TABLE OF CONTENTSIntroductionPage1Product Description1Actions3Indications (Uses)4Cautions4Warnings4When Not To Wear Lenses4Possible Problems4Selection Of Patients4Fitting ConceptPredicting Lens Results45Risk Analysis5Fitting Paragon CRT And Paragon CRT 100 Contact LensesFor Corneal Refractive Therapy6How To Fix Fitting Problems17Understanding Poor Fit Dynamics24Problem Solving Table27Follow-Up Care28Recommended Initial Wearing Schedule28Myopic Reduction Maintenance Lens (Retainer Lens) Wearing Schedule29Handling Of Lenses29Patient Lens Care Directions29Vertex Distance And Keratometry Conversion Charts29How Supplied29Reporting Of Adverse Reactions30Instructions for Use (enclosed)ii

INTRODUCTIONParagon CRT and Paragon CRT 100 Contact Lenses for Corneal Refractive Therapy produce a temporaryreduction of myopia by reversibly altering the curvature of the cornea. The Paragon CRT and CRT 100 contactlenses are manufactured from Paragon HDS and Paragon HDS 100 respectively. A slight reduction of thecurvature of the cornea can reduce the excessive focusing power of the myopic eye. If the amount of cornealreshaping is precisely controlled as is the objective of the CRT lens design, it is possible to bring the eye intocorrect focus and completely compensate for myopia. After the contact lens is removed, the cornea retains itsaltered shape for all or most of one’s waking hours. The lens is designed to be worn overnight with removal duringfollowing day. The Paragon CRT and Paragon CRT 100 lenses must be worn at night on a regular schedule tomaintain the corneal reshaping, or the pre-treatment myopia will return.PRODUCT DESCRIPTIONParagon CRT contact lenses are manufactured from Paragon HDS (paflufocon B) and ParagonCRT 100 contact lenses are manufactured from Paragon HDS 100 (paflufocon D). The lenses are designed tohave congruent anterior and posterior surfaces each consisting of three zones:1. The central spherical zone.2. A mathematically designed sigmoidal corneal proximity “Return Zone”.3. A non-curving “Landing Zone”.The lens design also includes a convex elliptical edge terminus smoothly joining the anterior and posteriorsurfaces.Paragon CRT and Paragon CRT 100 Contact Lenses for Corneal Refractive Therapy are to be worn overnightwith removal during all or part of each following day. Both materials are thermoset fluorosilicone acrylatecopolymer derived primarily from siloxane acrylate, trifluoroethyl methacrylate and methylmethacrylate with awater content of less than 1%. These contact lenses for Corneal Refractive Therapy are available as lathe cut firmcontact lenses with blue and green tints. The blue tinted lens contains D&C Green No. 6. The green lens containsD&C Green No. 6 and Perox Yellow No. 9 2-phenyl-3H-pyrazol-3one). These products may be plasma treated.Detailed DescriptionGenerally the central base curve is chosen to be flatter than the curvature of the central cornea by an amount suchthat if the cornea were to take on this lens curvature a significant reduction in myopia would be expected. The lensis fitted to allow this zone to contact the central corneal apex. Until such time as the cornea has taken on thecurvature of this zone of the lens, it is expected that this zone will gradually diverge from the corneal curvature,thus rising away from it with a maximum deviation at the edge of the zone.The first zone peripheral to the central base curve, the Return Zone, has a sigmoidal shape that smoothly joins thiszone to the central zone and the third element. The sigmoid will be mathematically designed to return the posteriorlens surface to closer proximity to the cornea than it would have had if the geometry of the central base curve werecontinued through this zone. This zone is conveniently described by referring to the width and depth of a rectanglewhich would enclose a cross section through the Return Zone (see drawing page 4). The width of the zone is fixedat 1 mm while the fitter determines the Return Zone Depth (RZD).The third element, referred to as the Landing Zone, has the form of a truncated cone and is concentric to theReturn Zone. This element is intended to be tangential to the cornea at a specified diameter but not initially incontact with it. Since the Landing Zone naturally deviates from the cornea peripheral to the point of tangentialcorrespondence, there is no need for an additional peripheral curve to give “edge lift”. Fluid forces arising fromthe approximation of Landing Zone and cornea participate with other factors in stabilizing the lens orientation onthe eye. The Landing Zone is characterized by the angle that its cross section makes with the horizontal and by itschord diameter; both parameters are selected by the fitter.1

