41st Annual Contact Lens Report

Follow the links below to read the other articles from our 41st annual Contact Lens Report:

Sclerals for the Irregular Cornea

Choosing the Right Modality

Corneal Topography for Better Fitting

Even with healthy growth in the number of contact lens (CL) options on the market, one particular burden continues to dog the industry—contact lens discomfort (CLD).1-5 

According to the Tear Film and Ocular Surface Society (TFOS) report on CLD, the only CL material-related factor that demonstrates correlation with CLD is coefficient of friction.6 However, until researchers agree upon an industry-standard methodology to measure friction of CL materials, this remains a difficult area to study. Other material-related factors, such as oxygen transmissibility, wettability, modulus and lens dehydration, only display weak links with CLD. Lens replacement frequency, lens design, thickness/bulk and edge configuration also show some relationship to CLD.5 

Over the past few years, CL companies have debuted technologies aimed at developing lenses with surface and bulk properties that reduce discomfort. Some Silicone hydrogel (SiHy) materials even hope to address patient-related issues, such as digital eyestrain. This article reviews the latest SiHy materials that manufacturers hope will reduce patient discomfort as well as new CL materials and designs of other lens types.

Fig. 1. This patient presented with a mechanical complication known as mucin balls (shown at high magnification on the right). Photos: Jalaiah Varikooty, MSc, BMed
Fig. 1. This patient presented with a mechanical complication known as mucin balls (shown at high magnification on the right). Click image to enlarge. Photos: Jalaiah Varikooty, MSc, BMed

SiHy Setbacks and Successes

This material now accounts for approximately 55% of all soft lens fits worldwide and 62% in the United States.7 Its increased oxygen transmissibility promised a reduction in the rate of corneal infections, but research shows the risk of microbial keratitis is similar regardless of lens material studied.8-12 In fact, several studies show that SiHy materials doubled the relative risk for infiltrative events.13-16 Studies also suggest that older generation SiHy materials provided only a minimal increase in comfort over conventional hydrogel (CH) materials.5,17 This was due to the incorporation of siloxane groups into SiHy lenses, which made them more hydrophobic and stiffer than CH materials, but led to issues related to poor lens wettability and mechanical complications.18-20 These mechanical complications included mucin balls (Figure 1), corneal erosions (Figure 2), superior epithelial arcuate lesions (Figure 3), epithelial flaps and CL-associated papillary conjunctivitis.21-26 The hydrophobic nature of certain SiHy materials tends to deposit high levels of certain lipids and increased denatured protein.27,28 Hence, several practitioners still choose to fit CH materials. 

However, a newer generation of SiHy lenses were designed with these issues in mind. For instance, Air Optix plus with HydraGlyde (Alcon) incorporates two technologies—SmartShield Technology and HydraGlyde Moisture Matrix—which provide a combination of deposit protection and longer-lasting lens surface moisture.29 According to the manufacturer, lenses with “SmartShield technology” prevent silicone from reaching the surface of the CLs, which helps the lens surface retain moisture and resist deposition with the intention of maintaining comfort throughout the wearing period. “HydraGlyde Moisture Matrix” involves a block copolymer. One side of the HydraGlyde molecule adsorbs onto the contact lens; the other attracts additional moisture, which the manufacturer says results in an envelope of lasting lens surface wettability.

In August 2016, CooperVision announced the launch of a new SiHy lens, Avaira Vitality (CooperVision), in sphere and toric options, manufactured from fanfilcon A, which has a high water content (55%) and high oxygen permeability (Dk) and transmissibility level (Dk/t). This material also features a Class I ultraviolent (UV) protection rating, and it blocks more than 90% of long-wave and 99% of shortwave UV rays. In July, CooperVision introduced its Biofinity Energys (CooperVision), with digital device users in mind. According to the company, this comfilcon A-based lens has two novel elements: “digital zone optics,” which integrates multiple, front-surface, aspheric curves across the entire optical zone, distributing power evenly and simulating more positive power in the center of the lens; and “aquaform technology,” which has high oxygen transmissibility and low modulus, attracting and binding water.30

