Table 1.

The fitting set parameters and the fitting assessment procedure of Toris K.

Technical data	Values
Total diameter	13.70 mm (HydroCone K12)
	14.00 mm (HydroCone K34)
Base curve	7.20 to 8.40 D
Sphere	−40.0 to +40.0 D
Cylinder	−0.01 to −8.00 D
Axis	0–180°
Center thickness	Standard K12 = 0.42 mm, K34 = 0.52 mm
	Range of thickness: 0.3520.59 mm
The Fitting Assessment Procedure
First contact lens choice
It is suggested working with trial lenses with cylindrical power −0.01 D
Keratoconus classification
First apply topographical indications or follow the rules:
Vcc > 0.6 and/or keratometry > 6.8: grade 1 or 2 (choose HydroCone K12)
Vcc < 0.6 and/or keratometry < 6.8: grade 3 or 4 (choose HydroCone K34)
Diameter and base curve selection
Add 0.8 diopters to the average K value and then select a trial lens
HydroCone K12/total diameter = 14.00 mm
HydroCone K34/total diameter = 13.70 mm
Further steps
The first lens helps to validate base curve and total diameter
The patient should wait for 30 min
Dynamic stabilization marks should be evaluated to measure the stabilization axis
Push-up test should be done
The fitting curve should demonstrate typical fitting of characteristics of a standard soft lens fit
If the fitting curve is too flat, there will be excessive movement and/or edge lift and then switch to a steeper trial lens
Little or no movement and/or edge impingement would indicate the fitting curve is too steep and then switch to a flatter trial lens
Overrefraction should be done
Prescription should include both spherical and cylindrical errors with its axis
In case of glare and/or halo, you can request to enlarge the optical zone

D: diopter and Vcc: best spectacle corrected visual acuity.