Since both PRK and LASIK employ excimer laser technology, patients that undergo these laser eye surgery procedures will face similar risks. The risks include overcorrection, under correction, regression, irregular healing (including decentration, corneal islands, and irregular astigmatism, with possible loss of best corrected spectacle visual acuity), glare, nighttime halos, with possible increased difficulty driving at night (especially if there are large pupils or a high level of astigmatism). The most common risk is overcorrection or undercorrection, which occurs when a refractive error develops or persists in the eye after it has healed.
Although laser correction can improve every patient's vision, there is a range for how much each patient responds to the procedure. For the most part, the results depend on the patient's prescription. Lower corrections, such as less than -6.00 diopters of myopia or +4.00 diopters of hyperopia, do very well, with over 99 percent achieving 20/40 or better vision (without glasses) with standard LASIK or PRK, and even better results with Wavefront-guided correction. Higher corrections, however, are less predictable. Both PRK and LASIK appear to give the same results for overcorrection and undercorrection, i. e. the predictability of the procedure. Contact the Beverly Hills LASIK Center if you would like to learn more about laser eye surgery, and live in or can travel to the Beverly Hills, Santa Monica, or the Los Angeles area.
If your vision is not as good as you expect it or want it to be, most patients can elect to have a retreatment or enhancement done to improve their vision. A small percentage of patients may experience some regression of the effect of their procedure and can usually undergo a retreatment.
Glare and halos, which are generally seen at night, are some examples of the unwanted optical side effects of laser eye surgery. These problems were much more common in the early years of laser vision correction, when less sophisticated lasers and smaller optical zones were used. Today, the current lasers have smoother treatments and larger treatment zones, making side effects like significant glare and halos less common. Patients with larger than average pupils in dim light or high levels of correction will be counseled about their relative risk for glare and halos. Wavefront-guided or wavefront optimized laser vision correction is often the best solution to lower the risk of glare and halos with the original treatment, and can often be used as a retreatment if needed to treat persistent glare and halo symptoms in those individuals that still develop the symptoms. Irregular astigmatism can rarely occur, resulting in a warped shape to the cornea. It can uncommonly lead to a decrease in best-corrected visual acuity, and may be corrected with wavefront-guided retreatment.
Infection is a risk that can occur with either PRK or LASIK, but PRK infections are more common, but also easier to treat than those from LASIK. The reason is that PRK infections develop on the surface of the eye, whereas a LASIK infection is generally located in the deeper section of the cornea - making it difficult to treat and more likely to scar. Studies show that LASIK infections occur in less than one in 1,000 cases. When choosing between the laser eye surgery PRK and LASIK, most of our Santa Monica and Los Angeles area patients elect LASIK if they have no additional problems with their eye, such as a thin cornea, an irregular cornea, a corneal scar, or have an occupation or sports, or an interest that places them at extra risk for eye injury.