Table 1. Reusable Spherical Silicone Hydrogel Contact Lenses

USANBrand nameReplacement frequency & modality
Proprietary technology Wetting AgentDk/t (-3.00D)
Modulus (Mpa) Water contentBOZR (mm)Diameter (mm)
Alconlotrafilcon A
Air Optix Night & Day Aqua 1 month DW or up to 30N CW Surface treatment: plasma coating
Moisture agent in packaging solution (1% copolymer 845)
175 1.5 24%8.4, 8.813.8
lotrafilcon B
Air Optix Aqua
1 month DW or up to 6N EW
Surface treatment: plasma coating
Moisture agent in packaging solution (1% copolymer 845)
13833% 8.614.2 
lotrafilcon B
Air Optix Aqua plus HydraGlyde
1 month DW or up to 6N EW
Surface treatment: plasma coating
Added HydraGlyde technology 138133%8.6 14.2
Bausch + Lomb balafilcon A
PureVision 1 month DW or up to 30N CW
Surface treatment: plasma oxidation
1011.136%8.3, 8.614.0
balafilcon A
PureVision 2 HD
1 month DW or up to 30N CW
Surface treatment: plasma oxidation
samfilcon A
Ultra1 month DW  MoistureSeal  Internal wetting agent: Polyvinyl pyrrolidone (PVP) 1630.746%8.5 14.2
comfilcon A
1 month DW or up to 7N CW Aquaform technology None160 0.7548%8.614.0
enfilcon A
2 week DW US
Aquaform technology
Integrated Polyethylene Glycol (PEG) 125 0.546%8.4 (+ve); 8.5 (-ve)
fanfilcon A
Avaira Vitality
2 week DW US
Aquaform technology
Johnson & Johnson Vision
senofilcon A
Acuvue Oasys
2 week DW or 6N EW
Hydraclear Plus
Internal wetting agent: PVP
1470.7238%8.4, 8.814.0
galyfilcon A
Acuvue Advance
2 week DW
Internal wetting agent: PVP
860.4347%8.3, 8.714.0
senofilcon C
Acuvue Vita
4 week DW
Internal wetting agent: PVP
147Not available41%8.4, 8.814.0
asmofilcon A
Premio (Miru 1 month)
Premio: 2 week DW or 6N EW; Miru 1 month DW
MeniSilk technology and Nanogloss surface coating
 1610.940%8.3, 8.6 14.0

In 2016, Johnson & Johnson Vision announced a monthly replacement SiHy lens, Acuvue Vita (senofilcon C). This lens material is designed to integrate beneficial lipids found in tears within the lens and also helps to maintain lens hydration with reduced evaporation, all in an effort to improve comfort. Johnson & Johnson Vision also launched Acuvue Oasys 1-Day with “HydraLuxe technology,”which uses a tear-infused design that mimics mucins to help support a stable tear film. The material has an enhanced network of tear-like molecules.

This new lens has an increased diameter to ensure full corneal limbus coverage during blinking and includes enlarged optics to help cover larger pupils in low lighting conditions (Tables 1 and 2). 

In February 2016, Bausch + Lomb announced Ultra for Presbyopia, a monthly replacement SiHy lens that incorporates the company’s “MoistureSeal technology” and three-zone progressive design found in Biotrue OneDay for Presbyopia daily disposable CLs. The company says these lenses “maintain 95% of their moisture for up to 16 hours.”31 Bausch + Lomb’s website say the two-phase manufacturing process of these lenses retains moisture and delivers a highly wettable surface. Phase 1 combines long- and short-chain monomers to formulate a unique silicone backbone. In phase 2, the polyvinylpyrrolidone (PVP) grows around and throughout the silicone backbone. The high volume of PVP at the core is meant to provide moisture retention and the tightly compacted PVP at the surface delivers high wettability. 

Menicon recently launched Rose K2 Soft CL design for the irregular cornea. Rose K lenses are a frequently prescribed lens design for the correction of keratoconus and irregular cornea conditions and are mostly rigid gas permeable lenses. The newly launched Rose K2 Soft design is a daily wear SiHy soft lens for irregular corneas, available as a three-month replacement lens. The Rose K2 Soft design features an aspheric back optic zone, front surface toricity and front surface aberration control. According to the company, Rose K2 Soft offers edge lift control, prism ballast stabilization and reverse geometry.32 Rose K2 Soft is available now in the United States from ABB Optical, Art Optical Contact Lens and Blanchard Contact Lens.

