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Effect of CXL on FS laser Channel Creation for ICR in KC
Tamer M. El-Raggal, MD, PhD, FRCSEd Associate Professor of Ophthalmology Ain Shams University, Cairo - Egypt
No Financial Interest
1. Studies demonstrated efficacy of ICRS → improvement of KC.
2. CXL ↑ mechanical stiffness → stabilization of KC
3. FS laser photodisruption → separate tissue at molecular level without impact on surrounding tissue.
• Combination of 3 modalities provide better results as they complement each other.
Introduction
El-Raggal, T
Aim of the Study
• To evaluate efficacy of FS laser for channel creation after CXL in KC eyes.
Inclusion criteria• CL intolerance.• Clear cornea. • Maximum K < 60 D.• Minimum thickness > 450 µm.• CXL done 6 m before.
El-Raggal, T
Patients & Methods
• A prospective non-randomized study included 15 eyes of 11 patients with II-III KC (Amsler- Krumeich) treated by CXL → 6 m later channel creation using Intralase FS 60.
• Group 1 5 eyes → 1.50 mJ• Group 2 5 eyes → 1.60 mJ• Group 3 5 eyes → 1.70 mJ
• Control 5 virgin KC eyes → 1.50 mJ
El-Raggal, T
• Axis → steep topography.• 80% depth.
• Inner diameter 5.0 & outer 5.8 mm. • Entry cut thickness 1 µm.• Incision length 1.40 mm.
• Ring energy 1.50 – 1.70 mJ.• Spot separation Default.• Implantation immediately before
bubbles disappear using forceps.
Corneal Channels CreationCorneal Channels Creation
El-Raggal, T
Keraring InsertionKeraring Insertion
• ICR insertion graded subjectively0 = Easy, no resistance1+ = Slight resistance2+ = Moderate resistance, some manual separation3+ = Difficult, severe resistance, all manual dissection
• Corneal haze quantified subjectively on slit lamp 0 = No haze, totally transparent1+ = Slight corneal haze, slight loss of transparency2+ = Moderate haze. iris details seen3+ = Exaggerated haze, iris details hardly seen
El-Raggal, T
0
1
2
3
4
5
1.5 mJ 1.6 mJ 1.7 mJ Control
0 1 + 2 + 3 +
Results
Difficulty
El-Raggal, T
0
1
2
3
4
5
1.5 mJ 1.6 mJ 1.7 mJ Control
0 1 + 2 + 3 +
Results
Haze
El-Raggal, T
• Incomplete tunnel creation is most common difficulty of FS laser
• Tissue bridges in tunnel may resist ICRS implantation.
• Although channel creation & segment implantation can be done without changing FS parameters, it is better to ↑ energy.
• Resultant ↑ corneal reaction postoperatively.
El-Raggal, T
• CXL causes compactness of stromal lamellae in superficial 300 µm but deeper stroma also affected to some extent
• Also CXL cornea less clear than normal → FS laser penetration less effective.
Conclusion
El-Raggal, T
Conclusion
• FS channel creation can be performed safely after CXL.
• Better to perform channel dissection before or concurrent to CXL → More improvement in corneal shape by ICR.
• Limitations: Non-randomized, small sample, subjective grading of difficulty & haze.
• Further studies with larger samples & studying effect of spot separation recommended.
El-Raggal, T
THANK YOU
