PRK: PRK (Photorefractive Keratectomy) was the first corneal procedure upon which FDA approval was given for the first generation of FDA approved excimer lasers. PRK involves complete removal of the corneal epithelium (surface layer of the cornea) followed by application of the excimer laser to the exposed corneal surface. The epithelium regenerates over a period of 3-5 days. The visual outcomes between LASIK and PRK are virtually equivalent. LASIK is preferred however due to the quicker recovery.
The Advantage of PRK compared with iLASIK is that there is no flap and therefore no flap complications.
The Disadvantages of PRK compared with iLASIK: 1) Slow recovery of vision. PRK patients may not have legal driving vision for one week after the procedure, 2) retreatments also have a slower recovery process than iLASIK retreatments, 3) rare chance of corneal scarring, 4) mild/moderate irritation lasting 1-2 days.
Differences between PRK and LASIK
|Range of correction||Low to Moderately high||Low to Moderately high|
|Wound Depth||Superficial (remove epithelium)||20% depth (flap preserves epithelium)|
|Postoperative Pain||Moderate 24-48 hrs.||3 to 6 hrs.|
|Postoperative Medications||3 weeks to several months||1 to 2 weeks|
|Functional Vision Recovery||3 to 7 days||24 hours|
|Visual Results Fully Recognized||3 weeks to several months||1 to 6 weeks|
|Return to Work||2 to 3 days||1 to 2 days|
|Risk of Complications||Low||Low|
|Risk of Scarring||1 to 2%||<1%|
|Dry Eye Sensitive||1 to 4 weeks||Could last up to 12 months or more|
|Candidates with Thin Corneas or Wide Pupils||Often good candidates||Candidacy depends on amount of correction needed|