This document discusses different types of refractive surgery, including surface ablation techniques like PRK as well as LASIK. It notes that while LASIK became popular initially due to faster recovery times, surface ablation procedures have advantages in safety and corneal stability since they do not create a flap. The document outlines some risks of LASIK like flap complications and long term safety issues. It also discusses problems with early surface ablation like haze and healing issues. More advanced surface ablation techniques like LASEK and Epi-LASIK are highlighted as safer alternatives to LASIK that avoid flap risks. The use of femtosecond lasers to create thinner, more precise flaps for LASIK is also discussed as a way to increase its safety profile.

1. BY
Dr. Amr Mounir
Assistant Professor of Ophthalmology
Sohag University, Egypt
Refractive surgery for
beginners : which surgery
for which patient

3. First: Why doctors return to Surface Ablation
again ?

4. Second: Is LASIK hazardous technique ?

5. Third: What are advantages of Surface ablation over LASIK ?

6. First: Why doctors return again to Surface
ablation?
Easy technique
No flap related complications
Less liability for future ectasia
Less cost

7. Second: Is LASIK hazardous technique ?
Hazardous in the following conditions
1. Long-term safety (in border line corneas)
2. Flap related complications
3. Suction high pressure effect on posterior segment

8. Third: What are the advantages of Surface
ablation over LASIK?
 More safe → No flap → No damaging effect in
corneal architecture → Maintained corneal
stability → Less liability for ectasia
Less thinning → More residual bed
 Can be done for border line corneas
No effect on posterior segment
less dry eye

9. Economic Aspect

10. No Blade

11. However, after answering the previous
questions
The last question is:
• Why great evolution had occurred from
surface ablation to LASIK in the beginning of
excimer laser corneal refractive surgeries

12. Surface ablation is not a completely safe
technique, it has its own problems.

13. Problems of Surface ablation
1. Haze:
• Early: Due to early removal of therapeutic
contact lens (bad healing)
• Late: Subepithelial fibroblasts proliferation:
• UVA exposure
• High error correction

14. Surface ablation haze

15. Problems of surface ablation
2. Epithelial healing problems:
• Persistent defect
• Infection
3. Regression in refraction
4. Slow rehabilitation

16. POST. Surface ablation infection

17. Post. Surface ablation Scar

18. advantages s of LASIK
1. Time honored procedure
2. Stable refraction
3. Rapid rehabilitation
4. No haze
5. No epithelial healing problems

19. How can we increase LASIK safety ?
By creating ultrathin flaps by:
1. Sub bowman’s keratomileusis (SBK)
2. Femtosecond laser
created flaps

20. Indications of PRK
• Thin cornea
• Suspicious cornea
• In combination with corneal collagen CXL in keratoconic
eyes (Athens protocol)

21. Advanced Surface Ablation

22. Advanced Surface Ablation
Cataract & Refractive Surgery Today EUROPE May 2013

23. 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

24. 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.

25. Improvement of PRK quality of vision

27. Surface ablation 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.

29. Femtosecond laser in ophthalmology
Uses:
•Femtolasik
•Femtosecond cataract surgery
•Femtokeratoplasty
•Femtosecond laser in
keratoconus

30. Patterns of femtosecond laser ablation

31. Flap Separation

32. Advantages: Optimal safety

33. Advantages:
Optimal safety
No flap related complications e.g.: free cap, button
holes, incomplete cuts
- Thinner flap:
Uniform thin flaps with no liability of complications
Thin flaps leads to large stromal bed with less liability
for ectasia
- Precise depth

34. Advantages: Flap Design

35. Advantages:
Flap Design
Large flap diameter : in HMT, in custom
ablation
Hinge : superior or nasal if there is cylinder
Hinge angle can be also modified

37. Flap shape
Femtosecond laser
Flap:
Planner Flap → less
complications → Less
Dry Eye
M2 flap : Meniscus flap

38. Flap edge
Flap edge :
Femtosecond laser can create
a corneal flap that has edges
that enable the flap to fit
more securely in place,
(inverted Side cut) > 90
degree “ beveled edge”
Better Biomechanics
M2 flap : 40: 70 degree

39. Advantages: less IOP elevation

40. Advantages:
less IOP elevation
•Femtosuction elevates IOP to about 18:25
mm.Hg
•Suction ring in conventional Lasik elevates
IOP to about 70: 80 mm.Hg
•Better in High myopia

43. When to do
Femto Lasik
?????

44. Indications:
1- Normal steep cornea : No risk of
button hole

45. Indications:
2. Flat cornea: No risk of free cap

46. Indications:
3- High Myopia :
- Controlled depth 90 um (Precise
depth)
- Less effect in the posterior segment

47. When large flap
diameter is needed :
in HMT,
in custom ablation