1. The Orthokeratolgy Company
GOV & VIPOK Updates

2. The Ideal Patient

3. The Ideal Ortho-K Patient
Suitable candidates for Ortho-K
Age of Patient – older than 6 years
Spherical refractive power +5D to D
Cylindrical refractive power:
-1.50D or less W-T-Rule astigmatism
-0.75D or less A-T-Rule astigmatism
Children with progressive myopia
Patients free of corneal pathology
Patients that are committed to initial and ongoing cost of treatment

4. Screen for a healthy cornea
Don’t fit when:
Cornea is distorted
Eye Rubbing (treat allergies & habit)
Soft or RGP imprints (allow rehabilitation)
Corneal abnormalities
Irregular corneal astigmatism
Keratoconus
Pellucid Marginal Degeneration
Lid or corneal pathology is present

5. Calibrate Topographer!

6. Topographer Accuracy depends on:
Software algorithms used to reconstruct corneal shape (update software)
Stability of the patient’s tear film during capture (use wetting drops)
Head position & movement during capture
Lid aperture (open eyes)
Number of reading done to get statistically significant accuracy
Take multiple readings
Omit high & low values

7. Cylinder Rules <1.50D W-T-R <0.75D A-T-R Cyl ≤ ½Sph
-0.50 / – Problem
-3.00/-1.00 – Fine

8. Fitting the Ortho-K Lens

9. Empirical fitting vs. Systemised Fitting Systems

10. Empirical Fitting Systems
Corneal information is given to lab
Lab designs lens
Lens works
Or it doesn’t!

11. Systemised Fitting Systems
General fitting process:
Initial lens is chosen from chart
Fit with diagnostic trial lenses and evaluate NaFL pattern – Look for Bull’s eye pattern
Initial lens should not be too flat and should move 1 – 2mm on blink
Evaluate after 30 min using the topographer
Does the Px show a central flattening effect ?

12. Systemised Fitting Systems
General fitting process
If diagnostic lens looks acceptable, allow Px to wear overnight and evaluate the next morning
If the lens is too tight or too loose a different lens can be chosen from trial set and refitted

13. Systemised Fitting Systems
Lens adaptation and follow-up
Centration is critical.
Movement: 1 – 2 mm with blinking.
Flourescein pattern: Bulls eye pattern.

14. Fitting the Ortho-K Lens
Flourescein patterns:

15. The Orthokeratology Company
GOV – Global Ortho-K Vision
Vipok II – Non Conformed <-5.00D
XMJ– Conformed <-5.00D
XM – Conformed >5.00 <10.00D
H – Hyperopia
HP – Hyperopia Presbyopia
MP – Miopic Presbyopia
Post Lasik & Keratoconus
Website (Plan Date Jan 2008)
Ordering
Blog
Px & Prac Education

16. The GOV System Advanced inventory system
Multi-curve aspheric conformed Reverse Geometry Lenses
Simple method for myopia & hyperopia correction
You are in control of the lens fit – not laboratories
Correct from +5.00D to D
GOAL
A simple method to start Orthokeratology allowing for growth into fitting higher powers with the confidence that there is a support group.

17. Benifits Simple effective system
You choose the appropriate lens and make changes
Immediate dispensing – (full trial set)
Efficient and effective method to increase turnover
Develop a specialty Ortho-k practice
Confidently fit with GOV support

18. GOVTM lens details Base curve
Hydraulic massage to central cornea
Conformed fitting curve (1st reverse zone)
Space for tear circulation & tissue molding
Alignment curve (2nd reverse)
Peripheral compression & centration
Peripheral curve
Tear reservoir for cornea wetting

19. Predetermined OAD (lens size)
OADs of trial lenses are predetermined
Flatter Ks accompany larger corneas
Steeper Ks accompany smaller corneas
KM range
OAD
% of HVID
Best-fit HVID
40.00 ~ 42.25
11.2 mm
96%
11.3~11.9 mm
42.50 ~ 43.75
10.8 mm
94%
11.2~11.6 mm
44.00 ~ 47.50
10.4 mm
93%
10.8~11.4 mm

20. Fitting GOVTM Lenses External ocular exam
Measure refraction, keratometry & HVID
Select K-code by Mean K
Select Power-code by S.E.
Order lenses Empirically and/or with trial fit
K-code / Power-code / Color / Material / OAD
Lens size
Predetermined
Match Corneal size by Best-fit HVID

