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In PRK, the epithelium (outer "skin" of the cornea) is manually removed and an excimer laser is applied to the exposed stroma underneath. The epithelium then grows back.
PRK was the first laser eye surgery to be commercialised. It never achieved the success that was expected for it, however. It was quickly overtaken by LASIK, which offered patients (and doctors) the irresistible attractions of a faster visual recovery and little discomfort during healing. LASIK was also offered for a much wider range of prescriptions.
PRK carries the risk of haze (scarring on the cornea), particularly with higher amounts of correction. However, this risk is mitigated today with techniques such as use of mytomycin C.
In many ways PRK is much safer than LASIK. There is no blade or flap involved, which eliminates many of the most serious LASIK complications. Additionally, PRK does not penetrate so deeply into the cornea, so there is far less risk of ectasia.
Industry pioneers are continuously seeking ways to refine PRK and reduce or eliminate the drawbacks which make it less attractive to patients. This gave rise to techniques such as LASEK and Epi-LASIK. |
