1. 21/09/04www.drmathys.be ESCRS 2004 PARIS Wavefront- and Topography- guided PRK for Myopic Eyes Bernard Mathys, MD Brussels Vision Clinic

2. 21/09/04www.drmathys.be ESCRS 2004 PARIS Zyoptix (B&L) for PRK 100 000 Procedures for Z – Lasik Orbscan and Aberrometry-guided ablation Tissue saving, wide optical zone, reduce treatment-induced aberrations Adapted for PRK – using the same preop measurements

3. 21/09/04www.drmathys.be ESCRS 2004 PARIS Why Zyoptix ? Thin cornea: < 520 µ Large pupil Tissue saving Aberrations preop > 0.30µ RMS PSF

4. 21/09/04www.drmathys.be ESCRS 2004 PARIS Technique Topography and aberrometry by the same well-trained technician Alignment under the laser, head position: crucial PRK: std technique Postop treatment: std

5. 21/09/04www.drmathys.be ESCRS 2004 PARIS Results

6. 21/09/04www.drmathys.be ESCRS 2004 PARIS Aberrations Measurements of all aberrations preoperatively Same postop: 1M, 3M, 6M, 12M Time development view Normal band view Orbscan

7. 21/09/04www.drmathys.be ESCRS 2004 PARIS Example 1: thin corneas

8. 21/09/04www.drmathys.be ESCRS 2004 PARIS Example 1: thin corneas

9. 21/09/04www.drmathys.be ESCRS 2004 PARIS Example 2: large pupil

10. 21/09/04www.drmathys.be ESCRS 2004 PARIS Example 2: large pupil

11. 21/09/04www.drmathys.be ESCRS 2004 PARIS Example 3: limited induced aberrations

12. 21/09/04www.drmathys.be ESCRS 2004 PARIS Contrast sensitivity

13. 21/09/04www.drmathys.be ESCRS 2004 PARIS RMS changes

14. 21/09/04www.drmathys.be ESCRS 2004 PARIS Discussion If thin cornea, PRK more suitable However, higher correction may induce more haze, delayed visual recovery, regression, etc… Our experience: exactly the same But Z-PRK: less haze, better astigmatic correction, wider optical zone, no contrast loss

15. 21/09/04www.drmathys.be ESCRS 2004 PARIS Conclusion Very interesting technique Need a correction factor for the aberrometer measurements (ours: 90%) Alignment crucial Cyclotorsion Corneal marking for astigmatism

16. 21/09/04www.drmathys.be ESCRS 2004 PARIS No higher RMS postop for high correction No higher RMS postop for large OZ Seems to reduce RMS for OZ 6 – 6.5 Safe and effective: no loss of VA

17. 21/09/04www.drmathys.be ESCRS 2004 PARIS Thank you for your attention