Introduction and Overview Presentation #1: Overview of AstraPro™ Custom Ablation Planning Software 12/7/2018 AstraPro Resource Presentation

General Operational Flow AstraMax Diagnostic exams (AstraMax, refraction, rigid contact lens fitting, wavefront) AstraPro Surgery planning LaserScan LSX AstraScan and AstraScan XL Configurations

AstraPro: Custom Ablation Planning Software Data is input from AstraMax which includes: Shape, pupil sizes, registration data, pachymetry, asphericity(Q), and other proprietary data points Refractive data is input New shape is calculated to maintain the eye’s natural prolate asphericity while correcting the refractive error to the best fit elipsoid model New shape is calculated with respect to the scotopic pupil AstraPro presentation #2 We take all the diagnostic data from the diskette and place it into the AstraPro software. In addition, we input manifest refraction. Then we take all this information and fit it to the scotopic pupil size. For primary surgical cases, the new ablation dimension is calculated based on the eye’s natural asphericity. AstraPro Resource Presentation

AstraPro Principals: Volume Description The volume of the ablation is described by the intersection of the existing, detected anterior surface of the cornea and the ideal cornea surface targeting the pre-operative asphericity The intersection between the measured surface and the ideal surface must be as large as the scotopic pupil seen projected at the anterior surface of the cornea Ablation volume is determined by the intersection of the best aconic surface, the manifest refraction, and the pupillary diameter. AstraPro Resource Presentation

Required Data SHAPE The shape of the cornea must be measured using triangulation methods to derive elevation with very high resolution (<3 microns)(AstraMax) Highly irregular corneas with significant discontinuities of the cornea shape will require stereo or multi-view devices that can provide accurate data for these type of cases (AstraMax) More common irregularities may be measured using more common topographers Shape is a very important basis for determining the custom ablation profile. A refraction by itself does not “see” shape. Steeper corneas of a given refraction require less of an ablation depth than do flatter corneas. If you've performed RK or other types of refractive surgery, you know that for a flatter cornea you have to produce a greater change in shape to affect the change in refraction than with a steeper cornea. So if we consider only refraction, surgery is blind to shape. You can’t base refractive surgery only on refraction. AstraPro Resource Presentation

The Shape of a Sphere Sphere = single radius of curvature Increase in effective power Sphere = single radius of curvature Snell’s Law calculates an increase in power towards the periphery due to a change in angle of incidence The characteristic of a spherical surface with gradually increasing effective power toward the periphery is called spherical aberration We use Snell’s Law to determine the custom shape. Snell's Law simply states that the angle of incidence affects power, so that a ray of light that is perpendicular to a curved surface has a different effective power than if it is ??????? More peripherally. This property is called “spheric aberration.” AstraPro Resource Presentation

Increase in effective power Spherical Aberration Increase in effective power As the pupil becomes larger at night, the larger the effect of viewing through the higher effective power of the peripheral cornea If the cornea has spherical aberrations, this results in night myopia and decreased contrast sensitivity Fortunately, the normal human cornea is not spherical. The peripheral cornea gradually flattens so that the rays of light that are incident to the cornea have a much smaller change in effective power. This is why, as our pupil becomes larger at night, we must take into account more of the peripheral cornea producing more spherical aberrations. This results in the patient having more incidences of glare and halos at night. Photopic (day pupil) Scotopic (night pupil) AstraPro Resource Presentation

Less increase in effective power Higher Power = more + Asphere: Prolate Less increase in effective power Not spherical A “normal” cornea is about 3 D flatter peripherally than centrally This is the Prolate shape Now, a normal human cornea becomes flatter by about 3 diopters as you move out peripherally. This is a “prolate shape”. Photopic (day pupil) Scotopic (night pupil) AstraPro Resource Presentation

Asphere: Prolate A normal cornea is prolate and has an average “Q” value of –0.26 Negative means that the shape flattens from the center to the periphery The normal prolate cornea has a Q value that's negative by about 0.25. Scotopic (night pupil) Photopic (day pupil) AstraPro Resource Presentation