The last and most peripheral element, the edge terminus, deviates from the uncurved Landing Zone and curvesaway from the underlying cornea to merge with the anterior surface thereby forming the edge of the lens. Thiszone follows the prescribed shape of a convex ellipse thereby “rolling” the lens surface away from the corneapromoting comfort. This terminus is not to be confused with a “peripheral curve” frequently found in RGPdesigns. Such peripheral curves are concave toward the cornea with a radius specified to maintain nearly parallelalignment with it. Such lenses also have a separate edge contour, which is created by grinding and polishing theedge but its shape is typically arbitrarily derived by the nature of the processes and lens edge thickness. The CRT edge is pre-specified and equivalent in all lenses regardless of their other parameters.Paragon CRT and Paragon CRT 100 contact lenses are used to temporarily reshape the cornea to change itsrefractive power with a resultant reduction in the pretreatment refractive error. Corneal tissue is redistributedwithout significant alteration of its physiology. The change in shape is the result of gentle mechanical pressurefrom the flattened central zone of the lens augmented by the availability of unoccupied volume beneath the Returnand Landing Zones of the lens. After wearing of the lens, the cornea typically demonstrates an increased radius ofcurvature in the central area and a decreased radius of curvature in the paracentral area allowed by the clearancewithin the outer portion of the optic zone and the Return Zone of the lens.Although rarely required, the anterior central curve is selected to provide any necessary optical power to correctresidual refractive error not corrected by the optical and mechanical effect of the posterior base curve and the tearlens formed between it and the cornea. Typically this surface and the other anterior surfaces exactly parallel theirposterior counterparts. Lens thicknesses in the three zones are not dependent on lens parameters but have beenselected to maximize oxygen transmission, stability and comfort.LENS PARAMETERS AVAILABLE (See drawing)Overall Diameter (D)Central Base Curve RadiusOptical Zone Semi Chord (OZ)Return Zone Width (w)Return Zone Depth ( )Landing Zone RadiusLanding Zone Angle ( )Landing Zone Width (LZW)Edge Terminus Width (P)Dioptric Powers9.5 to 12.0 mm6.50 to 10.50 mm2.50 to 3.50 mm0.75 to 1.5 mmto 1.0 mmto infinity-25o to –50o0.5 to 2.75 mm0.04 mm to LZW-2.00 to 2.00 DioptersOZWLZWPDFD2

ATTRIBUTES OF THE PARAGON CRT LENS (paflufocon B)Refractive IndexLuminous Transmittance (Blue)Wetting Angle (Receding Angle) Wetting Angle (Contact Angle) Specific GravityHardness (Shore D)Water Content1.449 (Nd at 25 C)95%14.7 62º1.1684 1%ATTRIBUTES OF THE PARAGON CRT 100 LENS (paflufocon D)Refractive IndexLuminous Transmittance (Green)Wetting Angle (Receding Angle) Wetting Angle (Contact Angle) Specific Gravity1.442 (Nd at 25 C)95%42 70º1.10Hardness (Shore D)Water Content79 1% Determination of the Spectral and Luminous Transmittance, ISO 8599:1994 Adapted from: A New Method for Wetting Angle Measurement; Madigan, et. al., International Eyecare, 01/1998. vol. 2, no.1, p.45 Sessile Drip Technique per ANSI Z80.20, 8:11 OXYGEN PERMEABILITY - CRT LENS DESIGNMaterialPowerOxygenPermeability(ISO Method*)Dk x 10-11HDS 100HDS 100HDS 100HDSHDSHDS-2.00Plano 2.00-2.00Plano 2.00100100100404040CenterThickness(mm)Harmonic MeanThickness** (mm)OxygenTransmissibility (ISO)Dk/l 0.1480.1490.161616060272725* (cm2/sec) (mL O2)/ (mL x mm Hg) ISO/ANSI Method, ISO 9913-1** Sammons, W.A., “Contact Lens Thickness and All That”, The Optician, 12/05/80.ACTIONSParagon CRT and Paragon CRT 100 Contact Lenses for Corneal Refractive Therapy produce a temporaryreduction of myopia by changing the shape (flattening) of the cornea, which is elastic in nature. Slightly reducingthe curvature of the cornea reduces the excessive focusing power of the myopic eye, and if the amount of cornealflattening is properly controlled, it is possible to bring the eye into correct focus and completely compensate formyopia.Contact lenses rest directly on the corneal tear layer and can gently influence the corneal shape. Regular contactlenses are designed to cause little or no effect but Paragon CRT and Paragon CRT 100 Contact Lenses forCorneal Refractive Therapy are designed to purposely flatten the shape of the cornea by applying gentle pressureto the center of the cornea during sleep.After the contact lens is removed, the cornea retains its altered shape for all or most of one’s waking hours. Thelenses are designed to be worn overnight with removal during the following day. The CRT lens design must beworn at night on a regular schedule to maintain the corneal reshaping, or the myopia will revert to the pretreatmentlevel.3

INDICATIONS (USES)Paragon CRT (paflufocon B) and Paragon CRT 100 (paflufocon D) Rigid Gas Permeable contact lenses forCorneal Refractive Therapy are indicated for use in the reduction of myopic refractive error in nondiseased eyes.The lenses are indicated for overnight wear in a Corneal Refractive Therapy fitting program for the temporaryreduction of myopia up to 6.00 diopters in eyes with astigmatism up to 1.75 diopters. The lenses may bedisinfected using only a chemical disinfection system.Note: To maintain the Corneal Refractive Therapy effect of myopia reduction lens wear must becontinued on a prescribed wearing schedule. Failure to do so can affect daily activities (e.g., nightdriving), visual fluctuations and changes in intended correction.CAUTIONSReference the so entitled section found in the enclosed Instructions for Use.WARNINGSReference the so entitled section found in the enclosed Instructions for Use.WHEN NOT TO WEAR LENSESReference the so entitled section found in the enclosed Instructions for Use.POSSIBLE PROBLEMSReference the so entitled section found in the enclosed Instructions for Use.SELECTION OF PATIENTSPatients are selected who have a demonstrated need and desire for a refractive reduction by Contact Lens CornealRefractive Therapy with rigid gas permeable contact lenses and who do not have any of the contraindications forcontact lenses previously described. Paragon CRT and Paragon CRT 100 Contact Lenses for CornealRefractive Therapy are indicated for myopic patients who desire not to wear vision correction devices during thedaytime hours, but still require the ability to see clearly during that time.Paragon CRT and Paragon CRT 100 contact lenses for overnight Contact Lens Corneal Refractive Therapyare primarily intended for patients who are within the following parameters.Refractive ErrorKeratometryVisual Acuity-0.5 to -5.50 diopters with up to –1.75 diopters of astigmatism37 to 52 diopters20/20 to 20/1000FITTING CONCEPTParagon CRT and Paragon CRT 100 Contact Lenses for Corneal Refractive Therapy are intended to be fitted soas to flatten the central cornea and thereby reduce myopia. This goal is accomplished by the lens design and themanner in which the lens is fitted. The goal in fitting is a well-centered lens having a base curve that is flatter thanthe flattest meridian of the cornea by at least the attempted treatment power in that meridian. A well-fit lens willhave proper sagittal depth to prevent z-axis tilt and achieve centration over the corneal apex. A well-fit lens willalso have a proper sagittal depth profile to prevent bearing at the Return Zone – Landing Zone junction or heavybearing in the periphery of the lens. The lens will demonstrate central corneal applanation, paracentral lens-corneaclearance and Landing Zone-cornea tangential correspondence.4

The Paragon CRT and Paragon CRT 100 Contact Lens Corneal Refractive Therapy fitting system utilizes thefollowing fixed parameters. Optic Zone 6.0 mmReturn Zone Width 1.0 mmCenter thickness 0.15 mm 0.01The optic zone and Return Zone Width may be changed in rare circumstances by means of a special order.Smaller optic zones may be appropriate in unusually small corneal diameters and in the case of target reductionsgreater than 5.00 diopters. For corneal diameters greater than 10.8 mm and target improvements less than 5.00diopters, the standard parameters are recommended.There are four primary fitting objectives: Provide a base curve that will reshape the underlying cornea to a resultant curvature that producesemmetropia or low hyperopia. Provide an initial clearance at the point of tangential correspondence of the Landing Zone and peripheralcornea that will allow the corneal apex to retreat approximately 6 microns per diopter of treatment. Provide a Landing Zone that has the proper angle to provide a midpoint of tangency to the underlyingcornea near the midpoint of the zone itself. Provide a lens diameter that, in conjunction w