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

Background

It has been suggested that this section be split out and merged into the article titled Contact lens#Soft lenses, which already exists. (Discuss) (January 2022)

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:

made of soft, flexible plastics that allow oxygen to pass through to the cornea. Soft contact lenses may be easier to adjust to and are more comfortable than rigid gas permeable lenses. Newer soft lens materials include silicone-hydrogels to provide more oxygen to your eye while you wear your lenses.[4]

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.[5] 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.[5]

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.[6] 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".[7]

The FDA has been considering updating soft contact lens group types and related guidance literature.[8][9][10]

Contact lens polymers

The materials that are classified in the 5 FDA groups include the ones listed in the next 5 sections:[11][12]

FDA classification of soft contact lens materials[13]
FDA lens group Adopted name Transmissibility level

(Dk x10-11)

Water content Chemical composition
I
non-ionic
low water content 		galyfilcon A 60 47% –
lotrafilcon A 140 24% DMA, siloxane, TRIS
lotrafilcon B 110 33%
polymacon 7.5 36% HEMA
tetrafilcon 9.0 43.5% HEMA, MMA, NVP
II
non-ionic
high water content 		alphafilcon A 22.9 66% HEMA, NVP
hilafilcon A 26.9 70%
omafilcon A 19.6 62% HEMA, PC
III
ionic
low water content 		balafilcon A 99 36% NCVE, NVP, PBVC, TPVC
bufilcon A 16.0 45% DA, HEMA, MAA
IV
ionic
high water content 		etafilcon A 17.0 58% HEMA, MAA
ocufilcon D 19.7 55%
vifilcon A 16.0 55% HEMA, MAA, PVP
DA – diacetone acrylamide; DMA – N,N-dimethylacrylamide; HEMA – 2-Hydroxyethyl methacrylate; MAA – methacrylic acid; MMA – methyl methacrylate; NCVE – N-carboxl vinyl ester; NVP – N-vinyl pyrrolidone; PBVC – poly[dimethylsiloxyl] di[silybutanol] bis[vinyl carbamate]; PC – phosphorylcholine; TPVC – tris-(trimethylsiloxysilyl) propylvinyl carbamate; TRIS – tris-(hydroxylmethyl) aminomethane


Hydrogel groups

Below is a list of most contact lens materials on the market, their water percentage, their oxygen permeability rating, and manufacturer brands.[14][15][16][17] 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
Tetrafilcon A 43 9 Cooper Clear, Cooper Toric, Preference, Preference Toric, Vantage, Vantage Accents, Vantage Thin, Vantage Thin Accents
Crofilcon 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
Polymacon 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
Hioxifilcon B 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
Surfilcon A 74 35
Lidofilcon A 70 31 ActiFresh 400, CV 70
Lidofilcon B 79 38
Netrafilcon A 65 34.5
Hefilcon B 45 10 Optima Toric
Alphafilcon A 66 32 SofLens Toric for Astigmatism
Omafilcon A 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
Vasurfilcon A 74 39.1 Precision UV
Hioxifilcon A 59 28 Alden HP Sphere, Alden HP Toric, ExtremeH₂O 59% Thin/Extra, Biocurve Gold Sphere and Toric, Aura ADM, Scout by Warby Parker,[18] Hydro by Hubble, Miru 1 Day[19]
Hioxifilcon D 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
Hilafilcon A 70 35
Hilafilcon B 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
Bufilcon A 45 16 Hydrocurve II 45, Soft Mate B
Deltafilcon A 43 10 Amsoft, Amsoft Thin, Comfort Flex, Custom Flex, Metrosoft, Soft Form Toric
Phemfilcon 38 9 Durasoft 2

