Photorefractive Keratectomy Laser Eye Surgery
By Nicola Kennedy
Photorefractive keratectomy (PRK) is a laser eye surgery procedure that is carried out with the key intent to correct a patient's vision. PRK permanently changes the shape of the frontal corneal tissue using an excimer laser, which is a high-precision ultraviolet chemical laser. The outer layer of the cornea (epithelium) is removed, and then a small amount of the corneal tissue is burnt off using the laser. Such an ablation renders the desired shape to the cornea and allows for optimal refraction.
PRK is a technologically advanced surgical procedure. For instance, a computer system tracks the eye position around 4,000 times per second, redirecting laser pulses for precise ablation. As mentioned above, the epithelium is removed prior to ablation. This does not hamper the patient's vision, since the epithelium is a soft and regenerating layer, which is capable of completely replacing itself within a matter of days. However, the deeper layers, once burnt off, will remain that way because they possess limited regenerative capability. This theory is the cornerstone of the Photorefractive keratectomy surgical procedure.
PRK differs from LASIK in a way that the epithelium is removed in PRK and allowed to regenerate. On the other hand, LASIK does not involve epithelium removal. Instead it consists of cutting a flap in the cornea in order to make the desired incisions. Compared to LASIK, a patient who has undergone PRK experiences more pain and recovery is slow. However, both procedures are similar in the respect that they make use of a laser.
Photorefractive keratectomy is a viable procedure, but it does have possible complications. Apart from slow recovery and pain, the patient may experience glares and halos. As in any refractive surgery, there is a possibility of over- or under-correction. Eye surgeons typically perform PRK on one eye at a time, in order to gauge the results of the procedure and ensure its efficacy.
In a majority of cases, PRK has proven to be a safe and efficacious procedure to correct myopia. However, since the procedure is irreversible, it is recommended that the patient consults an eye doctor instead of jumping on a conclusion.