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