MAKE SENSE OF KERATOCONUS

MAKE SENSE OF KERATOCONUS OVERVIEW OF KERATOCONIC OPTIONS FOR ALL TYPES OF KERATOCONUS & REVERSE GEOMETRY CORNEAS RIGID Scleral Semi-scleral corneal RGP HYBRID Rigid centre Soft skirt SOFT Disposable Lathe cut soft Customised lathe cut soft THINNER LENSES DELIVER INCREASED OXYGEN TO THE CORNEA Increased oxygen supply helps maintain a healthy cornea – particularly important for post graft cases. ULTRA-THIN DESIGN DELIVERS ENHANCED PERIPHERAL FIT KeraSoft Thin's unique, thinner design increases lens flexibility allowing it to drape better over the peripheral cornea. COMPLEX CASES BENEFIT FROMUNIQUE KERASOFT THIN DESIGN Improved draping reduces tear pooling under the lens, stabilising visual acuity.

MAKE SENSE OF KERATOCONUS CORRECT THE PROBLEM DON’T MASK IT PERIPHERY OF THE LENS Acts as a stable framework and supports the central optic, preventing it from replicating severe distortion. NON-REGULAR ASTIGMATISM Is transmitted through the central optic as regular astigmatism which is then fully corrected.

MAKE SENSE OF KERATOCONUS PARAMETER RANGE FITTING SET PARAMETERS Base Curve Diameter Sphere Cyl Axis Peripheries SMC 7.40 TO 9.40 mm 14.00 14.50 15.00 mm +/- 30.00 DS -0.50 to -15.00 DC 1°- 180° (1° steps) FLT4 to FLT1 STD STP1 to STP4 Up to 2 sectors The Standard Fitting Set is available with 8 x 14.50 mm diameter lenses comprising: 6 x STD periphery Base Curve 7.80 to 8.80 in 0.20 mm steps 1 x FLT2 periphery Base Curve 8.20 (for Nipple Cones) 1 x STP2 periphery Base Curve 8.60 (for post-graft and other reverse-geometry corneas) MATERIAL Filcon V 3 SiH, 74% water** (3 month replacement) Filcon II 3, 77% Water (12 month replacement) It is possible to order a powered KeraSoft Thin lens from KeraSoft IC Plano Trial Lens. However, if a KeraSoft IC powered lens is ordered from a KeraSoft Thin Plano Trial Lens, the final lens may fit differently due to the thicker profile shape.

MAKE SENSE OF KERATOCONUS WHY CHOOSE THIN? ON EYE INVESTIGATION DEMOGRAPHICS 24* subjects – 48 eyes INTERNAL STUDY Subjects chosen were wearing KeraSoft IC lens with VA 6/7.5 (0.80) or better Issued with new KeraSoft IC and Thin lenses with identical parameters Wore each pair for a week and asked to attend review with lenses they preferred Corneal Type No of subjects Central Cone 13 Offset Cone 14 Low Cone/PMD Post-graft 4 INTACS 2 Post-hydrops 1 *13 subjects had undergone corneal collagen crosslinking (CXL) treatment. METHODOLOGY Visual Acuity (VA) was measured using decimal notation. Baseline VA was established with KeraSoft IC and the variance from this value was recorded with KeraSoft Thin. Subjects were asked to score comfort levels on a scale of 1 to 5 during home trials. Fit was assessed on the slit lamp using the MoRoCCo VA assessment technique.

MAKE SENSE OF KERATOCONUS WHY CHOOSE THIN? FINAL VA COMPARISONS LOW CONE KERATOCONUS POST-GRAFT – INTACS SUBJECTS VARIANCE IN VA WITH DIFFERENT CORNEAL TYPES For all but 3 eyes, VA was the same or improved with KeraSoft Thin VARIANCE (DECIMAL VA) VARIANCE (DECIMAL VA) CENTRAL KERATOCONUS OFFSET CONES CHART COLOUR KEY VARIANCE (DECIMAL VA) VARIANCE (DECIMAL VA) INCREASED VA DECREASED VA

MAKE SENSE OF KERATOCONUS WHY CHOOSE THIN? CONCLUSION KeraSoft Thin gives the same or better VA than KeraSoft IC in nearly all cases and especially for low cones and post grafts KeraSoft Thin therefore delivers the same performance in a thinner lens, therefore supplying better oxygen to the cornea. Many hospitals now use KeraSoft Thin as their first choice lens to fit keratoconus and irregular corneas.

