2. MAKE SENSE OF KERATOCONUS

3. 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.

4. 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.

5. MAKE SENSE OF KERATOCONUS
PARAMETER RANGE
FITTING SET PARAMETERS
Base Curve
Diameter
Sphere
Cyl
Axis
Peripheries
SMC
7.40 TO 9.40 mm mm
+/ DS
-0.50 to 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 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.

6. 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.

7. 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

8. 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.

9. FIRST CHOICE LENS

10. 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

11. 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

12. 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

13. FITTING GUIDANCE

14. FITTING GUIDANCE FIRST CHOICE LENS
USE 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

15. 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

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

17. 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 degrees indicates a poor fit

18. 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.

19. 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 keeping Base Curve the same.
Only look at periphery changes if this does not work.

20. FITTING GUIDANCE DIAMETER & PERIPHERY CHANGES WHEN TO CHANGE DIAMETER
Low cones/Post grafts
Always start with Base Curve Calculator and diameter
If lens drops excessively on upward gaze but VA is generally acceptable, move to 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

21. 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

22. 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
Final lens – 7.80:14.50:FLT3
Actual lens 8.60:15.00

23. 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 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

24. 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 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.

25. 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: /-1.00 x 95 STD

26. 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: /-1.75 x 135 STD

27. Patient AJ Central K’s: 7.44 x 8.10 5mm K’s: 6.50 x 8.50
BC Calculator Lens: Plano STD
Feedback:
Mo: 0.50mm
Ro: 12˚stable – upward and forward
C: Good
Co: Discomfort superiorly
VA Clearer after blink
New Trial: 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 ( x 65 )
Powered Lens: x 65 STD:STP2