Asphere: Oblate A sphere has no asphericity: Q = 0 Asphere surfaces that steepen toward the periphery have + asphericity (Q>0) and are termed Oblate Myopic refractive surgical treatments increase + asphericity, i.e., moves shape towards Oblate Exaggerates the effects of spherical aberration, i.e., more night vision problems The opposite of a prolate cornea is an oblate cornea, where the cornea becomes steeper as you move toward the periphery. This is an exaggerated form of spheric aberration. AstraPro Resource Presentation

Prolate Vs. Oblate (Asphericity) Oblate (Q > 0) Prolate (Q < 0)

Examples of Aspheric Values Asphericity “Q” Cornea -2 Severe kerataconus -1 Mild kerataconus -.25 Normal cornea Sphere +1.00 8 cut RK +2.00 16 cut RK In keratoconus, the cornea is much steeper in the center than it is toward the periphery. So, we exaggerate the Q value and it becomes more minus. When RK was performed, the center of the cornea was flattened so that there was actually a positive increase in Q value. The result was problems with spheric aberration and night vision. Here are some examples of aspheric values. The degree to which the cornea deviates from -0.25 or prolate determines the degree of spheric aberration. AstraPro Resource Presentation

Required Data SHAPE SCOTOPIC PUPIL The projection of the scotopic pupil on the anterior surface of the cornea is measured in dark conditions with an infrared instrument (AstraMax) Shaping the ablation profile to provide full coverage of the scotopic pupil will minimize aberrations under dimly lit conditions After shape, the second most important aspect to consider is the scotopic pupil size. We want to make sure that the aspheric shape completely covers the nighttime pupil size. AstraPro Resource Presentation

Required Data SHAPE SCOTOPIC PUPIL MANIFEST REFRACTION The subjective refraction is the most important parameter for the determination of the ideal aconic surface for the cornea The third required data point is manifest refraction. An accurate manifest refraction should create the differential between the best fitting aconic surface, or the best aspheric surface, and the new aspheric surface. This is the differential in tissue that's removed beyond taking out the irregularities in the cornea. AstraPro Resource Presentation

AstraMax Data Anterior Cornea Posterior Cornea Spatial Resolved Refractive Error The data points of our best manifest refraction are calculated and put into the AstraMax. Corneal Thickness and Anterior Chamber Depth Scotopic Pupil Size AstraPro Resource Presentation

Calculating the Ideal Aconic Surface The vectorial sum of the refractive properties of the anterior corneal surface and the subjective refraction = the new surface The new targeted surface will be optimized to respect the cornea’s pre-operative asphericity, i.e., to preserve the natural prolate nature of the cornea [This slide has no corresponding text] AstraPro Resource Presentation

AstraPro: Summary of Features Imports Corneal Topography Optimized Treatment Planning Advanced Surgical Planning Safety Features

Imports Corneal Topography Reduces the roughness of the eye Allows treatment of irregular corneas Allows treatment of asymmetric corneas

Circular Treatments Circular, tissue-saving ablation profiles Profile centered in pupil Optimizes optical zone for astigmatic treatments

Optimized Treatment Planning Circular Treatments Pupil Center Offset Blend Zone Ablation Modulation Function (AMF)

Circular Vs. Elliptical Treatments Pupil Elliptical zone along the minor axis of the astigmatism (too much ablation outside the pupil) Elliptical zone along the major axis of the astigmatism (does not cover optical zone of pupil)

Pupil Center Offset Pupil center offset from the visual axis Final surface is offset from the pupil center Saves tissue by not having to increase the optical zone to compensate for the offset

Pupil Center Offset Pupil Pupil Center Area inside pupil not treated when OZ = Pupil Visual Axis

Pupil Center Offset Pupil Center Pupil Additional treatment causes a much deeper ablation when OZ > Pupil Visual Axis

Pupil Center Offset Visual Pupil Axis Center Optical Zone Initial Surface Final Surface Optical Zone

Blend Zone Blend between optical and treatment zones Gaussian function ensures continuous curve along the target eye surface Profile is blended to the target eye, not to a flat surface

Blend Zone

Ablation Modulation Function Maintains or improve prolate shape Corrects for laser fluence reduction in periphery This algorithm may be extensible to the laser platform directly

Laser Fluence Reduction B1 Fluence = Area Energy B2 The area of B2 is larger than the area of B1, so B2 has less fluence if the energy remains constant.

