PRK ….Is it a good alternative to LASIK ?

Dr. Amr Mounir.MDLecturer of OphthalmologySohag University Hospital

By

To answer the title question we should ask ourselves another group of questions

First: Why doctors return to PRK again ?

PRK

LASIK

Second: Is LASIK a hazardous technique ?

Third: What are benefits of PRK over LASIK ?

LASIK

PRK

First: Why doctors return to PRK again ?

Easy technique

No flap related complications

Less ectasia

Less cost

Second: Is LASIK a hazardous technique ?

Hazardous in the following conditions

1. Long-term safety

2. Flap related complications

3. Suction high pressure effect on posterior

segment

Third: What are the benefits of PRK over LASIK?

More safe → No flap → No damaging effect in

corneal architecture → Maintained corneal

stability → Less ectasia

Less thinning → More residual bed

Can be done for suspicious corneas

No effect on posterior segment

No dry eye

Economic AspectNo Blade

However, after answering the previous questions

The last question is:• Why great evolution had occurred from PRK

to LASIK in the beginning of excimer laser corneal refractive surgeries

PRK is not a completely safe technique, it has its own problems.

Problems of PRK1. Haze:• Early: Due to early removal of therapeutic

contact lens (bad healing)• Late: Subepithelial fibroblasts proliferation:• UVA exposure• High correction

PRK haze

Problems of PRK

2. Epithelial healing problems:• Persistent defect • Infection

3. Regression in refraction4. Slow rehabilitation5. Scar formation

POST.PRK infection

Post.PRK Scar

Benefits of LASIK

1. Time honored procedure2. Stable refraction3. Rapid rehabilitation 4. No haze5. No epithelial healing problems

How can we increase LASIK safety ?

By creating ultrathin flaps by:1. Sub bowman’s keratomileusis (SBK)2. Femtocreated flaps

Indications of PRK

• Thin cornea • Suspicious cornea• In combination with corneal collagen CXL

in keratoconic eyes (Athens protocol)

Advanced Surface Ablation

Cataract & Refractive Surgery Today EUROPE May 2013

Advanced Surface Ablation

1. LASEK, in which the epithelium is removed with alcohol

2. Epi-LASIK, in which the epithelium is mechanically lifted without adjunctive agents.

In both procedures, laser photoablation is performed just above the Bowman layer

Advantages 1. Done in high myopes (–6.00 to –10.00 D).2. Avoids all the flap-related complications

seen in LASIK, including incomplete flaps, free caps, buttonhole flaps, flap striae, dislocated flaps, flap melts, epithelial ingrowth, and DLK.

3. Safety in posterior segment.

Improvement of PRK quality of vision

How to avoid haze in advanced ablation ?

1. Preoperative : Ask thoroughly about healing of wounds in body as general ( over healing e.g: skin Keloids).

How to avoid haze in advanced ablation ?

2. Intraoperative : - Mitomycin C application (0.02%). - Washing the bed with cold BSS every 3 Ds to lessen the thermal effect of laser ablation

How to avoid haze in advanced ablation ?

3. Postoperative : - Avoid early removal of contact lens before complete epithelial healing.(early onset haze)- Long term topical steroids therapy .(late onset haze)- Avoid sunrays exposure.( Late onset haze)

PRK is a good alternative to LASIK as regard safety and corneal stability, however it carries some problems especially haze and epithelial healing problems.

LASIK is better in straight forward cases especially with ultrathin flaps.

Thank you