Nissel KII Rigid

RGP lens for successful management of Keratoconus


A highly successful aberration controlled RGP lens for the management of Keratoconus.  The availability of a single use trial set helps to reduce chair time.


  • System of management for Keratoconus in modern hospital and specialist clinic environments
  • Single use trial lenses
  • Diagnostic set sucessfully fits approx. 80% of Keratoconic patients


  • No-cost replacement trials
  • Unique adaptive back surface geometry
  • Aberration control optics provide best visual acuity in all lighting levels
Material contamac_400 optimum_comfort_400 Focon III 3
Permeability (Dk) 65 x 10 -11
Base Curve (mm) Steepest available 4.80
Diameter (mm) 8.10, 8.40
(standard) 8.70
9.00, 9.30
Edge Lift
(0.03mm = 1 step) 
Increased 1 Step
Increased 2 Step
Decreased 1 Step
Decreased 2 Step
Power Range -30.00 to +30.00 (0.25D steps)
Material Colour (Standard) Blue


  • Full refraction and eye examination
  • Keratometry / Topography
  • From the 8.70mm diameter fitting set select the lens having a base curve 0.30mm steeper than average 'K' / Flat Sim 'K' or closest lens to this value 



Good Fit

  • Central position
  • Small amount of apical clearance or very light apical touch
  • Good edge clearance - 0.50 to 0.80mm
  • Smooth movement - lid lifts lens with blink, lens then falls slowly


  Acceptable fit showing minimal apical clearance


  Acceptable fit showing light apical (3-point) touch

Central Fit Assessment

  • Steep Lens - Excessive apical clearance - may reduce visual acuity - try flatter base curve
  • Flat Lens - Large area of central touch - try steeper base curve until only light touch is seen


  Steep Fit


  Flat Fit

Edge Clearance Assessment

  • Excessive Edge Clearance - wider than 0.80mm - lens will have excessive movement - decrease edge lift
  • Inadequate Edge Clearance - less than 0.50mm - lens may have reduced movement - dark ring of peripheral touch will be evident - increase edge lift


  Good apical fit, but excessive edge clearance

Lens Location

  • If lens riding low - increase the total diameter
  • If lens riding high - decrease total diameter
Over-refration should be carried out and final lens ordered from Cantor & Nissel

A 26 Rigid KII lens fitting set is available*

Material Base Curve Range Diameter Range Power
RGP  4.90 to 7.40 8.70 Stock

* A registered account with Cantor & Nissel is required.

Optician looking to order? Call us on +44 (0)1280 702002

Register with Cantor and Nissel for our online ordering facility and be able to order the following lenses via our website: Cantor Prosthetic, Hydrocyl, Hydrofit, Hydrolens and Nissel Custom Hand Painted. The online forms with their drop down menus allow you to order lenses without the need to refer to any size or colour charts.