Advanced Surgical Planning Aspheric Ellipsoid Model Contact Lens Over-Refraction Method Target Refraction Optical and Treatment Zones Nomogram Adjustment Target Z-Axis Offset Effective Refractive Change

Aspheric Ellipsoid Model Initial and final eye surfaces Parameters: K1, K2, axis, asphericity (Q), defined as the apical keratometry Corrects for the keratometric index of refraction Novel algorithm to add spherical refraction to aspherical surfaces

Contact Lens Over-Refraction CLOR method for irregular or asymmetric surfaces Set of rigid contact lenses May provide best correction

Target Refraction Allows surgeon to record target refraction separately from spectacle or contact lens refraction Ideal for mono-vision patients

Optical and Treatment Zones The default OZ is set to the scotopic pupil diameter or 6mm, whichever is larger The TZ is set to 1mm (SER myopia) or 2.5mm (SER hyperopia) larger than the optical zone. The surgeon may modify the OZ and TZ within the range 3-9mm

Nomogram Adjustment Persistent Sphere/Cylinder adjustments separately for myopic astigmatism, hyperopic astigmatism, and mixed astigmatism Sphere/Cylinder adjustment may be modified for individual treatments Applied to refraction, prior to AMF

Target Z-Axis Offset Provides an offset to the Target Z-Axis Automatically computed by the software Optimizes treatment plan (saves tissue) for irregular surfaces

Effective Refractive Change Estimated from the corneal topography and apical keratometry Computed in terms the surgeon can understand, using the spherical approximation of the initial and final surfaces

Safety Features Treatment depth computed normal to the eye surface and compared with pachymetry at all points Warning messages and restrictions Patient data (name, gender, eye) provided for visual confirmation Advanced Visual Display

Visual Display Keratometric axial power map duplicates image from topographer, as a double-check Preop elevation difference map from best fit asphere of keratometry Predicted postop elevation difference map from best fit asphere of keratometry Ablation profile (depth map)

AstraPro: Planning Screen Topography data is displayed After capturing the patient exam on the AstraMax, the AstraPro planning software will be used to plan the ablation. On the windows based main planning screen, we'll touch the import patient data button. Patient Data is automatically imported form AstraLink AstraPro Resource Presentation

AstraPro: Planning Screen Surgical parameters entered This screen allows us to do iterative planning, surgeons can adjust some of the parameters to see what the postoperative results will look like after the ablation has been performed. Resultant treatment dimensions AstraPro Resource Presentation

AstraPro Configuration Screen Here is the pre-operative topography of the ablation profile that we planned just prior to surgery. This is a subtraction. If we take the preoperative topography and the subtraction, we will get the expected ideal post-operative shape. AstraPro Resource Presentation

AstraPro Main Screen With 3D Rotation and Inspection The planning screen allows the surgeon an opportunity to change the ablation so it is larger. Here the surgeon has specified an optical zone that is larger than the scotopic pupil size as his choice, and has also modified the asphericity. Let's move back so we can see what that difference was from the original plan. You can see the theoretical size of the postoperative ablated zone as well as the new optical zone based upon some additional parameters that the physician chose as modifications. AstraPro Resource Presentation

AstraPro Planning Screen With 3D Rotation and Inspection

Summary The calculations to optimize the new corneal shape targets the natural pre-operative asphericity Potentially results in: Decreased spherical aberrations Improved night vision Improved contrast sensitivity The result of all these calculations is that the natural asphericity of the cornea is maintained, which decreases spherical aberrations by removing the irregularities from the cornea. This is done by fitting a best aconic surface to the cornea in order to get better nighttime vision and potentially improved visual acuity, ultimately resulting in satisfied patients and clinical outcomes. End of Presentation #2 on AstraPro. AstraPro Resource Presentation