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OK E-System Certification Frequently Asked Questions

The Contex OK® Lens and Bausch & Lomb Vision Shaping Treatment™

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Fits All Types of Keratoconus
• Aspheric Design
• 3 Point Touch Fit

The AS-20H lens utilizes a high eccentricity value. This allows us to fit a
steep base curve so the lens will rest lightly on the cone but it also gives
us a light touch in the periphery to balance the pressures. The first lens
should be fit about five diopters steeper than flat K.

These tips should help you achieve a successful fit:
1. Light touch on cone.
2. The lens should center between the apex of the cornea and the cone.
3. Peripheral clearance is a must to promote tear exchange to the cone.
4. The lens must display adequate movement on the blink.
5. The best starting overall diameters are 10.0 - 10.2mm.
6. Trial fitting is a must for best success.

If Indicated Lens is Too Tight:
Flatten the Base Curve by ½ diopter
If Indicated Lens is Too Loose: Steepen the Base Curve by ½ diopter

CK’s: R: 48.00/52.00
         L: 49.50/53.00
Refraction: -6.00
Refraction: -7.00
Eccentricity Value = .72
Eccentricity Value = .79

R: Base Curve: 6.37
L: Base Curve: 6.19
Lens Power: -10.62 (w/vertex)
Lens Power: -11.50 (w/vertex)

For further fitting details download the AS-20H Fitting and Information Sheet or contact one of our knowledgeable consultants. Download PDF

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