iZySolutions - Documentation

IWICATALOG - Contact lenses: Technical

Owned by AngƩlique ManƩra (Unlicensed)
Last updated: Sept 07, 2020
2 min read

You can use this tab to describe the technical data of a contact lens.

MAIN CHARACTERISTICS

  • Front surface geometry (mandatory): to indicate the geometry of the front surface in EDI catalogs

  • Back surface geometry (mandatory): to indicate the geometry of the back surface in EDI catalogs

  • HEMA (mandatory): to indicate if the contact lens is made from hydroxymethacrylate material which allows to have a higher water content

  • UV blocking (mandatory): to indicate if the contact lens contains a UV filter

  • Geometric center thickness (mandatory): thickness at the center of the smallest circle in which the contact lens fits. The thickness at the center is given for a -3.00 d lens, except special mention

  • FDA group (mandatory) : for hydrogel materials, indicates the classification of hydrogel materials into four categories. Within each category the materials have similar behaviors towards the environment and maintenance solutions. For the adapter, this classification is an assistance in the choice of material according to the constraints of use and the physiological characteristics (quality of tears, lightening...) of the patient's eyes.

  • Handlings tint (mandatory): to indicate if the contact lens contains a handling tint

  • Special grave (mandatory): indicates whether the lens contains engravings to check the centering of a contact lens

Explanatory table for HEMA material

Hydrophilia, Wettability

Low water content < 50%

High water content > 50%.

Hydrophilia, Wettability

Low water content < 50%

High water content > 50%.

Non-ionic

Group 1 - HEMA PHMA

Group 2 - HEMA+GMA or NVP

Pros:Ā 

  • Ease of contact lens handling

  • Low surface deposits

Indication:

  • Bad tears quality (too much lipids)

Cons:

  • Difficulty in handling the contact lenses

Indication:

  • In case of high power in + or -

  • Extended wear

  • Do not prescribe in case of insufficient tears

Ionic

Group 3 - no LRF in this group

Group 4 - PHMA+PVP, HEMA+MA+NVP

Cons:

  • Protein and lipid deposits

Pros:

  • Ease of contact lens handling

Indication:

  • Can be worn in dry atmosphere because of better wettability

Cons:

  • Protein deposits (especially lisozime)

Ā Indication:

  • In case of high power in + or -

  • Extended wear (now preferred with Silicone hydrogels).

  • Avoid oxidizing treatments

SECONDARY CHARACTERISTICS

  • Front central optical zone diameter (optional)

  • Back central optical zone diameter (optional)

  • Oxygen transmissibility (optional): to informs about oxygen permeability (Dk) divided by thickness (e) in centimetres

  • Measurement technique of transmissibility (conditional): must be filled in if Oxygen transmissibility data is given

  • Oxygen permeability (optional): to inform about the transmissibility of oxygen in case of pressure difference across the contact lens material

  • Water content (optional): to provide information on the amount of water (in %) present in a hydrated contact lens

DESCRIPTIONS

  • Delivery ranges (required): to describe the power ranges available on the contact lens. The blue Generate button is used to automatically enter the value. It analyzes all the price grids of the contact lens in order to create the descriptive text taking into account the diameters, radius, spheres, cylinder and additions

  • Special mark (optional): to describe the marking on the contact lens

  • Indications (optional): to describe the indications for contact lens corrections

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