This presentation try to answer the recent debatable question about which is better LASIK or PRK , when to choose each of them and how to exclude complications of both procedures.
6. First: Why doctors return to PRK again ?
Easy technique
No flap related complications
Less ectasia
Less cost
7. 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
8. 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
10. 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
11. PRK is not a completely safe technique, it has
its own problems.
12. Problems of PRK
1. Haze:
• Early: Due to early removal of therapeutic
contact lens (bad healing)
• Late: Subepithelial fibroblasts proliferation:
• UVA exposure
• High correction
21. 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
22. 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.
24. 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).
25. 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
26. 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)
27.
28. 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.