The document discusses optical modeling profiles used in refractive surgery planning. It describes how traditional profiles like WFO, F-CAT, and T-CAT do not consider individual eye optics and rely on averaged data. A new virtual eye model is presented that uses diagnostic data from tools like oculyzer, wavefront analyzer, and biometry to create a personalized eye model for each patient. Ray tracing is used to simulate refractive corrections and optimize ablation profiles. A clinical study showed the individualized ray tracing approach provided better refractive predictability compared to wavefront optimized treatments.

1. Optical Modeling Profile in Refractive surgery Michael Mrochen, PhD IROC AG Institut für Refraktive und Ophthalmo-Chirurgie Stockerstrasse 37 8002 Zürich WWW.IROC.CH

2. Ablation profiles WFO: not based on individual optics Considers “averaged eyes”, no higher order aberrations F-CAT: Based on “theoretical” corneal shape No higher order aberrations WFG: does not consider geometrical shapes and distances of corneal and lens Refractive corrections can induces additional aberrations T-CAT: Based on corneal front surface No internal optics, refractive predictability is limited

3. Optical Modeling Profile in Refractive surgery Virtual eye model based on patient specific data from multiple diagnostic tools for planning refractive surgery procedures.

4. Diagnostic data of an individual eye are used to create a virtual eye model

5. Oculyzer The oculyzer measures the anterior and posterior shape of the cornea. Height information includes corneal curvatures, asphericities, and astigmatism as well as irregular components Height data are imported to the planning software.

6. Wavefront Analyzer Wavefront aberrations are measured by ray tracing the eye Sphere, cylinder and higher order aberrations are measured. Wavefront data are imported to the planning software. Camera Laser Mask out-going optics in-going optics

7. OB820 CCT, ACD, lens thickness, eye length are measured. Biometric data are imported to the planning software.

8. Diagnostic data of an individual eye are used to create a virtual eye model

9. Thin lens optics Marginal ray Chief ray Object Image Focal length Pupil

10. Thin lens optics Objective Ocular Object Focal length Focal length Image

11. One refractive surface Air n = 1 Cornea n = 1.376 Radius of curvature R = 7.78 mm     Snell’s law Ray height Ray height Thickness of the surface New Ray Heights

12. Two refractive surfaces     Thickness 1 Thickness 2 Refractive index n=1.5 Refractive index n=1.0 Refractive index n=1.0 Radius of curvature R1 Radius of curvature R2

13. Example fish eye lens

14. Optical ray tracing Calculating the path of light through an optical system with regions of different thicknesses and refractive indices Ray tracing solves the problem by applying idealized narrow light beams called “rays” through discrete media. Even very complex optical systems can be calculated by using a computer to propagate many rays.

15. Ray tracing the human eye CCT ACD LT PCD n c n ACD n L n PC R CF ,Q CF R CB ,Q CB R LF ,Q LF R LB ,Q LB

16. IOL power calculation

17. IOL position

18. Corneal laser surgery

19. Optical Modeling Profile in Refractive surgery Create an individual eye model Software finds the best possible ablation profile All available individual diagnostic data are used. A test treatment is simulated before it is transferred to the excimer laser

20. Clinical study Prospective clinical trail at 3 sites (Seiler, Maus,Cummings) 135 eyes included 3 months follow up. Patients were treated either with Ray tracing + corneal modeling Enhanced T-CAT + corneal modeling

21. Clinical study Inclusion criteria: MRSE > -4.0 or Cyl > 2.0D Primary outcome measures @ 3 months: Safety Efficacy Refractive predictability Secondary outcome measure Topography Wavefront data

22. Results of the investigator sites: Maus, Seiler and Cummings Refractive predictability significant better than with wavefront optimized treatments (88% within ±0.5D of MRSE) Efficacy equal to other treatment (87% with 20/20 UCVA after surgery out of 93% of 20/20 BSCVA before surgery Safety equal to other treatments (1% with loss of 2 lines) 78% unchanged or gained 1 or more lines in BSCVA

24. Clinical benefits demonstrated (today) Better refractive predictability in high myopic eyes One profile fit’s all High flexibility in personal nomograms Wavefront recommended Less tissue removal compared to T-CAT and A-CAT Easy to explain to patients (talk to Arthur)

25. Thank you