HydroCone

The HydroCone are a custom made soft keratoconus contact lenses with an unique design. The patented dynamic stabilization retain the same oxygen supply at the limbus comparing a standard  prismatic contact lens. This soft keratoconus contact lenses are available as a single vision, but also in a multifocal version. Depending on the stage of the keratoconus, the HydroCone is available for early and advance stage keratocone. The design provides the patients with comfort as a standard soft contact lens and visual acuity similar to rigid lenses.

Description

Geometry

HydroCone design
  • Spherical back optic zone with strong aspheric flattening
  • Front toric optic zone
  • Dynamic stabilisation with bumps nasal and temporal (Ext Dyn)
  • Optimised centre thickness
  • Marking at 0° and 180°

Variations

HydroCone 12: keratoconus of degrees 1 to 2

HydroCone 34: keratoconus of degrees 3 to 4

HydroCone P:Multifocal-variants of HydroCone 12 and 34 with front optic zone in Bifocal (Bf) /  Simple progressive (Sp) /  Multi progressive (Mp)

Materials

Technical Data

Parameterfromtosteps
Total diameter12.00 mm15.00 mm0.01 mm
Base curve7.00 mm12.00 mm0.01 mm
Sphere-40.00 dpt+40.00 dpt0.01 dpt
Cylinder-0.25 dpt-8.00 dpt0.01 dpt
Axe180°
Addition+0.50 dpt+4.00 dpt0.01 dpt
Central optical zone Zoc1.00 mm5.50 mm0.01 mm
Flattening(+) K12(++) K34

Additional information

Application

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Indication

Correction type

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Lens Type

Designed by

SwissLens

Fitting advices for ToriFlex

Fitting advices

We suggest working with trial lenses with cyl −0.01 dpt.

Keratoconus classification

First apply the topographic indications or the following rules:

  • Vcc > 0.6 and/or keratometry > 6.80 mm: grade 1 or 2 (HydroCone K12)
  • Vcc < 0.6 and/or keratometry < 6.80 mm: grade 3 or 4 (HydroCone K34)
Diameter and base curve: 1st trial lens
  • HydroCone K12: BC = 8.00 / ØT = 14.00 mm
  • HydroCone K34: BC = 7.80 / ØT = 13.70 mm
Advice
  • The first trial lens helps to validate BC / ØT.
  • Dynamic stabilisation marks are needed to measure the stabilisation axis
  • The power (F’v) is spherical because part of the correction is made by the tear film and can’t be anticipated. The final cylinder corresponds to the residual astigmatism.
  • F’v for the trial lens order: spectacle sphere (adjust BVD = 0) with −0.01 dpt × 180° cylinder
  • For changes and control over several months always use the initial (genesis) lens for over refraction.
  • Use upper and lower eyelids to remove the contact lens.
  • By halo, increase optic zone diameter
  • Measurement of the residual astigmatism with autorefractometer plus subjective refractometry.
  • Due to geometry, the contact lens can slip a little bit to the bottom.
  • Increasing centre thickness can improve the visual acuity.
  • HydroCone P fitting: initially fit with HydroCone (single vision toric lens) then add progression in a second step BC

First contact lens choice

Progression system and central optic zone (Zoc)

Reading zone choice
  1. Centre near vision in most cases
  2. Peripheral near vision if distance vision is poor, high myopia or decentrated pupil.

Procedure

  • Determine dominant eye
  • Find maximum convex (+) correction for distance vision
  • Find the best acuity in distance vision to optimise Zoc diameter choice
  • Determine the patients needs for: distance / intermediate / near Multifocal design choice

Multifocal design choice

RequirementsBifocal BfSimple progressive SpMulti progressive Mp
Hyperopia
Myopia Addition < 1.75 dpt
Myopia: Addition ≥ 1.75 dpt
Priority in distance vision
Priority in near vision
Priority in intermediate vision (computer)
Use in low light in distance vision
Use in low light in near vision
Good contrast
Low Helos
Anisometropia > 2.00 dpt
Amblyopia ( √ )
Modified monovision care ( √ )

Central optic zone, position and diameter:

recommendations for the 1st choice: standard pupil (3.50–4.00 mm) with normal lighting

Bifocal BfBifocal BfSimple progressive SpSimple progressive SpMulti progressive Mp
PositionCentre near (CN)Centre Distance (CD)Centre near (CN)Centre Distance (CD)Centre near (CN)
Dominant eye2.253.752.504.001.50
Non-dominant eye2.753.253.003.501.75
Undefined2.503.502.753.751.50

For non standard pupil size or for distance/near preference, fit the Zoc in steps of 0.25 mm

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