CC & CC Toric
The CC combines the benefit of the clearest vision of a spherical lens and the fitting flexibility of a aspheric lens. The CC is the optimum lens for lens fits up to 9.60mm diameter. The spherical optic provides optimum vision for both centred and decentred lenses, the mid-peripheral fitting helps optimal centration and the aspheric edge aids tear exchange.
Ordering by supplying spectacle Rx, BVD and Ks will generally provide an optimal fitting lens. Trial lens sets are available for spherical BOZR range.
- For new wearers instil anaesthetic to stabilise lens fit and optimise initial patient experience.
- Assess lens fit with fluorescein and yellow filter at slip lamp.
- With toric lenses note flat axis marks (- -) rotation.
In an optimum fit lenses will move post blink vertically. Toric lenses will also appear as pictured. A lens that rides high and does not move with the lid is a high riding fit. This is usually due to lid interaction and corneal shape, altering the lens will not centre high riding lenses. Some lenses will drop and not move, especially high plus powers, reducing the lens diameter 0.5mm will reduce the weight and thickness of the lens. Low riding lens fits can be tolerated, increase the diameter if the pupil is not covered.
Assess the acuity with a distance chart, check the lens power with spherical over refraction. If the lens is a reading lens in monovision note the minus over refraction for optimum distance. With toric lenses align cross-cyl with the rotation of the flat axis marks.
If either the fit or power of the lens need altered forward the information to the lab or specify the parameters for the new lens.
CC Initial Trial Lens Parameters
|0.00 to 1.75 D Cyl
Ks differ up to 0.35rd
|Base Curve 0.1mm steeper than flat K Corneoscleral||Power -0.50 more than spec Rx sphere|
| Over 2.00 D Cyl
Ks differ 0.40 or more
|KFLAT BOZR -0.05mm
KSTEEP BOZR +0.05mm
|PowerFLAT -0.25 more than spec Rx
PowerSTEEP +0.25 more than spec
Spectacle Rx should be minus cyl form. Correct for BVD is spec Rx is over +4.50.
CC Features & Benefits
|Spherical BOZR zone||Predictable empirical fitting||Reduced chair time, satisfied patients|
|Even tear layer when decentred||Quality acuity even in non-optimal fits|
|Aspheric periphery||Seamless transition from optic to edge||Simplifies assessment, improves tear pump affect|
|Lathe2i freeform manufacture||Optimum surface quality and parameter accuracy||Improves comfort and surface quality. Ensures repeatability|
|Optimised thickness profile||Minimised lens weight, minimises lid interaction||Improves comfort and vision|
|Unrestricted material selection||Optimised performance for patient needs||Improves surface quality and patient biocompatibility|
Download this page in PDF format.