Disclosure Slide Types of Corneal Topographers

5/1/2015
Utilizing Technology in the
Trenches to Improve Contact
Lens Performance
Disclosure Slide
• Dr. Ed Bennett
• Randy Kojima
• No conflicts
• Research and
Development Director,
Precision Technology,
Vancouver, Canada
• Clinical Advisor and
Speaker to Medmont
International
Edward S. Bennett
O.D., M.S.Ed., F.A.A.O., F.S.L.S.
Randy Kojima
FAAO, FSLS, FIAO
K-Readings:
Diameter of Measure
Types of Corneal
Topographers
3mm
10.5mm Corneal GP
14.0mm Soft Lens
15+mm Scleral
Reflection
Projection
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5/1/2015
Reflection Systems
Placido
Reflection
LED
Reflection
Placido Topography
Profilometry
Reflection
Placido Topography
Placido Topographers
2
5/1/2015
Profilometry Topography
Profilometry Topography
Projection Topography
Projection Topography
3
5/1/2015
Analysis Options
Projection Topography
Axial, Sagittal, Power
Axial
Tangential
Elevation
Refractive
Wavefront
Height
Tangential,
Instantaneous, True
4
5/1/2015
Elevation
Contact Lens Module
How can topography help us
with soft contact lenses?
Topography and vision
analyis
Axial Interpretation
5
5/1/2015
Measuring Visible Iris
Diameter
Corneal Anatomical Features
& Their Contribution to Sag Height
1. Corneal
Diameter
Manual Measuring Tools
Automated Iris Definition
Measure Visible Iris Diameter
10mm
11mm
12mm
13mm
Graham Young
Corneal Topography and
Soft Multifocals
6
5/1/2015
Acuvue Oasys -3.00/ +2.50 Add
Air Optix -3.00/ +2.50 Add
Biofinity Distance Center:
-3.00/ +2.50 Add
Biofinity Near Center:
-3.00/ +2.50 Add
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Purevision: -3.00/ +2.50 Add
Topography and GP
Lenses
Analysis
Elevation Differential
≤350 Microns
+200um
Axial Interpretation
Tangential Interpretation
-150um
Elevation: +200
Depression: -150
Differential: 350um
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5/1/2015
N = 87 Patients
127 CL Fits
Less than 350um
Flat Meridian
Greater than 350um
Patients with 350um or less of corneal elevation difference
(along the greatest meridian of change) have an 88.2%
chance of success with a corneal GP lens.
Steep Meridian
Topography and GP
Lenses
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5/1/2015
Case CB: Right Eye
Elevation Map
+175µm
+250µm
+160µm
-200µm
Elevation: +250um
Depression: -200
Differential: 450
+0.50 -5.75 x 85
Keratoconus GP lens:
Horizontal Meridian
Keratoconus GP lens:
Vertical Meridian
8.40 10.2mm
36 microns
320 microns
270 microns
8.40 10.2mm Trial
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5/1/2015
Scleral is the best option
for this patient
Calculating Scleral Lens
Sagittal Depth
Scleral Lens Shape
Scleral Depth Calculation
Sag µm
°
10mm
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5/1/2015
Calculating the Scleral Sag
ICD 16.5mm Scleral Lens
4400 micron Sag
• Estimated Sag at 15mm
+
• Initial apical clearance:
400um
+
• Required Scleral Lens:
4400um
How does the topographer
help in orthokeratology
Subtractive Map Outcomes
Bulls-eye
Smiley Face
Central Island
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How do we read
Axial Subtractive Maps?
How do we read
Tangential Subtractive Maps?
Bulls-eye Response:
Axial Subtractive Map
Bulls-eye Response:
Tangential Subtractive Map
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Smiley Face Response:
Axial Subtractive Map
Smiley Face Response:
Tangential Subtractive Map
Central Island Response:
Axial Subtractive Map
Central Island Response:
Tangential Subtractive Map
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5/1/2015
Subtractive Maps Are Key to
Orthok Analysis
Summary
Thank-you!
Edward S. Bennett
O.D., M.S.Ed., F.A.A.O., F.S.L.S.
Randy Kojima
FAAO, FSLS, FIAO
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