4F Design

A high quality RGP lens for daily wear.

 

This popular RGP lens is available in a selection of materials, with a power range of -40.00D to +40.00D

Features

  • Balanced periphery
  • Optimum edge lift throughout range of parameters

Benefits

  • Available in a range of fluorocarbon materials
  • Choice of material colours
  • Comprehensive range of lens dimensions
   
Material contamac_400 f2_low_400Foccon III 2
Refractive Index 1.460
Permeability (Dk) 28 x 10-11
Wetting Angle 19o
Tints Blue
Grey
Green
Clear
Material  f2_mid_400 Focon III 3
Refaractive Index 1.450
Permeability (Dk) 50 x 10 -11
Wetting Angle 19o
Tints Blue
Grey
Green
Clear
Material  f2_high_400Focon III 4
Refractive Index 1.440
Permeability (Dk) 100 x 10-11
Wetting Angle 21o
Tints
Blue
Green
Clear
Base Curve (mm) 7.05, 7.12, 7.20, 7.27
7.35, 7.42, 7.50, 7.57
7.65, 7.72, 7.80, 7.87
7.95, 8.02, 8.10, 8.17
8.25, 8.32, 8.40, 8.47
Diameter (mm) 8.60, 900, 9.40
9.80, 10.20, 10.60
Power Range -40.00 to +40.00D
(0.25 steps)

 

  • Full refraction and eye examination
  • Keratometry readings
  • For a spherical / near spherical cornea fot on flattest 'k'
    Adjustments should be made according to toricity of the cornea
  • Power shoud be ordered as Best Vision Sphere, making necessary adjustments if lens has been steepend / flattened in relation to flattest 'K'
  • Instil fluorescein to check fitting 

 

Alignment / Good Fit

  • Central position - lens periphery should not extend beyond limbal area
  • Smooth movement - lid lifts lens with blink, lens then falls slowly
  • Good vision
  • Central and mid-peripheral alignment
  • Good edge clearance (approx 0.40mm wide) 
4f_top_400

Loose / Flat Fit

  • Excessive and rapid movement upon blink
  • Arcuate dropping between blinks
  • Lens is unstable and decentrates
  • If lens drops may show inferior arcuate pooling
  • Central touch can be observed
  • Excessive edge clearance
  • May produce a +ve over-refraction
  • Order steeper base curve
4f_middle_400

Tight / Steep Fit

  • Central position
  • Little movement with blink
  • Central pooling
  • Mid-peripheral touch
  • Thin band of edge clearance
  • Mat produce a -ve over-refraction
  • Order flatter base curve
4f_bottom_400

There are 2 fittings set available*

12 lens set

Material Base Curve Range Diameter Power
RGP Only 7.35 to 8.17  9.40 -3.00

20 Lens set

Material Base Curve Range Diameter Power
RGP Only 7.05 to 8.47  9.40 -3.00

* 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.