FIRST CHOICE LENS

FIRST CHOICE LENS BEFORE YOU FIT CORNERSTONES OF essential information FITTING THIN Tangential Topography Map BASECURVE CALCULATOR Calculates First Choice Lens from the Tangential map KeraSoft Thin Base Curve can be calculated from the Tangential map. This is accurate around 80% of the time and only small adjustments need to be made for the next lens SPEC Rx Gives good starting point for over refraction MoRoCCo VA Once the lens is on eye, use MoRoCCo VA Fitting characteristics to assess fit. Based on Movement, Rotation, Centration, Comfort and Over-Refraction VA TECHNICAL SUPPORT All of this information is very useful for our technical support team if you ask for help with a fitting. HISTORY Any surgeries – eg. Post graft Has the Px had refractive surgery? INTACS CXL REFRACTION SPECTACLE Rx BVD HVID

FIRST CHOICE LENS BASECURVE CALCULATOR EXAMPLE Tangential VS Axial MEASUREMENTS USED FOR BC CALCULATION Central Sim-K readings Steep and Flat Sim Ks from 5mm ring Results in orange indicate Correction Factor SETTING THE MAP Tangential Curvature map Numerical data Polar grid Normalised Prediction – 8.70 Prediction – 7.62 Axial maps do not work with the Base Curve Calculator Actual lens 8.60:15.00

AID TO UNDERSTANDING CONE POSITION SPEC RX/K READINGS VS CONE TYPES CENTRAL CONES LOW CONES POOR TO BETTER SPECTACLE VA STEEP TO FLAT CENTRAL K READINGS HIGH MINUS/LOW CYL TO MINUS/HIGH CYL

FITTING GUIDANCE

FITTING GUIDANCE FIRST CHOICE LENS USE 14.50 LENS WITH BASE curve predicted by base curve calculator INSERT LENS OBSERVE LENS STRAIGHT AWAY ON SLIT LAMP If obviously tight or flat, remove lens and move to next choice ASSESS LENS ON SLIT LAMP IF LENS FIT APPEARS REASONABLE - CONTINUE WITH ASSESSMENT CHECK COMFORT CHECK COMFORT AS YOU ASSESS THE LENS - SUPPORTS FITTING INFORMATION OVER REFRACTION USE SPECTACLE RX AS STARTING POINT - VA PRE AND POST BLINK WILL INFORM ABOUT FIT

FITTING GUIDANCE MoRoCCo VA Characteristics MOVEMENT Up to 2mm is acceptable as long as the patient is comfortable. ROTATION Engraving mark should sit at 6 o’clock. Rotation of the lens that does not change on upward gaze is classed as stable, indicating a tight fit. Rotation of the lens that changes on upward gaze is classed as unstable, indicating a flat fit. CENTRATION Centred lens indicates an optimal fit. Decentred or dropping lens indicates a flat fit. COMFORT An optimal lens is comfortable. A tight lens may comfortable at first but will then start to be uncomfortable. Non-settling discomfort indicates a flat fit. VA quality is assessed using over refraction and should be stable pre and post blink

FITTING GUIDANCE MOVEMENT ON EYE PERFORMANCE DURING BLINK CYCLE FLAT FIT TIGHT FIT OPTIMAL FIT

FITTING GUIDANCE ROTATION CENTRATION Stable Rotation Centred Lenses TIGHT Lens Engraving mark stays generally in one position whatever the direction of gaze - especially in upwards gaze. Centred Lenses Represent OPTIMAL or tight fit. Unstable Rotation FLAT Lens Engraving mark moves position on blink and ends to fall towards the 6 o'clock position on upwards gaze in one position whatever the direction of gaze. Decentred Lenses Represent a flat fit. Centred lenses that drop excessively on upwards gaze May represent a good fit on a cornea with a steeply curved inferior area, if all other factors are fine. Rotation of more than 10-15 degrees indicates a poor fit

FITTING GUIDANCE COMFORT VA Good comfort Non-settling discomfort Indicates a good fit if the comfort level is maintained through the fitting process. If the lens begins to become uncomfortable, particularly in one position, over time - this indicates a tight fit. FINE TUNING METHOD FLAT FIT VA worse after blink, then improves OPTIMAL FIT VA stable pre and post blink TIGHT FIT VA better after blink, then gets worse Non-settling discomfort If an inserted lens continues to be uncomfortable during the fitting process, indicates a flat fitting lens Patients who have previously worn RGPs may have a different expectation of comfort from neophytes VA should be equal or better than Spec VA If VA is really poor, then fit is usually poor and patient will be “guessing” whether better or worse after blink.

FITTING GUIDANCE DIAMETER & PERIPHERY GUIDE CORNEAL TYPE PERIPHERY DIAMETERS Central (mild to moderate) Standard 14.50 Nipple cone (advanced) Flat 2 or Flat 3 Low or decentred cone (mild to moderate) 14.50 & 15.00 Lowe or decentred cone (advanced) SMC (STD:STP1 or STD:STP2) Post-graft | post-refractive surgery Complex post-graft | post-refractive surgery Steep 2 or SMC design Improving the fit Always use STD lenses as First Choice Lens Where lenses are dropping on low cones, increase diameter to 15.00 keeping Base Curve the same. Only look at periphery changes if this does not work.

