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Wavefront- and Topography-guided PRK for Myopic Eyes. Bernard Mathys, MD Brussels Vision Clinic. 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
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Wavefront- and Topography-guided PRK for Myopic Eyes Bernard Mathys, MD Brussels Vision Clinic www.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 www.drmathys.be ESCRS 2004 PARIS
Why Zyoptix ? • Thin cornea: < 520 µ • Large pupil • Tissue saving • Aberrations preop > 0.30µ RMS • PSF www.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 www.drmathys.be ESCRS 2004 PARIS
Results www.drmathys.be ESCRS 2004 PARIS
Aberrations • Measurements of all aberrations preoperatively • Same postop: 1M, 3M, 6M, 12M • Time development view • Normal band view • Orbscan www.drmathys.be ESCRS 2004 PARIS
Example 1: thin corneas www.drmathys.be ESCRS 2004 PARIS
Example 1: thin corneas www.drmathys.be ESCRS 2004 PARIS
Example 2: large pupil www.drmathys.be ESCRS 2004 PARIS
Example 2: large pupil www.drmathys.be ESCRS 2004 PARIS
Example 3: limited induced aberrations www.drmathys.be ESCRS 2004 PARIS
Contrast sensitivity www.drmathys.be ESCRS 2004 PARIS
RMS changes www.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 www.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 www.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 www.drmathys.be ESCRS 2004 PARIS
Thank you for your attention www.drmathys.be ESCRS 2004 PARIS