High Water ionic

Material % Water Oxygen Transmissibility (Dk/t) Brands
Bufilcon A 55 16 Hydrocurve I, Hydrocurve 3 Toric, Softmate II
Perfilcon A 71 34 Permalens
Etafilcon A 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
Focofilcon A 55 16 Fre-Flex
Ocufilcon B 52-53 16-24 ClearSight 1-Day, Continental, Ocu-Flex 53
Ocufilcon C 55 16 UCL55, UCL-Pediatric
Ocufilcon D 55 17.8-28.1 Biomedics 55 Premier asphere, Biomedics Toric, ClearSight 1-Day Toric, Horien 1-Day Disposable
Ocufilcon E 65 22 Ocuflex 65
Ocufilcon F 60 24.3 Hydrogenics 60 UV
Phemfilcon A 55 16 Durasoft 3, Freshlook, Wildeyes
Methafilcon A 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
Methafilcon B 55 14.5-31.3 Frequency 55 Toric, Hydrasoft Sphere, Hydrasoft Sphere Thin, Hydrasoft Aphakic, Hydrasoft Aphakic Thin, Hydrasoft Toric, Hydrasoft Toric Thin
Vilfilcon A 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
Lotrafilcon A 1 24 175[20] 1.5 0.08 Air Optix Night & Day Aqua
Lotrafilcon B 1 33 110-138 1.0 0.08 O2Optix, Air Optix for Astigmatism, Air Optix Aqua, Air Optix Aqua Multifocal
Galyfilcon A 1 47 86[21] 0.43 0.07 Acuvue Advance with Hydraclear, Acuvue Advance for Astigmatism
Senofilcon A 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
Comfilcon A 1 48 116-160 0.75 0.08 Biofinity, Biofinity toric, Biofinity XR, Biofinity XR toric, Biofinity Energys, Biofinity multifocal
Enfilcon A 1 46 100 0.6 0.06 Avaira, Avaira Toric
Balafilcon A 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[22] 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
Somofilcon A 56 57-86 0.5 0.07 Clariti 1 day, Clariti 1 day toric, Clariti 1 day multifocal
Fanfilcon A 55 90-110 0.6 0.06 Avaira Vitality, Avaira Vitality toric, 24H Toric
Samfilcon A 46[23] 163[24] 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 A 55 134[25] 0.5 0.08 Bausch & Lomb INFUSE
Asmofilcon A 40 161[26] 0.9 0.08 Miru 1month
Verofilcon A 51-80
(water gradient) 		100 0.6 0.09 Alcon Precision1, Alcon Precision1 for Astigmatism
Lehfilcon A 55-99
(water gradient) 		154[27] 0.6 0.08 Total30

Production generations

There are three generations of silicone hydrogel contact lens materials:[28]

1st Generation 2nd Generation 3rd Generation
Material: Lotrafilcon A, Balafilcon A Senofilcon A, Galyfilcon A Samfilcon A, Comfilcon A, Enfilcon A, Asmofilcon A[29]
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