21. Orthokeratology The GOV System K-code: Mean K = (Steep K + Flat K) / 2
Carry value up to 2 decimal places (0.01)
Km in Diopters
Power Calculation:
SE = Spherical Spec power – [K astigmatism / 2]
Spherical power must not be vertexed
K astigmatism = steep K – flat K (in Dioptres)

22. OAD 11.2 mm Best fit cornea 11.3~11.9 mm (OAD=95-97% of HVID)
Mean K/ S.E
OAD 11.2 mm Best fit cornea 11.3~11.9 mm (OAD=95-97% of HVID)
A 39.87~40.11 (40.00)
40.00/-1.5
40.00/-2.0
40.00/-2.5
40.00/-3.0
40.00/-3.5
40.00/-4.0
40.00/-4.5
40.00/-5.0
B 40.12~40.36 (40.25)
40.25/-1.5
40.25/-2.0
40.25/-2.5
40.25/-3.0
40.25/-3.5
40.25/-4.0
40.25/-4.5
40.25/-5.0
C 40.37~40.66 (40.50)
40.50/-1.5
40.50/-2.0
40.50/-2.5
40.50/-3.0
40.50/-3.5
40.50/-4.0
40.50/-4.5
40.50/-5.0
D 40.67~40.86 (40.75)
40.75/-1.5
40.75/-2.0
40.75/-2.5
40.75/-3.0
40.75/-3.5
40.75/-4.0
40.75/-4.5
40.75/-5.0
E 40.87~41.11 (41.00)
41.00/-1.5
41.00/-2.0
41.00/-2.5
41.00/-3.0
41.00/-3.5
41.00/-4.0
41.00/-4.5
41.00/-5.0
F 41.12~41.36 (41.25)
41.25/-1.5
41.25/-2.0
41.25/-2.5
41.25/-3.0
41.25/-3.5
41.25/-4.0
41.25/-4.5
41.25/-5.0
G 41.37~41.66 (41.50)
41.50/-1.5
41.50/-2.0
41.50/-2.5
41.50/-3.0
41.50/-3.5
41.50/-4.0
41.50/-4.5
41.50/-5.0
H 41.67~41.86 (41.75)
41.75/-1.5
41.75/-2.0
41.75/-2.5
41.75/-3.0
41.75/-3.5
41.75/-4.0
41.75/-4.5
41.75/-5.0
I 41.87~42.11 (42.00)
42.00/-1.5
42.00/-2.0
42.00/-2.5
42.00/-3.0
42.00/-3.5
42.00/-4.0
42.00/-4.5
42.00/-5.0
J 42.12~42.36 (42.25)
42.25/-1.5
42.25/-2.0
42.25/-2.5
42.25/-3.0
42.25/-3.5
42.25/-4.0
42.25/-4.5
42.25/-5.0
OAD 10.8 mm Best fit cornea: 11.2~11.6 mm (OAD=93-95% of HVID)
K 42.37~42.66 (42.50)
42.50/-1.5
42.50/-2.0
42.50/-2.5
42.50/-3.0
42.50/-3.5
42.50/-4.0
42.50/-4.5
42.50/-5.0
L 42.67~42.86 (42.75)
42.75/-1.5
42.75/-2.0
42.75/-2.5
42.75/-3.0
42.75/-3.5
42.75/-4.0
42.75/-4.5
42.75/-5.0
M 42.87~43.11 (43.00)
43.00/-1.5
43.00/-2.0
43.00/-2.5
43.00/-3.0
43.00/-3.5
43.00/-4.0
43.00/-4.5
43.00/-5.0
N 43.12~43.36 (43.25)
43.25/-1.5
43.25/-2.0
43.25/-2.5
43.25/-3.0
43.25/-3.5
43.25/-4.0
43.25/-4.5
43.25/-5.0
O 43.37~43.66 (43.50)
43.50/-1.5
43.50/-2.0
43.50/-2.5
43.50/-3.0
43.50/-3.5
43.50/-4.0
43.50/-4.5
43.50/-5.0
P 43.67~43.86 (43.75)
43.75/-1.5
43.75/-2.0
43.75/-2.5
43.75/-3.0
43.75/-3.5
43.75/-4.0
43.75/-4.5
43.75/-5.0
OAD 10.4 mm Best fit cornea: 10.8~11.4 mm (OAD=92-94% of HVID)
Q 43.87~44.11 (44.00)
44.00/-1.5
44.00/-2.0
44.00/-2.5
44.00/-3.0
44.00/-3.5
44.00/-4.0
44.00/-4.5
44.00/-5.0
R 44.12~44.36 (44.25)
44.25/-1.5
44.25/-2.0
44.25/-2.5
44.25/-3.0
44.25/-3.5
44.25/-4.0
44.25/-4.5
44.25/-5.0
S 44.37~44.66 (44.50)
44.50/-1.5
44.50/-2.0
44.50/-2.5
44.50/-3.0
44.50/-3.5
44.50/-4.0
44.50/-4.5
44.50/-5.0
T 44.67~44.86 (44.75)
44.75/-1.5
44.75/-2.0
44.75/-2.5
44.75/-3.0
44.75/-3.5
44.75/-4.0
44.75/-4.5
44.75/-5.0
U 44.87~45.11 (45.00)
45.00/-1.5
45.00/-2.0
45.00/-2.5
45.00/-3.0
45.00/-3.5
45.00/-4.0
45.00/-4.5
45.00/-5.0
V 45.12~45.36 (45.25)
45.25/-1.5
45.25/-2.0
45.25/-2.5
45.25/-3.0
45.25/-3.5
45.25/-4.0
45.25/-4.5
45.25/-5.0
W 45.37~45.66 (45.50)
45.50/-1.5
45.50/-2.0
45.50/-2.5
45.50/-3.0
45.50/-3.5
45.50/-4.0
45.50/-4.5
45.50/-5.0
X 45.67~45.86 (45.75)
45.75/-1.5
45.75/-2.0
45.75/-2.5
45.75/-3.0
45.75/-3.5
45.75/-4.0
45.75/-4.5
45.75/-5.0
Y 45.87~46.11 (46.00)
46.00/-1.5
46.00/-2.0
46.00/-2.5
46.00/-3.0
46.00/-3.5
46.00/-4.0
46.00/-4.5
46.00/-5.0
Z 46.12~46.36 (46.25)
46.25/-1.5
46.25/-2.0
46.25/-2.5
46.25/-3.0
46.25/-3.5
46.25/-4.0
46.25/-4.5
46.25/-5.0
ZA 46.37~46.66 (46.50)
46.50/-1.5
46.50/-2.0
46.50/-2.5
46.50/-3.0
46.50/-3.5
46.50/-4.0
46.50/-4.5
46.50/-5.0
ZB 46.67~46.86 (46.75)
46.75/-1.5
46.75/-2.0
46.75/-2.5
46.75/-3.0
46.75/-3.5
46.75/-4.0
46.75/-4.5
46.75/-5.0
ZC 46.87~47.11 (47.00)
47.00/-1.5
47.00/-2.0
47.00/-2.5
47.00/-3.0
47.00/-3.5
47.00/-4.0
47.00/-4.5
47.00/-5.0
ZD 47.12~47.36 (47.25)
47.25/-1.5
47.25/-2.0
47.25/-2.5
47.25/-3.0
47.25/-3.5
47.25/-4.0
47.25/-4.5
47.25/-5.0
ZE 47.37~47.66 (47.50)
47.50/-1.5
47.50/-2.0
47.50/-2.5
47.50/-3.0
47.50/-3.5
47.50/-4.0
47.50/-4.5
47.50/-5.0
Trial set

