1. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Corneal Biomechanical Assessment using Dynamic Ultra High-Speed Scheimpflug Technology Non-Contact Tonometry (UHS-ST NCT): Preliminary Results Renato Ambrósio Jr., MD, PhD* Diogo L. Caldas, MD Isaac C. Ramos, MD Rodrigo T. Santos, MD Leonardo N. Pimentel, MD Cynthia Roberts, PhD* Michael W. Belin, MD* Dr. Ambrósio & Dr. Belin are consultants for Oculus Optikgeräte GmbH (Wetzlar, Germany) and have received research funding and travel reimbursements

2. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Introduction: Evolution on Corneal Propedeutics “Propedeutics” refers (in Medicine) to the collection of data about a patient by observations and examinations. Advances are recognized on the ability for architecture or goemetrical characterization of the cornea Keratometry, Keratoscopy, Videokeratography, Corneal Topography, Corneal Tomography

3. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Corneal Biomechanics: Relevance From Geometrical and Optical understanding, the next step is biological evaluation: healing response and biomechanics Ectasia mysteries* in Refractive Surgery had highlight the need for corneal biomechanical understanding (*ie: cases with no risk factors that develop ectasia after LASIK) Also to Customize Refractive Corneal Treatments; correctly measure IOP (intraocular pressure) and to possibly predict glaucoma risk Corneal biomechanical evaluations were limited to in vitro studies and to mathematical finite element models until the Ocular Response Analyzer (ORA-Reichert, Depew) in 2005 New techniques are under development for evaluating biomechanics This e-Poster presents a new system – The Corvis ST (Oculus, Wetzlar, Germany) with preliminary clinical results.

4. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Ultra High-Speed (UHS ST) Scheimpflug Technology takes 4,330 frames/sec with 8mm horizontal coverage Monitors corneal deformation response to a symmetrically metered air pulse The Oculus Corvis ST 1. Natural; (Ingoing Phase) 2. First Applanation (1st A) Momentum; 3 and 4. Ingoing Concavity Phase; 5. Highest Concavity Momentum; 6. Oscillation Period; (Outgoing Phase); 7. Second Applanation (2nd A) Momentum; 8. After Second Applanation; 9. Natural Back 1 st Applanation, Highest Concavity and 2 nd Applanation: Time and Length; Maximum Deformation; Maximum Velocity In and Out; Thickness

5. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Corvis ST: First Studies Experiment involving contact lenses mounted on an artifical pressurized chamber (Caldas et al., ePoster ASCRS 2011) found that the deformation response is influenced by lens properties and chamber pressure. (see video* PosterASCRS2011_clip_RAmbrosio). The inspection of the actual deformation process details corneal characterization, which has a potential for distinguishing normal (A, B) and keratoconus (C, D) corneas (see video* PosterASCRS2011_clip_RAmbrosio). Natural and Highest Deformation Momentum in a Normal (A, B) and a Keratoconic (C, D) Cornea

6. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Corvis ST: Clinical Parameters IOP: is the NCT measurement based on the 1 st Applanation 1st A-time: is the time from starting until the first applanation HC-time: time from starting until Highest Concavity is reached 2nd A-time: time from starting until the second applanation 1st A length: cord length of the first applanation 2nd A length: cord length of the second applanation Def Amp: maximum amplitude at the apex (highest concavity) W-Dist: distance of the two “knee’s” at highest concavity (HC) Curvature Rad HC: central concave curvature at HC Curvature Rad normal: initial central convex curvature Vin: corneal speed during the first applanation moment Vout: corneal speed during the second applanation moment

7. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group The Corvis ST was utilized to assess corneal deformation response in one eye from 71 keratoconic patients and in one eye from 178 normal patients. Clinical diagnosis was based on the complete eye exam, Placido- disk based corneal topography and Pentacam Corneal Tomography. Clinical Study Wilcoon Rank Sum (Mann- Whitney Test) IOP:< 0.0001 1st A Time:< 0.0001 2nd A Time:0.0006 1st A Length(max):0.0037 2nd A Length(max):0.0008 Curv. Rad. Normal:0.4126 Curv. Rad. HC:< 0.0001 Pachy Apex:< 0.0001 W-Dist.:0.0191 Def.Amp.(max):< 0.0001 Vin:< 0.0001 Vout:0.0001 Statistically significant distributions for all parameters (Mann- Whitney, p<0.05), but with significant overlap and AUC (area under the ROC curves) between 0.673 and 0.852

8. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Corvis Combo1: combined parameter Joint work with “Instituto de Computação” at UFAL (Universidade Federal de Alagoas*) to develop a combined parameter (Corvis Combo1) based on a linear regression analysis, considering the effects of IOP on deformation response parameters 0.033 * IOP - 0.004 * Pachy Apex - 0.448 * 1st A Time - 0.049 * HC Time + 0.093 * 2nd A Time + 0.026 * 1st A Length(max) - 0.105 * 2nd A Length(max) + 0.208 * Def Amp (max) - 0.619 * W-Dist - 0.021 * Curv, Rad, HC - 0.101 * Curv, Rad, Normal - 0.525 * Vin - 0.166 * Vout + 7.952 NKC Ave-0,008010,506829 SD0,2183480,26691 * Prof. Aydano P. Machado & J. M. Lyra, MD, PhD

9. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group AUCSE a95% CI b 1st_A_Time_ 0,8020,03130,747 to 0,850 Def_Amp__max__0,7490,03550,691 to 0,802 Pachy_Apex_0,8520,02650,801 to 0,893 Curv__Rad__HC_0,8520,02900,802 to 0,894 Curv__Rad__Normal_0,8100,03290,755 to 0,857 CorvisST Combo10,9310,01910,892 to 0,959 a DeLong et al., 1988 b Binomial exact The Corvis ST Combo1 performed statistically better (p<0.05; Pairwise ROC comparisons) than the individual parameters from the Corvis ST to distinguish 71 keratoconic eyes and 178 normal eyes (one eye per patient included) This approach has been complementary to enhance the diagnosis of ectasia susceptibility. Clinical Study

10. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group There were very significant correlations (Spearman, p<0.001) between IOP and 1 st Applanation Time (rho=0.94), 2 nd Applanation Time (rho=-0.73), Deformation Amplitude (rho=-0.80), W-Dist (rho=-0.66), Curv Rad HC (rho=0.45), Vin (rho=-0.49), Vout (0.38) and Combo1 (rho=-0.44) There were significant correlations (Spearman, p<0.01) between Pachymetry at the Apex and IOP (rho=0.37), 1 st Applanation Time (rho=0.4) and Lengh (rho=-0.18 ), W-Dist (rho=-0.25), Curv Rad HC (rho=0.48), Vout (rho=0.3), and Combo1 (rho=-0.64) There was a positive correlation between age and HC Time (Spearman, p=0.0039; rho=0.22) Clinical Correlations

11. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Enhanced Screening for Ectasia Susceptibility Biomechanical data from Corvis ST enhances the capability to detect very mild cases of ectasia and also help to characterize stable cases with asymmetric bow tie and inferior steepening (ABT/IS). Biomechanical data from Corvis ST enhances the capability to detect very mild cases of ectasia and also help to characterize stable cases with asymmetric bow tie and inferior steepening (ABT/IS). 26 eyes diagnosed as Forme Fruste Keratoconus (FFKC), with normal front curvature map while the fellow eye has keratoconus were examined. 26 eyes diagnosed as Forme Fruste Keratoconus (FFKC), with normal front curvature map while the fellow eye has keratoconus were examined. 25 eyes with ABT/IS but with no other clinical or tomographic sign of ectasia were examined. 25 eyes with ABT/IS but with no other clinical or tomographic sign of ectasia were examined. Combo1 24/178 (13%) normal eyes >0.21 9/71 (13%) keratoconic eyes <0.21 21/26 (80%) eyes with FFKC >0.21 8/25 (32%) ABT/IS cases >0.21 Kruskall-Wallis Test NormalKCFFKCABT/IS Normal <0.05 NS KC NS<0.05 FFKC <0.05 NFFK1KCABT Ave-0,008010,3455290,5068290,133745 SD0,2183480,1960430,266910,181624 171267125 see video* PosterASCRS2011_clip_RAmbrosio

12. © R. Ambrósio Jr, MD, PhD - 2011 R. Ambrósio Jr & Rio de Janeiro Corneal Tomography and Biomechanics Study Group Combo 1=0.16 Combo 1=0.31 The inspection of corneal deformation during NCT enables biomechanical characterization The deformation is severely influenced by IOP Combo1 from Corvis ST provides clinically relevant parameter to enhance sensitivity and specificity to detect ectasia. Corvis ST: Conclusions ABT with no Ectasia (A,B) x FFKC (C, D) This approach is complementary to Corneal Tomography with the Pentacam for screening refractive candidates