References

  1. ^ "About Contact Lenses - clma.net". clma.net. Contact Lens Manufacturers Association. Retrieved 18 June 2016.
  2. ^ Denise Hampton, Ph.D (13 May 2014). "Contact Lens Safety - Ophthalmic Devices Panel" (PDF). www.fda.gov. FDA Division of Ophthalmic and Ear, Nose and Throat Devices. p. 97. Archived from the original (Microsoft PowerPoint) on 18 June 2016.
  3. ^ "Caring for Your Vision: Advantages and Disadvantages of Various Types of Contact Lenses". www.aoa.org. American Optometric Association. Retrieved 18 June 2016.
  4. ^ Center for Devices and Radiological Health. "Contact Lenses - Types of Contact Lenses". www.fda.gov. U.S. Food and Drug Administration. Retrieved 18 June 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ a b "Polymers in everyday things – Contact Lenses" (PDF). rsc.org. Royal Society of Chemistry. Archived from the original (PDF) on 19 June 2016. Retrieved 19 June 2016.
  6. ^ "The FDA has created the 4 Lens groups of hydrogels Materials to clarify categories of similar polymers for investigating solutions approvals". Archived from the original on 2016-08-10. Retrieved 2016-06-28.
  7. ^ Ophthalmic Devices Panel of the Medical Devices Advisory Committee (May 13, 2014). "FDA Executive Summary Prepared for the May 13, 2014 Meeting of the Ophthalmic Devices Panel of the Medical Devices Advisory Committee" (PDF). U.S. Food and Drug Administration. p. 2. Archived from the original (PDF) on 7 August 2015. Retrieved 18 June 2016.
  8. ^ Loretta B. Szczotka-Flynn (February 2005). "Contact Lens Materials: Advocating a New Lens Group". Contact Lens Spectrum. Archived from the original on 6 October 2015. Retrieved 18 June 2016.
  9. ^ "Contact Lens Compendium". contactlensupdate.com. Contact Lens Spectrum. Retrieved 18 June 2016.
  10. ^ Tina Kiang; Joseph Hutter; J Angelo Green; K Scott Phillips; Malvina B Eydelman (10 Nov 2011). "Updating the Contact Lens Classification System" (PDF). Food and Drug Administration. Archived from the original (PDF) on 17 November 2011.
  11. ^ "Contact Lenses: Manufacturing/Chemistry" (PDF). www.fda.gov. U.S. Food and Drug Administration. n.d. p. 25. Archived from the original (PDF) on 1 May 2015. Retrieved 18 June 2016.
  12. ^ "Editorial - Should Silicone Hydrogels be Placed in a Separate FDA Soft Contact Lens Category?". www.siliconehydrogels.org. Retrieved 18 June 2016.
  13. ^ Stretton, Serina (October 2004). "Should Silicone Hydrogels be Placed in a Separate FDA Soft Contact Lens Category?". siliconehydrogels.org. Retrieved 3 September 2020.
  14. ^ "Contact Lens Spectrum - Soft Contact Lenses". www.clspectrum.com. Contact Lens Spectrum. Retrieved 19 Feb 2019.
  15. ^ "CooperVision Product Reference Guide - 2019" (PDF). coopervision.com. CooperVision. Retrieved 19 Feb 2019.
  16. ^ "Acuvue Tech Specs - Winter 2017" (PDF). www.acuvue.com. Johnson & Johnson. Retrieved 19 Feb 2019.
  17. ^ "Contact Lenses: Bausch + Lomb". www.bausch.com. Bausch & Lomb. Retrieved 19 Feb 2019.
  18. ^ "Scout by Warby Parker (90 Pack) Contacts". Warby Parker.
  19. ^ "Miru 1 Day Contacts". LensPricer.
  20. ^ "10.2.4 AONDA Product Page | MyAlcon".
  21. ^ Dr. Karen French (12 May 2008). "The Performance of Galyfilcon A" (PDF). OpticianOnline.Net. Contact Lens Monthly. Retrieved 18 June 2016.
  22. ^ "Dailies TOTAL1® Lens Parameters and Fitting Guide | Alcon".
  23. ^ David L. Kading (May 2014). "New Lens Technology Targets Improved Vision and Comfort". Contact Lens Spectrum. Vol. 29.
  24. ^ Lens Parameters pi.bausch.com Retrieved 30 March 2023
  25. ^ "Bausch + Lomb INFUSE - Optix-now". Optix-now - Your Vision Care Guide. Retrieved 2020-12-23.
  26. ^ "Miru 1month | Menicon America". Menicon America. Retrieved 2021-05-01.
  27. ^ "TOTAL30® Parameters and Contact Lens Technology | Alcon".
  28. ^ "Looking at Silicone Hydrogels Across Generations". www.optometricmanagement.com. Optometric Management. Retrieved 18 June 2016.
  29. ^ Carnt, Nicole (May 2008). "3rd Generation Silicone Hydrogel Lenses". www.siliconehydrogels.org. Retrieved 5 October 2021.
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