23. Prescribe Empirically
Km: x @ 90
RX: x 180
Determine K-code
Mean K=( ) / 2 = 43.81
K-code = 43.75
Determine Power-code
S.E.= – [( ) / 2] = -4.44
Power-code= -4.50
Empirically ordered by
XMJ / (43.75) / / 10.8 mm

24. Empirically with trial fit
Prescribe a looser lens empirically
Subtract 0.50D from K code (flatter K code)
Add D to power-code (less minus)
Order lens by: XMJ / (43.25) / / 10.8 mm
Prescribe a tighter lens empirically
Add 0.50 D to K code (steeper K code)
Add D to power code (more minus)
Order lens by: XMJ / (44.25) / / 10.4 mm

25. Prescribe by over refract trial lens
Select first trial lens by mean K
XMJ/(43.75)/-3.00, if fit is loose
try XMJ/(44.25)/ to tighten AC
Over refraction of XMJ/(44.25)/-3.00 = –1.50 D
Power-code = (-1.50) = -4.50
Order M4 lens by:
XMJ/(44.25)/-4.50/10.4 mm
(Predetermined OAD)

26. As simple as 1-2-3 Select K-code Determine Power-code
Verify OAD (Lens size)

27. The Aligned Fit

28. Aligned Fit
Good compression
Good Seal off
Good Seal off

29. Trouble Shooting
Ideal fit

30. Trouble Shooting
Bull’s Eye Pattern

31. Trouble Shooting
Alignment Fit

32. Too Steep Fit

33. Alignment Fit

34. Steep Fit
No Compression

35. Flatten alignment curve
Up the column

36. Steep Fit
4 Steps

37. Steep Fit
Steep fit – 6 Steps

38. Trouble Shooting
Central Islands

39. Steep Fit
No Compression

40. Central Island
Small areas of distortion along or near the visual axis

41. Central Island Cause: Alignment curve too tight
Excessive uncorrected astigmatism resulting in unequal forces on the cornea
Solution:
Decrease sagittal depth of lens by flattening alignment curve
move up the column
Decentered lens must be centered
Flatten the BC if caused by uncorrected astigmatism
move one column right.