FITTING GUIDANCE DIAMETER & PERIPHERY CHANGES WHEN TO CHANGE DIAMETER Low cones/Post grafts Always start with Base Curve Calculator and 14.50 diameter If lens drops excessively on upward gaze but VA is generally acceptable, move to 15.00 with SAME base curve IF DIAMETER CHANGES DO NOT WORK Low cones may require a "tuck" in the inferior portion only (SMC) Post grafts may need all round STEEP periphery Nipple cones will need a FLAT periphery

FITTING GUIDANCE DIAMETER & PERIPHERY CHANGES STEEP PERIPHERY FLAT PERIPHERY WHEN TO USE Only use for post surgical – Do NOT use to tweak fitting WHEN TO USE For Nipple Type Cones where periphery is much flatter than central area Contact lens Contact lens Contact lens Contact lens Tears trapped underneath lens Better fit, no tears trapped Cornea Cornea Cornea Cornea FITTING TIPS Lens A – Great VA but flutes at edge Lens B – Great fit but VA clearer after blink Use Lens A for Base Curve and Lens B for Periphery FITTING TIPS All STD lenses give poor VA – going steeper and flatter does not significantly change anything. Mid periphery bubbles may be present. FROM FITTING SET Try 8.20:FLT2 from the set as a starting point. If VA is improved, you can fit trial lenses with base curves flatter or steeper but using FLT2 periphery EXAMPLE Lens A – 8.80:STD Lens B – 8.20 Final lens – 8.80:STP3

FITTING GUIDANCE BASECURVE CALCULATOR BASECURVE CALCULATOR NIPPLE CONE FITTING ISSUES BASECURVE CALCULATOR REVERSE GEOMETRY POST-GRAFT EXAMPLE: CALCULATOR GIVE 8.40 VA 6/36 variable, fit poor and changing base curve does not improve anything. The calculator is fitting to overall shape but cannot drape over the nipple cone. Steepen Base Curve while keeping periphery the same. CALCULATOR CAN STILL GIVE A GOOD STARTING POINT Always try increasing diameter first before using peripheral change or SMC 8.40 8.20 8.00 7.80 Final lens – 7.80:14.50:FLT3 Actual lens 8.60:15.00

FITTING GUIDANCE SECTOR MANAGEMENT CONTROL ORDERING SECTOR MANAGEMENT CONTROL CHANGE UP TO TWO SECTORS INDEPENDENTLY OF EACH OTHER USES Steepening inferior section if going to 15.00 mm diameter does not work. Fitting complex post surgical cases. CLASSIC SMC DESIGN Blended Area Blended Area Sector 1 Blended Area Blended Area A1=30 A2=150 A3=220 A4=320 Sector 2

TROUBLESHOOTING Rotation greater than 10-15 So what did I do wrong? Even if the trial lens fit looks “stable”, it is a poor fit with this much rotation - when power is applied, it will rotate to another position Only accept a rotation if you get the same result no matter what lens you use So what did I do wrong? Not assess the lens straight away Leaving the lenses 15-20 minutes before observation can reduce the movement of a flat lens significantly Ignoring rotation Rotation suggests there is something wrong with a fit, certainly more than 15 degrees Only concentrating on movement Check centration and quality of VA after the blink Not being fully aware of corneal shape E.g. flat corneal periphery, low cone Poor fit, good VA A very flat lens can give good VA, just as it can with an RGP - once you apply power, the fit will become destabilised Reassess fit with Base Curve Calculator. If no topography, try going steeper with base curve and assess using MoRoCCO. If fit improves but VA is worse, use original base curve and increase diameter. Poor results on collection Original fit was not actually optimal This will happen if lenses left too long for assessment. Trial set lenses were mixed up if lenses are being re-used Not enough cyl was ordered - always check topography for amount of astigmatism and ensure you at least try that in the over refraction.

Patient AV Central K’s: 7.97 x 8.17 5mm K’s: 7.50 x 9.30 BC Calculator Lens: 8.80:15.00 Plano STD Feedback: Mo: 1mm Ro: 10˚ stable – upward and straight ahead gaze C: Good Co: Good VA Clearer after blink New Trial: 9.00:15.00 Plano STD Mo: 1.5mm Ro: 2˚ VA No Fluctuation 6/6 ( -0.25/-1.00 x 95 ) Powered Lens: 9.00:15.00 -0.25/-1.00 x 95 STD

Patient AS Central K’s: 6.83 x 7.85 5mm K’s: 7.60 x 9.00 BC Calculator Lens: 8.60:14.50 Plano STD Feedback: Mo: 1.50mm Ro: None - Stable – upward and straight ahead C: Drops on upward gaze Co: Good VA Worse after Blink New Trial: 8.40:15.00 Plano STD Mo: 1mm Ro: None – Stable upward and straight ahead C: Good VA No Fluctuation 6/5 ( -1.50/-1.75 x 135) Powered Lens: 8.40:15.00 -1.50/-1.75 x 135 STD

Patient AJ Central K’s: 7.44 x 8.10 5mm K’s: 6.50 x 8.50 BC Calculator Lens: 8.40 14.50 Plano STD Feedback: Mo: 0.50mm Ro: 12˚stable – upward and forward C: Good Co: Discomfort superiorly VA Clearer after blink New Trial: 8.80 15.00 Plano STD:STP2 (Inferior portion still 8.40 due to STP2 – majority of lens flattened) Mo: 2mm Ro: 5˚ unstable C: Good Co: Good VA No Fluctuation 6/7.5 ( -9.25 -4.75 x 65 ) Powered Lens: 8.80 15.00 -8.25 -3.75 x 65 STD:STP2