Termed as Advanced Surface Ablation, PRK (Photorefractive Keratectomy) is a vision correction procedure that is an alternative to conventional LASIK. While LASIK is the more common procedure, it is not always the most suitable treatment for everyone. PRK is “flap-free” and can deliver the same laser vision correction as LASIK without the need to cut a cornea flap.
During PRK, the eye’s front-most layer of cells, called the corneal epithelium, is removed and an excimer laser is then used to reshape the cornea to produce the desired correction.
Are You A Suitable Candidate for PRK?
- You have thin corneas
- Your lifestyle or job puts you at a risk of eye trauma
- You participate regularly in contact or extreme sports such as soccer, rugby and martial arts
- You work in dynamic environments like the military
- For PRK: Your myopia or hyperopia is less than -5.00 dioptres and the astigmatism is not more than -2.5D
As with all laser vision corrections, you should:
- be at least 18 years of age
- have stable eye prescription for at least a year
- not have any eye problems such as cataract or glaucoma
- not be pregnant or breastfeeding
The PRK Procedure
Step 1: The procedure begins with anaesthetic eye drops to numb the eye, then an alcohol solution is used to dissolve the corneal epithelium, which is then removed with a special instrument.
Step 2: The pre-programmed excimer laser then ablates the corneal tissue. This reshapes the curvature of the cornea to correct the refractive error.
Step 3: A bandage contact lens is then used to cover the treated cornea to assist the healing process.
The Epi-LASIK Procedure
Epi-LASIK is a new variant of PRK, which uses a mechanical, blunt tissue separator instead of alcohol solution to separate the epithelium. This avoids the possible risk of a reaction from the alcohol and results in faster healing. The same laser used in LASIK and PRK is applied and this thin layer of cells is then placed back over the cornea. This procedure is suitable for those with thin corneas but require a high degree of correction.
Advantages of PRK
- No risk of cornea flap complications
Unlike conventional LASIK, the procedure avoids the creation of a cornea flap, thereby avoiding risks of cornea flap dislodgement, wrinkles or infection. It is hence a safer choice for people with very active lifestyle or whose jobs subject them to higher risks of eye injury.
- Structural integrity of the cornea is maintained
As the procedure requires less corneal tissue removal, it is a suitable treatment for people with high myopia or thin corneas. There is reduced risk of postoperative corneal ectasia, a rare condition where the thin cornea bulges forward and distorts the vision.
- The long-term visual outcomes and success rates are almost identical to LASIK
Concerns Regarding PRK
- It typically involves more discomfort and a longer recovery time than conventional LASIK.
- It can take several weeks before the optimum visual acuity is achieved.