Article

Soft Contact Lenses

Hydrogel and Silicone Hydrogel Lens General Considerations

Soft Contact Lenses

Hydrogel and Silicone Hydrogel Lens General Considerations

The FDA gives each contact lens material a generic name. In general, all hydrogel and silicone hydrogel lens generic names end in the suffix “filcon” and all nonhydrogel lenses end in “focon.”

Hydrogel lenses are categorized into four groupings for purposes of evaluating effects of accessory products upon the lens material. Lenses with less than 50 percent water content are considered to be “low water” and the others are “high water.” Less reactive surfaces are termed “nonionic” and more reactive materials are labeled “ionic.” Silicone hydrogel lenses are low water.

Disinfection of hydrogel and silicone hydrogel lenses can usually be done safely and effectively by approved chemical or hydrogen peroxide systems. However, some Group 4 ionic polymers may react negatively with potassium sorbate- or sorbic acid-preserved solutions.

In the term Dk, D stands for diffusion and k for solubility. The oxygen permeability of hydrogel lenses is almost entirely the result of solubility and for GP materials almost entirely the result of diffusion. In silicone hydrogel materials, oxygen permeability is a combination of solubility and diffusion, with the larger amount from diffusion. That is, the hydrogel component in the formulation provides solubility and the silicone component provides diffusion. Each generic material below is accompanied by a representative Dk number.

A clinically useful approximation is to consider Dk values for hydrogel lenses in three groups:

H20 Dk
38±%
55±% 18±
75±% 36±

It is also important to remember that Dk/t (central transmissibility) and Dk/t (average overall transmissibility) are dependent upon contact lens thickness configuration and are more important than Dk with hydrogel lenses. With silicone hydrogel contact lenses, Dk/t and Dk/t are more similar than with hydrogel lenses.

This table should assist you in identifying specific lenses in each category as related to disinfection and Dk; and it will also help you determine an appropriate mix of lens types for your practice.

GROUP 1

Low Water (<50% H20)
Nonionic Hydrogel Polymers

tefilcon (38%) (Dk = 8.9)

  • Cibasoft
  • Illusions
  • Softint
  • STD
  • Torisoft
  • LL Bifocal

tetrafilcon A (43%) (Dk = 9)

  • Cooper Clear
  • Cooper Toric
  • Preference
  • Preference Toric
  • Vantage Thin Accents
  • Vantage
  • Vantage Accents
  • Vantage Thin

crofilcon (38%) (Dk = 13)

  • CSI
  • CSI Toric

helfilcon A&B (45%) (Dk = 12)

  • Continental Toric
  • Flexlens
  • Flexlens Toric
  • Flexlens Aphakic
  • Optima Toric

mafilcon (33%) (Dk = 4)

  • Menicon

polymacon (38%) (Dk = 9)

  • Allvue
  • Biomedics 38
  • Clearview
  • CustomEyes 38
  • EpconSOFT
  • EsstechPS
  • Esstech PSD
  • Esstech SV
  • Frequency 38
  • HD
  • HD-T
  • HDX
  • HDX-T
  • Horizon 38
  • Hydron Mini
  • Hydron Zero 4 SofBlue
  • Hydron Zero 6 SofBlue
  • Hydron Versa Scribe
  • Lifestyle MV2
  • Ideal Soft
  • Lifestyle Xtra
  • Lifestyle 4Vue
  • Lifestyle Toric Bifocal
  • LL38
  • Metrosoft ll Multifocal
  • Metrosoft Toric
  • Natural Touch
  • Occasions
  • Optima 38
  • PS-45 Multifocal
  • Simulvue 38
  • Sof-form II
  • Soflens
  • Soflens 38
  • Soflens Multifocal
  • Softics
  • SoftView
  • Unilens 38
  • Westhin Toric
  • hioxifilcon B (49%) (Dk = 15)

    • Alden HP
    • Alden HP Toric
    • Aquaease
    • Essential Soft Toric Multifocal
    • Flexlens
    • Quattro
    • Satureyes
    • Satureyes Toric and Multifocal

    Note: All X-Cel lenses are available in helfilcon A, hioxifilcon A, hioxifilcon B, and methafilcon A.

    Silicone Hydrogel Polymers

    lotrafilcon A (24%) (Dk = 140)

    • Air Optix Night & Day Aqua

    lotrafilcon B (33%) (Dk = 110)

    • 020ptix
    • Air Optix for Astigmatism
    • Air Optix Aqua Multifocal
    • Air Optix Aqua

    galyfilcon A (47%) (Dk = 60)

    • Acuvue Advance
    • Acuvue Advance for Astigmatism

    narafilcon B (48%) (Dk = 55)

    • 1-Day Acuvue TruEye

    senofilcon A (38%) (Dk = 103)

    • Acuvue Oasys
    • Acuvue Oasys for Astigmatism
    • Acuvue Oasys for Presbyopia

    sifilcon A (32%) (Dk = 82)

    • 020ptix Custom

    comfilcon A (48%) (Dk = 128)

    • Biofinity
    • Biofinity Toric

    enfilcon A (46%) (Dk = 100)

    • Avaira
    • Avaira Toric

    GROUP 2

    High Water (>50% H20)
    Nonionic Hydrogel Polymers

    lidofilcon A(70%)(Dk = 31)

    • • Acti Fresh 400
    • •CV 70

    alfafilcon A (66%) (Dk = 32)

    • Soflens Toric

    omafilcon A (59%) (Dk = 33)

    • Biomedics XC
    • Proclear 1-Day
    • Proclear EP
    • Proclear Multifocal
    • Proclear Multifocal Toric
    • Proclear Sphere
    • Proclear Toric

    vasurfilcon A (74%) (Dk = 39.1)

