Ambrósio et al e-POSTER Enhanced Screening for Refractive Candidates based on Corneal Tomography and Biomechanics Renato Ambrósio Jr., MD, PhD Ruiz Alonso, MD; Daniela Jardim, MD; Frederico xxx, MD Marcella Salomão, MD; Simone Boghossian, MD; Bruno Fontes, MD Rio de Janeiro - Brazil

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Screening Refractive Candidates Ultrasonic Pachymetry (US-CCT) and Placido Corneal Topography have been considered the “gold standard” Unexplained ectasia may occur in cases considered as good candidates based on CCT and Placido´s topography Enhanced screening with corneal tomography and biomechanics provides more sensitivity and specificity for determining candidacy for LASIK

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Clinical Example 1: LASIK Candidate? 32 years old, female 32 years old, female MRx OD: = x 180º, 20/15 US-CCT: 528 µm Clinical Example 2: LASIK Candidate? 21 years old, male 21 years old, male MRx OS: -1,00 - 0,50 x 126, 20/15 US- CCT: 531 µm

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Example 1: “unexplained” ectasia after LASIK OS Example 2: “unilateral” keratoconus OD

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Screening Refractive Candidates US-CCT and Placido Corneal Topography would qualify cases 1 (OD) and 2 (OS) for LASIK Case 1 had similar condition in OD when presented for LASIK, which resulted in “unexplained” ectasia Either cases would not be considered as a good candidates for LASIK if considering topography from the contra-lateral eye But a bilateral presentation as in the “normal” eyes may be the reason for many cases with ectasia after LASIK with no identifiable risk factors Purpose: To present novel criteria based on corneal tomography (CTm) and biomechanical measurements to screen for ectasia (and for ectasia susceptibility)

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Ectasia Susceptibility: Conreal Tomography and Biomechanics Example 1: “unexplained” ectasia after LASIK OS Example 2: “unilateral” keratoconus OD CTSP and PIT: Abnormal S shape CTSP and PIT: Abnormal S shape CRF: 8.1 mmHg CRF: 8.1 mmHg CTSP and PIT: Tangent to 95% CI CTSP and PIT: Tangent to 95% CI Ave PI=1.2 Ave PI=1.2 CRF: 7.1 mmHg CRF: 7.1 mmHg

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Corneal Tomography: Corneal Thickness Profiles Average of the thickness values along twenty-two imaginary circles centered on the thinnest point TP with increased diameters at 0,4mm-steps - CTSP Average of the thickness values along twenty-two imaginary circles centered on the thinnest point TP with increased diameters at 0,4mm-steps - CTSP PTI - Percentage of increase from the thinnest point of each of the circles x - TP) / TP Data is presented in a Graph with 95%CI from a normal population Data is presented in a Graph with 95%CI from a normal population Progression Index: average, min and max Thinnest Point Value, Position and Distance from the Apex Thinnest Point Value, Position and Distance from the Apex

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Corneal Tomography: Enhanced Elevation (Belin) New reference sphere (new-BFS) that best fits to the peripheral corneal area excluding the central area with 4mm in diameter centered on the thinnest point New reference sphere (new-BFS) that best fits to the peripheral corneal area excluding the central area with 4mm in diameter centered on the thinnest point The elevation map considering the new-BFS was subtracted from the elevation map with the standard BFS that best fits the total corneal area. The highest difference between the elevation maps in the central 4mm area was noted for anterior and posterior cornea Anterior - green is below 6 yellow is between , red is > 12 Posterior: green is 20 New-BFS enhances the cone Standard-BFS may “hide” the cone

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Belin-Ambrósio Enhanced Ectasia Display Enhanced Elevation and Pachymetric Profiles are complementary to increase sensitivity and specificity! Enhanced Elevation and Pachymetric Profiles are complementary to increase sensitivity and specificity!

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Asymmetric Keratoconus Study Patients with keratoconus in one eye and normal axial (surface) topography in the contra-lateral eye were collected from different centers All cases: 25 patients (20 ♂) had Pentacam exam 12 patients (8 ♂) had additional biomechanical measureemnts (ORA - Reichert) Average age: 30.2 (From 16 to 58) 88% had at least one abnormal finding on the Belin/Ambrósio Enhanced Ectasia] CRF (ORA) was lower than 8.5 mmHg in 84% of cases Hysteresis (ORA) was lower than 8.8 mmHg in 75% of cases Newer metrics from the ORA are under study

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Enhanced Elevation and Pachy Profiles are Complementary Combination of Enhanced Elevation and Pachymetric Profiles add to each other in sensitivity and specificity Combination of Enhanced Elevation and Pachymetric Profiles add to each other in sensitivity and specificity

Ambrósio et al e-POSTER Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Rio de Janeiro CornealTomograhyandBiomechanics Study Group Study Group Conclusions: Enhanced Screening for Refractive Candidates New diagnostic parameters based on Corneal Tomography (Enhanced Elevation and Pachy Profiles) and Corneal Biomechanics (Hysteresis, CRF and new metrics from ORA signals) add to Ultrasonic Pachymetry (US-CCT) and Placido Corneal Topography to enhance screening for refractive candidates These new parameters increase sensitivity and specificity for the screening process and should be considered