires sufficient remaining tissue to maintain the cornea’s structural integrity. Removing too much tissue can compromise stability.
The overall health and stability of the cornea are also important. The eye must be free from conditions like keratoconus, a progressive thinning disorder worsened by further tissue removal. The patient’s refractive error, or prescription, must have been stable for generally 1 to 2 years to ensure lasting correction. General eye health is assessed to rule out conditions like severe dry eyes, glaucoma, or cataracts, which could complicate surgery or recovery. Generally, 6 to 12 months after the first surgery is recommended for complete healing and stabilization before considering re-treatment.
Expected Results and Potential Risks
Expected Results
A second PRK procedure can often improve vision and achieve the desired refractive outcome. Many patients experience significant visual improvement, further reducing their dependence on glasses or contact lenses. However, achieving perfect 20/20 vision is not guaranteed for everyone.
Potential Risks
A re-treatment carries specific risks, some heightened or unique compared to a primary PRK procedure. The risk of dry eyes may increase, as the procedure can further affect corneal nerves. Corneal haze, a clouding of the cornea, is another concern, though modern techniques often incorporate medications like Mitomycin-C to reduce its incidence. Glare and halos, which are visual disturbances, might persist or worsen. There remains a possibility of over- or under-correction, meaning vision might not be precisely as desired. A rare but serious complication is corneal ectasia, a progressive thinning and bulging of the cornea, a significant concern if too much tissue is removed; healing after a second procedure can sometimes be slower or less predictable.
Other Vision Correction Options
For individuals not suitable for a second PRK or who prefer to explore alternatives, several other vision correction options exist. Prescription glasses and contact lenses are the simplest and most common non-surgical solutions for residual refractive error.
The Implantable Collamer Lens (ICL) is another surgical alternative, where a thin, flexible lens is permanently placed inside the eye, typically behind the iris and in front of the natural lens. This option is often considered for those with higher prescriptions or corneas too thin for further laser reshaping.
For older patients, particularly those experiencing presbyopia or early cataract formation, Refractive Lens Exchange (RLE) is an option. RLE involves replacing the eye’s natural lens with an artificial intraocular lens, similar to cataract surgery, which can correct various refractive errors and reduce the need for reading glasses.