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ICT – Intraoperative Corneal Topography for image registration purposes S.Schründer

ICT – Intraoperative Corneal Topography for image registration purposes S.Schründer. Model eye. 6mm optical zone. 8mm corneal radius. 6mm pupil, 4mm below apex. 5mm to rotation axis. 12mm radius bulbus. Tilted eye. Aberrometer. Eyetracker. Ablation pattern. Ablation pattern.

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ICT – Intraoperative Corneal Topography for image registration purposes S.Schründer

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  1. ICT – Intraoperative Corneal Topography for image registration purposes S.Schründer

  2. Model eye 6mm optical zone 8mm corneal radius 6mm pupil, 4mm below apex 5mm to rotation axis 12mm radius bulbus

  3. Tilted eye

  4. Aberrometer Eyetracker Ablation pattern Ablation pattern Tilted eye Tilted eye 1st wrong pattern 2nd wrong pattern Motivation Diagnosis Treatment

  5. Solution Registration in 3d space

  6. Requirement 3d objects

  7. Height map pre ablation* *Difference to 8.4mm sphere Range 100µm

  8. Height map post ablation* *Difference to 8.7mm sphere Range 100µm

  9. Fine registration: Iterative Closest Point Find corresponding 3d points (via Hough tables) Minimize their distance • Distance Minimization: • Levenberg-Marquardt • for fast convergence • Simmulated annealing • to overcome local minima

  10. Registration points area Detected flap edge

  11. Difference map after registration 7.5mm circle Range 105µm

  12. Line scans Dimensions in mm

  13. 3d Flap thickness 9.5mm circle Range 290µm

  14. Line scans Dimensions in mm

  15. Next steps Rigid incorporation into a laser system Extended clinical trials Stand alone device

  16. Centered cornea

  17. 0.5mm lateral shift

  18. Corresponding tilt 0.22mm decentration

  19. Linear function* *8mm corneal radius, 4mm apex/pupil, 13mm apex/rotation axis

  20. Coworkers at BioShape Andreas Dankert Hendrik Fuchs Saso Spasovski

  21. Thank you. bioshape.com

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