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:
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Complications associated with making the flap are virtually eliminated thus enhancing patient safety.
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Final visual acuities in eyes treated with intralase are more accurate than any LASIK (blade-flap) procedure.
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Fewer visual aberrations (halo, glare, starburst) are created in iLASIK. Therefore quality of vision in iLASIK should be clearer than with standard LASIK.
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Patients with thin corneas not suitable for standard LASIK can be treated safely with iLASIK due to the ability to create an accurate thin flap via computer-controlled delivery of the laser.
Differences between PRK and LASIK
PRK |
LASIK |
|
|---|---|---|
|
Range of correction |
Low to Moderately high |
Low to Moderately high |
|
Wound Depth |
Superficial (remove epithelium) |
20% depth (flap preserves epithelium) |
|
Intraoperative Pain |
None |
None |
|
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 |
