Carlos G. Arce MD, Paulo Schor MD, Mauro Campos MD

1. Traffic Light Color Distribution for Custom Color Scales: Application to Elevation, Curvature, Power, and Thickness Maps Ocular Bioengineering and Refractive Surgery Sectors, Institute of Vision Department of Ophthalmology, Paulista School of Medicine Federal University of São Paulo, Brazil Carlos G. Arce MD, Paulo Schor MD, Mauro Campos MD Financial Disclosure: Authors do not have financial or commercial interest in mentioned equipments Dr Arce is Consultant & Territory Manager for Latin America, Vista Optics Limited, Widnes, UK; R&D Consultant, Ziemer Group AG, Port, Switzerland; Speaker, Bausch & Lomb do Brasil, and Diretor Geral, R.E.I. Comércio Ltda., Campinas, SP (cgarce@terra.com.br)

2. Traffic Light Color Distribution for Custom Color Scales • INTRODUCTION • Most topographic color scales use a normal fixed value in one of their green steps • Orbscan II and IIZ use as default the 42 D for curvature and the 600 μm for pachymetry • Galilei uses as default 43 D and 550 μm, respectively • In these cases when steps are small (≤ 0.5 D or ≤10 μm) extreme colors are achieved fast • When steps are big (≥ 1.5 D or ≥25 μm) typical patterns may be diluted or missed • Therefore, colors do not have specific or constant meaning in default scales • METHOD AND PARAMETERS • Color scales were modified by using a border line value as a fixed step in the yellow range • ORBSCAN II and IIZ (Bausch and Lomb, Rochester, NY): • Anterior Elevation : 30 μm in the 4th yellow with a 7 μm step • Posterior Elevation : 50 μm in the 4th yellow with a 13 μm step • Axial Keratometric Curvature: 47 D in the 2nd yellow with a 1 D step • Pachymetry: 500 μm in the 2nd yellow with a 15 μm step • GALILEI (Ziemer Ophthalmics, Port, Switzerland): • Anterior Elevation : 15 μm in the 2nd yellow with a 5 μm step • Posterior Elevation : 15 μm in the 2nd yellow with a 5 μm step • Sagital Anterior Curvature: 47 D in the 2nd yellow (1st orange) with a 1 D step • Pachymetry: 500 μm in the 2nd yellow (1st orange) with a 15 μm step

3. Traffic Light Color Distribution for Custom Color Scales Colors and patterns change according to size of steps in default scales Orbscan Default Scale (35 colors) Anterior and Posterior Elevation: 5 μm steps Axial Curvature: 0.5 D steps Pachymetry: 10 μm steps Orbscan Default Scales Anterior and Posterior Elevation: 10 μm steps Axial Curvature: 1.5 D steps Pachymetry: 20 μm steps

4. Traffic Light Color Distribution for Custom Color Scales Patterns and colors become independent of size of steps in these custome scales Orbscan Custom Scale (35 colors) Anterior Elevation: 7 μm steps Posterior Elevation: 13 μm steps Axial Curvature: 1.0 D steps Pachymetry: 15 μm steps Orbscan Custom Scale (70 colors) Anterior Elevation: 4 μm steps Posterior Elevation: 6 μm steps Axial Curvature: 0.50 D steps Pachymetry: 7 μm steps

5. Violet Blue Green YellowOrange Red Normal Curvature and Thickness Examples with Orbscan II “Go for it...!” Green light Flat and t Thick Cornea Flat Cornea and Normal Thickness “Why?...” Blue sign Border line Curvature and Thickness “Caution…!” Yellow light Asymmetric Border Line Curvature and Normal Thickness Very Asymmetric Steep Curvature and Normal Thickness “Stop…..!” Red light Very Asymmetric Steep Curvature and Thin Pachymetry

6. Steep Curvature and Normal Thickness Violet Blue Green YellowOrange Red Examples with Galilei Steep Asymmetric Curvature and Border Line Thickness “Caution…!” Yellow light Steep Asymmetric Anterior and Posterior Curvatures • Default Galilei Scale • for Anterior and Posterior Sagital Curvatures • and for Thickness • 2nd Yellow: • 47 D in Curvature • 500 μm in Pachymetry “Stop…..!” Red light • ANSI Scale for Anterior • and Posterior Elevation • Green at the middle: • Zero value for Anterior and • Posterior Elevation

7. Traffic Light Color Distribution for Custom Color Scales • CONCLUSIONS • By the simple strategy of using a border line value as a fixed yellow step, each color of • topographic scales begin to have the same meaning despite the step size or the • type of map • Identification of color patterns is easy and simplifies the interpretation of maps • Similar approach may be used with both the Orbscan II, IIZ and the Galilei • Everything above 47 D or below 500 μm (STEEP, THIN, or HIGH) will be orange or RED • meaning STOP! • Everything close to these selected border line value (LIMIT OF NORMALITY) will be • YELLOW meaning CAUTION! • Everything within the NORMAL values will be GREEN suggesting GO FOR IT! • BLUE will indicate the opposite (FLAT, THICK, or DEEP) of the pathologic sign