    • Precision UV

    hioxifilcon A (59%) (Dk = 28)

    • Extreme H20 59% Thin
    • Extreme H20 59% Extra
    • Biocurve Gold Sphere and Toric

    hioxifilcon D (54%) (Dk = 21)

    • Clarity H20
    • C-Vue Advanced Custom Toric
    • Extreme H20 54%
    • Extreme H20 54% Toric

    nelfilcon A (69%) (Dk = 26)

    • Dailies AquaComfort Plus
    • Focus Dailies
    • Focus Dailies Toric
    • Focus Dailies Progressive
    • FreshLook One-Day
    • Synergy
    • Triton

    hilafilcon B (59%) (Dk = 22)

    • SofLens Daily Disposable

    acofilconA(58%)Dk = (25.5)

    • Flexlens Tricurve Keratoconus

    GROUP 3

    Low Water (<50% H20)
    Ionic Hydrogel Polymers

    bufilcon A (45%)(Dk = 16)

    • Hydrocurve II 45
    • Soft Mate B

    deltafilcon A (43%)(Dk = 10)

    • Amsoft
    • Amsoft Thin
    • Comfort Flex
    • Custom Flex
    • Metrosoft
    • Soft Form Toric

    phemfilcon A (38%) (Dk = 9)

    • DuraSoft 2
    • DuraSoft 2 Optifit
    Silicone Hydrogel Polymers

    balafilcon A (36%) (Dk = 112)

    • PureVision
    • PureVision Multi-Focal
    • PureVision Toric

    GROUP 4

    High Water (>50% H20)
    Ionic Hydrogel Polymers

    bufilcon A (55%) (Dk = 16)

    • Hydrocurve I
    • Hydrocurve 3 Toric
    • Softmate II

    perfilcon (71%) (Dk = 34)

    • Permalens
    • Permalens XL
    • Permalens Therapeutic
    • Permalens Aphakic

    etafilcon A (58%) (Dk = 28)

    • Acuvue
    • 1-Day Acuvue
    • 1-Day Acuvue Moist
    • Acuvue 2
    • Acuvue 2 Colours
    • Acuvue Bifocal

    focofilcon A (55%) (Dk = 16)

    • Fre-Flex

    ocufilcon B (53%)(Dk = 16)

    • ClearSight 1 Day
    • Continental
    • Ocu-Flex 53

    ocufilcon C(55%)(Dk = 16)

    • UCL55
    • UCL-Pediatric

    ocufilcon D (55%) (Dk = 19.7)

    • Biomedics 55
    • Biomedics 55 Premier
    • Biomedics Toric
    • ClearSight 1 Day Toric

    ocufilcon E (65%) (Dk = 22)

    • Ocuflex 65

    ocufilcon F (60%) (Dk = 24.3)

    • Hydrogenics 60 UV

    phemfilcon A (55%) (Dk = 16)

    • DuraSoft 3
    • DuraSoft 3 Optifit
    • Freshlook
    • Freshlook Toric
    • Freshlook Colorblends
    • Wildeyes

    methafilcon A (55%) (Dk = 18)

    • Biocurve Advanced Aspheric
    • Biocurve 1-Day
    • Biocurve Toric & Sphere
    • C-Vue1 Day ASV
    • C-Vue 55
    • Edge III 55
    • Elite AC
    • Elite Daily
    • Elite AC Toric
    • Flexlens
    • Frequency 55 Sphere & Multifocal
    • HD2
    • HDX2
    • Horizon 55 Bi-Con
    • Kontur
    • LL55
    • New Horizons
    • Sauflon 55 UV
    • Sauflon 55 Asphere
    • Sof-form 55
    • Vertex Sphere
    • Vertex Toric

    methafilcon B (55%) (Dk = 18)

    • Frequency 55 Toric
    • Hydrasoft Sphere
    • Hydrasoft Toric

    vilfilcon A (55%)(Dk = 16)

    • Focus 1-2 Week Softcolors
    • Focus Monthly Softcolors
    • Focus Progressives
    • Soft 55
    • Soft 55 EW

    Spherical Clear and Visibility Tint Disposable and/or Planned Replacement Hydrogels

    Disposable and/or Planned Replacement Tinted Enhancer and Opaque Hydrogels

    Toric Disposable and/or Planned Replacement Hydrogels

    Multifocal Disposable and/or Planned Replacement Hydrogels

    Daily Wear Spherical Clear and Visibility Tint Hydrogels

    Extended Wear Spherical Clear and Visibility Tint Hydrogels

    Therapeutic Spherical Clear and Visibility Tint Hydrogels

    Aphakic Spherical Clear and Visibility Tint Hydrogels

    Special Design Spherical Clear and Visibility Tint Hydrogels

    Daily Wear Tinted Enhancer and Opaque Hydrogels

    Customized Tinting

    Adventures In Color Technology, Alden Optical, Crystal Reflections, Custom Color Contacts, Specialty Tint, and Ciba Vision Special Eyes Program provide custom tinting of soft contact lenses for prosthetic and other uses. For specific information, call them. Their telephone numbers and addresses are listed in the company directory at the end of this booklet.

    Marietta Vision states that the Chromagen lens is available for certain color deficiencies. It has a 5mm to 7mm tinted optic zone and custom parameters. Call (866) 300-6257 for details.

    Extended Wear Tinted Enhancer and Opaque Hydrogels

    Daily Wear Toric Hydrogels

    Extended Wear Toric Hydrogels

    Daily Wear Multifocal Hydrogels

    Extended Wear Multifocal Hydrogels

    Multifocal Toric Hydrogels

    Hybrid Soft Skirt/GP Center