42. Too Flat Fit

43. Alignment Fit

44. Flat Fit Too much bearing Sideway force induced Poor Seal off

45. Flat Fit Decentred Good compression Poor compression Good Seal off
Poor Seal off

46. Steepen alignment curve
Down the column

47. Trouble Shooting
Flat Fit – 4 Steps

48. Trouble Shooting
Smiley Face

49. Flat Fit Decentred Good compression Poor seal off Good Seal off

50. Flat Fit
Smiley Face
Flat fitting lens decentered superiorly

51. Flat Fit Cause: Alignment curve too loose Solution:
Smiley Face
Cause:
Alignment curve too loose
Solution:
Increase sagittal depth of lens by steepening alignment curve
move down the column

52. Lens Fitting
Loose 1.0 D
Loose 0.50 D
Optimal
Tight 0.50 D
Tight 1.0 D

53. Verifying tightness Tight 4 steps Properly fitted Loose 2 steps Loose

54. Power Changes

55. Power Changes

56. Power Changes
Moving Right = More myopia reduction

57. Power Changes
Moving Left = Less myopia reduction

58. Size Matters !

59. Estimate lens size
Obtain white to white corneal Diameter by Topography
Verify Visible Iris Diameter (VID), horizontal & vertically manually
Compare VID to Best-fit VID of the K-code
If VID too large (larger cornea, smaller lens)
Loose fit, Decentration, Poor effect
If VID too small (smaller cornea, larger lens)
Tight fit, Lens Bridging, Central island

60. Standard lens sizes Default OAD based on KM KM ranges
40.00 ~ mm
42.50 ~ mm
44.00 ~ mm

61. Big Corneas KM =< (flatter) 42.25D KM between 42.50 – 43.75D
Rule of thumb:
KM =< (flatter) 42.25D
95% to 97% coverage of VID
KM between – 43.75D
93% to 95% coverage of VID
KM => (steeper) 44.00D
92% to 94% coverage of VID
93% - 95% coverage of VID would suit most corneas most of the time.

62. Big Corneas Use existing trial lenses to evaluate alignment curves
Determine lens Diameter (OAD)
93% of VID if KM =>44.00
94% of VID if KM
96% of VID if KM =<42.25
It is NOT necessary to alter K-kode (alignment) when adjusting for OAD
In high minus lenses (±40% of cases) a flatter alignment lens will be need later on

63. Big Corneas Example: V (45.25D) Lens best fit. VID: 12mm
93% VID coverage = 11.2mm
94% VID coverage = 11.4mm
96% VID coverage = 11.6mm
V lens (KM steeper than 44.00D) = 11.2mm

64. Big Corneas Example how to order: V Lens best fit. VID: 12mm
V lens (KM steeper than 44.00D) = 11.2mm
Eg. 2V04, 11.20mm or XMJ/45.25/-3.00/11.2mm

65. Lens Size 86% too small 89% too small 95% Optimal 98% slightly large
這張圖片，比較鬆緊不同的配鏡狀態，提供給各位醫師做鏡片選擇時的參考。
95% Optimal
98% slightly large
105% very large

66. Case 1 – Big Cornea

67. Case 1 – Big Cornea Male, Age 21 RIGHT LEFT KM= 41.72 = H (41.75)
SE= -1.50D = 01 (-1.50)
Trial 2H01, 10.4mm or XMJ/41.75/-1.50/10.4mm
LEFT
KM= = G (41.50)
Trial = 2G01, 10.4mm or XMJ/41.50/-1.50/10.4mm

68. Case 1 – Big Cornea

69. Case 1 – Big Cornea (Small lens)

70. Case 1 – Big Cornea HVID = 12.9 KM > 42.25D Rule
95% of 12.9 = 12.25mm
Final lens ordered:
R: 2H01, 12.2mm
L: 2G01, 12.2mm

71. Case 1 – Big Cornea

72. Thank you For more information please e-mail met at: