List of soft contact lens materials explained

Soft contact lenses are one of several types of contact lenses for corrective vision eyewear as prescribed by optometrists and ophthalmologists.[1]

Background

In the US market, soft contact lenses are approved by the US Food and Drug Administration.[2] The American Optometric Association published a contact lens comparison chart called Advantages and Disadvantages of Various Types of Contact Lenses on the differences between them.[3] These include:

The US Food and Drug Administration (FDA) defines soft contact lenses as:

History

The first contact lenses were made of glass, in 1888. Initially the glass was blown but soon lenses were made by being ground to shape. For the first fifty years, glass was the only material used. The lenses were thin, yet reports of injury were rare. In 1938 perspex (polymethylmethacrylate, or PMMA) began to replace glass in contact lens manufacture. PMMA lenses were easier to produce so the production of glass lenses soon ended. Lenses made of PMMA are called hard lenses.[4] Soft contact lenses were first produced in 1961 by Czech chemical engineer Otto Wichterle using polyhydroxyethylmethacrylate (pHEMA), a material that achieved long-term commercial application. Lenses made of polyacrylamide were introduced in 1971.

Types

The FDA classifies soft contact lenses into four groups for the US market. They are also subcategorized into 1st generation, 2nd generation, and 3rd generation lens materials.[5] These 'water-loving' soft contact lens materials are categorized as "Conventional Hydrophilic Material Groups ("-filcon"):

Group Water Content Percentage Ionic/Non-Ionic
I Low Water Content (<50%) Nonionic
II High Water Content (>50%) Nonionic
III Low Water Content (<50%) Ionic
IV High Water Content (>50%) Ionic
Note: Being ionic in pH = 6.0 - 8.0".[6] The FDA has been considering updating soft contact lens group types and related guidance literature.[7] [8] [9]

Contact lens polymers

The materials that are classified in the 5 FDA groups include the ones listed in the next 5 sections:[10] [11]

FDA classification of soft contact lens materials[12] !FDA lens group!Adopted name!Transmissibility level(Dkx10)!Water content!Chemical composition
I
galyfilcon A6047%
lotrafilcon A14024%, siloxane,
lotrafilcon B11033%
polymacon7.536%
tetrafilcon9.043.5%,,
II
alphafilcon A22.966%,
hilafilcon A26.970%
omafilcon A19.662%,
III
balafilcon A9936%,,,
bufilcon A16.045%,,
IV
etafilcon A17.058%,
ocufilcon D19.755%
vifilcon A16.055%,, PVP

Hydrogel groups

Below is a list of most contact lens materials on the market, their water percentage, their oxygen permeability rating, and manufacturer brands.[13] [14] [15] [16] Note that the higher the oxygen transmissibility rating, the more oxygen gets to the eye.

Low water nonionic

Material % Water Oxygen Transmissibility (Dk/t) Brands
Tefilcon 38 8.9 Cibasoft, Illusions, Torisoft, Softint, STD, LL Bifocal
43 9 Cooper Clear, Cooper Toric, Preference, Preference Toric, Vantage, Vantage Accents, Vantage Thin, Vantage Thin Accents
38 13 CSI, CSI Toric
Helfilcon A/B 45 12 Continental Toric, Flexlens, Flexlens Toric, Flexlens Aphakic, Optima Toric, All X-Cel lenses
Mafilcon 33 4 Menicon
38.6 8.5-24.3 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/SP, PS-45 Multifocal, Simulvue 38, Sof-form II, SofLens, SofLens38, SofLens Multi-Focal, Softics, SoftView, Unilens 38, Westhin Toric, EZvue Soft Contact Lens, Solotica
49 15 Alden HP Sphere, Alden HP Toric, Aquaease, Essential Soft Toric Multifocal, Flexlens, Quattro, Satureyes, Satureyes Toric and Multifocal, All X-Cel Lenses

High water nonionic

Material % Water Oxygen Transmissibility (Dk/t) Brands
74 35
70 31 ActiFresh 400, CV 70
79 38
65 34.5
Hefilcon B 45 10 Optima Toric
Alphafilcon A 66 32 SofLens Toric for Astigmatism
58-60 28–36.7 Proclear 1-Day, Proclear EP, Proclear 1 day Multifocal, Proclear Multifocal Toric, Biomedics XC, Aveo
Omafilcon B 62 21.3-52.3 Proclear Sphere, Proclear toric, Proclear toric XR, Proclear multifocal, Proclear multifocal XR, Proclear multifocal toric
74 39.1 Precision UV
59 28 Alden HP Sphere, Alden HP Toric, ExtremeH₂O 59% Thin/Extra, Biocurve Gold Sphere and Toric, Aura ADM, Scout by Warby Parker,[17] Hydro by Hubble, Miru 1 Day[18]
54 21 Alden HP Sphere, Alden HP Toric, ExtremeH₂O 54%, Clarity H₂0, C-Vue Advanced Custom Toric
Nelfilcon A 69 26 Focus Dailies, Focus Dailies Toric/Progressive, Dailies AquaComfort Plus, FreshLook One-Day, Synergy, Triton
70 35
59 22 SofLens 59, SofLens Daily Disposable, SofLens Daily Disposables for Astigmatism
Acofilcon A 58 25.5 Flexlens Tricurve Keratoconus
Nesofilcon A 78 42 Biotrue ONEday

Low Water ionic

Material % Water Oxygen Transmissibility (Dk/t) Brands
45 16 Hydrocurve II 45, Soft Mate B
43 10 Amsoft, Amsoft Thin, Comfort Flex, Custom Flex, Metrosoft, Soft Form Toric
38 9 Durasoft 2

High Water ionic

Material % Water Oxygen Transmissibility (Dk/t) Brands
55 16 Hydrocurve I, Hydrocurve 3 Toric, Softmate II
71 34 Permalens
58 23.8-28 Acuvue, Acuvue Bifocal, Acuvue 2, Acuvue 2 Colors, 1-Day Acuvue, 1-Day Acuvue Moist, 1-Day Acuvue Moist for Astigmatism, 1-Day Acuvue Moist Multifocal, 1-Day Acuvue Define, Colornova, Discon, Waldo, Natural Vue, Ocylens
55 16 Fre-Flex
52-53 16-24 ClearSight 1-Day, Continental, Ocu-Flex 53
55 16 UCL55, UCL-Pediatric
55 17.8-28.1 Biomedics 55 Premier asphere, Biomedics Toric, ClearSight 1-Day Toric, Horien 1-Day Disposable
65 22 Ocuflex 65
60 24.3 Hydrogenics 60 UV
55 16 Durasoft 3, Freshlook, Wildeyes
55 17.9-37.6 Biocurve Advanced Aspheric, Biocurve 1-Day, Biocurve Toric & Sphere, C-Vue 1-Day ASV, C-Vue 55, Edge III 55, Elite AC, Elite Daily, Elite AC Toric, Expressions Colors, Flexlens, Frequency 55 Sphere/Multifocal, HD2, HDX2, Horizon 55 Bi-Con, Hubble, Kontur, LL55, New Horizons, Revolution, Sauflon 55, Sof-form 55, Sunsoft Eclipse, Sunsoft Toric, Vertex Sphere, Vertex Toric
55 14.5-31.3 Frequency 55 Toric, Hydrasoft Sphere, Hydrasoft Sphere Thin, Hydrasoft Aphakic, Hydrasoft Aphakic Thin, Hydrasoft Toric, Hydrasoft Toric Thin
55 16 Focus 1-2 Week Softcolors, Focus Monthly Softcolors, Focus Toric, Focus Progressives, Soft 55, Soft 55 EW

Silicone hydrogel polymers

Material FDA Group % Water Oxygen Transmissibility (Dk/t) Modulus (MPa) Center Thickness (mm) Brands
1 24 175[19] 1.5 0.08 Air Optix Night & Day Aqua
1 33 110-138 1.0 0.08 O2Optix, Air Optix for Astigmatism, Air Optix Aqua, Air Optix Aqua Multifocal, Air Optix Colors
1 47 86[20] 0.43 0.07 Acuvue Advance with Hydraclear, Acuvue Advance for Astigmatism
1 38 103-147 0.7 0.07 Acuvue Oasys, Acuvue Oasys for Astigmatism, Acuvue Oasys for Presbyopia, Acuvue Oasys 1-Day, Acuvue Oasys 1-Day for Astigmatism, Acuvue Oasys with Transitions, Acuvue Oasys Max 1-Day, Acuvue Oasys Max 1-Day Multifocal
Senofilcon C 41 129-147 0.77 0.07 Acuvue Vita, Acuvue Vita for Astigmatism
Sifilcon A 1 32 82 0.08 O2Optix Custom
1 48 116-160 0.75 0.08 Biofinity, Biofinity toric, Biofinity XR, Biofinity XR toric, Biofinity Energys, Biofinity multifocal
1 46 100 0.6 0.06 Avaira, Avaira Toric
3 36 91-130 1.1 0.09 PureVision, PureVision Toric, PureVision Multi-Focal, PureVision2, PureVision2 for Astigmatism, PureVision2 Multi-Focal for Presbyopia
Delefilcon A 33-99
(water gradient)
156[21] 0.7 0.09 Dailies Total1, Dailies Total1 Multifocal, DailiesTotal1 for Astigmatism
Narafilcon B 1 48 55 1-Day Acuvue TruEye (old)
Narafilcon A 46 118 0.66 0.085 1-Day Acuvue TruEye (new)
Stenfilcon A 54 80-100 0.4 0.08 MyDay, MyDay toric, MyDay Multifocal, Kirkland Signature
Somofilcon A 56 57-86 0.5 0.07 Clariti 1 day, Clariti 1 day toric, Clariti 1 day multifocal, Live daily disposable
Fanfilcon A 55 90-110 0.6 0.06 Avaira Vitality, Avaira Vitality toric, 24H Toric
46[22] 163[23] 0.7 0.07 Bausch & Lomb Ultra, Bausch & Lomb Ultra for Astigmatism, Bausch & Lomb Ultra for Presbyopia
Elastofilcon 0.2 340 SilSoft Aphakic, SilSoft Super Plus
Kalifilcon A55134[24] 0.5 0.08 Bausch & Lomb INFUSE
Asmofilcon A40161[25] 0.9 0.08 Miru 1month
Verofilcon A51-80
(water gradient)
1000.6 0.09 Alcon Precision1, Alcon Precision1 for Astigmatism
Lehfilcon A55-99
(water gradient)
154[26] 0.6 0.08 Total30
Olifilcon B47
120[27] 0.6 0.08 Kits Daily, Everclear Elite, Hubble SkyHy
Olifilcon A47
150[28] 0.6 0.08 Everclear Plus, Everclear Air

Production generations

There are three generations of silicone hydrogel contact lens materials:[29]

1st Generation 2nd Generation 3rd Generation
Material: Samfilcon A, Comfilcon A, Enfilcon A, Asmofilcon A[30]
Features: TRIS structures, plasma treated, high modulus Modified Tanaka monomer, lack of coatings, higher Dk for water content No TRIS structure, no surface treatments or wetting agents, breaks traditional water-Dk-modulus relationships

Notes and References

  1. Web site: About Contact Lenses - clma.net. clma.net. Contact Lens Manufacturers Association. 18 June 2016.
  2. Web site: Denise Hampton, Ph.D. 13 May 2014. Contact Lens Safety - Ophthalmic Devices Panel. www.fda.gov. FDA Division of Ophthalmic and Ear, Nose and Throat Devices. 97. Microsoft PowerPoint. https://web.archive.org/web/20160618091821/https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/OphthalmicDevicesPanel/UCM397603.pdf. 18 June 2016.
  3. Web site: Caring for Your Vision: Advantages and Disadvantages of Various Types of Contact Lenses. www.aoa.org. American Optometric Association. 18 June 2016.
  4. Web site: Polymers in everyday things – Contact Lenses. rsc.org. Royal Society of Chemistry. 19 June 2016. https://web.archive.org/web/20160619083706/http://www.rsc.org/Education/Teachers/Resources/Inspirational/resources/3.1.1.pdf. 19 June 2016.
  5. Web site: The FDA has created the 4 Lens groups of hydrogels Materials to clarify categories of similar polymers for investigating solutions approvals . 2016-06-28 . 2016-08-10 . https://web.archive.org/web/20160810001411/http://www.aalens.com/fda.html .
  6. Web site: Ophthalmic Devices Panel of the Medical Devices Advisory Committee. FDA Executive Summary Prepared for the May 13, 2014 Meeting of the Ophthalmic Devices Panel of the Medical Devices Advisory Committee. U.S. Food and Drug Administration. 18 June 2016. https://web.archive.org/web/20150807034704/https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/OphthalmicDevicesPanel/UCM395577.pdf. 7 August 2015. 2. English. May 13, 2014.
  7. Loretta B. Szczotka-Flynn . Contact Lens Materials: Advocating a New Lens Group. Contact Lens Spectrum . February 2005 . 18 June 2016. https://web.archive.org/web/20151006080033/http://www.clspectrum.com/articleviewer.aspx?articleID=12748. 6 October 2015. en.
  8. Web site: Contact Lens Compendium. contactlensupdate.com. Contact Lens Spectrum. 18 June 2016.
  9. Web site: Tina Kiang . Joseph Hutter . J Angelo Green . K Scott Phillips . Malvina B Eydelman . Updating the Contact Lens Classification System. Food and Drug Administration . https://web.archive.org/web/20111117204230/https://www.fda.gov/downloads/AboutFDA/CentersOffices/CDRH/CDRHFOIAElectronicReadingRoom/UCM279426.pdf. 17 November 2011 . en. 10 Nov 2011.
  10. Web site: Contact Lenses: Manufacturing/Chemistry. www.fda.gov. U.S. Food and Drug Administration. 18 June 2016. https://web.archive.org/web/20150501105110/https://www.fda.gov/downloads/MedicalDevices/.../ucm080960.pdf. 1 May 2015. 25. n.d..
  11. Web site: Editorial - Should Silicone Hydrogels be Placed in a Separate FDA Soft Contact Lens Category?. www.siliconehydrogels.org. 18 June 2016.
  12. Web site: Stretton . Serina . Should Silicone Hydrogels be Placed in a Separate FDA Soft Contact Lens Category? . siliconehydrogels.org . 3 September 2020 . October 2004.
  13. Web site: Contact Lens Spectrum - Soft Contact Lenses. www.clspectrum.com. Contact Lens Spectrum. 19 Feb 2019.
  14. Web site: CooperVision Product Reference Guide - 2019. coopervision.com. CooperVision. 19 Feb 2019.
  15. Web site: Acuvue Tech Specs - Winter 2017. www.acuvue.com. Johnson & Johnson. 19 Feb 2019.
  16. Web site: Contact Lenses: Bausch + Lomb. www.bausch.com. Bausch & Lomb. 19 Feb 2019.
  17. Web site: Scout by Warby Parker (90 Pack) Contacts. Warby Parker.
  18. Web site: Miru 1 Day Contacts. LensPricer.
  19. Web site: 10.2.4 AONDA Product Page | MyAlcon .
  20. Web site: Dr. Karen French. The Performance of Galyfilcon A. OpticianOnline.Net. Contact Lens Monthly. 18 June 2016. 12 May 2008.
  21. Web site: Dailies TOTAL1® Lens Parameters and Fitting Guide | Alcon .
  22. David L. Kading . May 2014 . New Lens Technology Targets Improved Vision and Comfort . Contact Lens Spectrum . 29.
  23. https://pi.bausch.com/globalassets/pdf/Downloads/ECP/vision-care/lens/Bausch-Lomb-ULTRA-fP-Fitting-Guide-Parameter-Expansion.pdf/?ver=2017-08-17-094359-310 Lens Parameters
  24. Web site: Bausch + Lomb INFUSE - Optix-now. 2020-12-23. Optix-now - Your Vision Care Guide. en-US.
  25. Web site: Miru 1month Menicon America. 2021-05-01. Menicon America. en-US.
  26. Web site: TOTAL30® Parameters and Contact Lens Technology | Alcon .
  27. https://www.accessdata.fda.gov/cdrh_docs/pdf18/K180322.pdf
  28. https://www.accessdata.fda.gov/cdrh_docs/pdf18/K183670.pdf
  29. Web site: Looking at Silicone Hydrogels Across Generations. www.optometricmanagement.com. Optometric Management. 18 June 2016.
  30. Web site: 3rd Generation Silicone Hydrogel Lenses . Carnt . Nicole . www.siliconehydrogels.org . May 2008 . 5 October 2021.