Table 2. Daily Disposable Spherical Silicone Hydrogel Contact Lenses

ManufacturerUSANBrand nameProprietary technology
Wetting agentDk/t (-3.00D)
Modulus (Mpa)
Water contentBOZR (mm)Diameter (mm)
Alcondelefilcon A

Dailies Total 1
Water gradient technology
None1560.6333% core t>80% surface
CooperVisionstenfilcon A
MyDay Smart Silicone
None1000.454%8.4 14.2
somofilcon A
Clariti 1 Day
WetLoc technologyNone860.556%8.614.1
Johnson & Johnson Vision
narafilcon A
1 Day Acuvue TruEye
Hydraclear 1Internal wetting agent: PVP
1180.6646%8.5, 9.0
senofilcon A
Acuvue Oasys daily contact lens with Hydraluxe
Internal wetting agent: PVP
1210.7238%8.5, 9.0

Scleral Lenses 

Over the last decade, CL manufacturers have provided a variety of scleral contact lens (ScCL) designs that have a wide range of applications.33,34 Current ScCLs are manufactured using high Dk materials (e.g., fluorosilicone acrylate). Such materials aid in increasing oxygen supply to the cornea. 

Asian patients’ corneas have a smaller horizontal visible iris diameter and are more prolate with a smaller palpebral fissure than Caucasians’ corneas.35 Blanchard designed a lens (Onefit A Scleral lens) to provide optimal limbal clearance and easier handling with a smaller diameter and an altered paracentral geometry.36 Blanchard also launched a new feature called XLC (Extra Limbal Clearance), to its Onefit Scleral Lens Platform to obtain additional limbal clearance, without increasing the lens diameter. In March 2016, Art Optical announced the availability of its new 16.5mm scleral lens, Ampleye. According to the company, this is designed to fully vault the cornea and limbus, without corneal involvement.37 In addition to a toric haptic, the lenses include a four-zone construction, providing independent zone adjustments for finite control of the lens fit. 

The SynergEyes VS (Menicon) scleral lens completely vaults the cornea and limbus, landing entirely on the sclera.38 Its toric periphery may be precisely controlled in both the flat and steep meridians, aligning with the scleral for ease of landing and stability.38 This non-rotationally symmetrical lens design incorporates linear landing zones and landing zones with bi-tangential toricity.38 The linear landing zones are designed to follow the linear (rather than curved) shape of the sclera, accommodating a toric sclera.38 This should distribute the lens pressure more equally over the sclera due to the adjustable angles of the flat or steep meridians.38 The company hopes this will improve the scleral lens fit with less risk of air bubble formation or blanching of the conjunctival scleral vessels.38 The toric landing zones can greatly improve vision in patients with residual astigmatism as they are designed to provide consistent
stabilization allowing for a front-surface cylinder. 

Table 3. SiHy and Conventional Toric Hydrogel Contact Lenses

CompanyUSANBrand nameReplacement frequencyWater contentDiameter (mm)BOZR (mm)Lens typeDesign/Stabilization method/markings
Alconlotrafilcon B
Air Optix for Astigmatism
1 month DW or up to 6N EW
33%14.58.7SiHyPrecision balance 8/4 lens design. Markings at 3, 6 and 9 o’clock
nelfilcon A
Focus Dailies Toric One-Day
Daily69%14.28.6hydrogelBack surface tri-curve toric design
nelfilcon A
Dailies Aquacomfort Plus Toric (nelfilcon A) One-Day
Daily69%14.48.8hydrogelBack surface tri-curve toric design
Bausch + Lomb
balafilcon A
PureVision Toric
1 month DW or up to 30N CW
36%14 8.7 SiHyPrism ballast Lo-Torque Design; Marking at 5, 6 and 7 o’clock; (30 degrees apart)
balafilcon A
PureVision2 Toric for Astigmatism
1 month DW or up to 30N CW
36%14.58.9SiHyAspheric optics; Auto Align Design; Marking at 6 o’clock
alphafilcon A
Soflens Toric for Astigmatism
1 month66%14.58.5hydrogelPrism ballast; Marking at 5, 6 and 7 o’clock (30 degrees apart)
nesofilcon A
Biotrue OneDay for Astigmatism
Daily78%14.58.4hydrogelPeri-ballast (prism free) 
hilafilcon B
SofLens daily disposables Toric for Astigmatism
Daily 59%14.28.6hydrogelPrism ballast; Aspheric design
comfilcon A
Biofinity Toric
1 month DW or up to 7N CW
48%14.58.7SiHyOptimized ballast design; Marking at 6 o’clock 
enfilcon A
Avaira Toric
Two-week46%14.58.5SiHyOptimized ballast design; Marking at 6 o’clock
fanfilcon A
Avaira Vitality toric
 Two-week55%14.58.5SiHyOptimized Toric Lens Geometry
omafilcon A
Proclear Toric
1 month62%14.48.4, 8.8hydrogelPrism ballast; Three lines at 6 o’clock (15 degrees apart)
ocufilcon D
Biomedics Toric
1 month55%14.58.7hydrogelPrism Ballast; Marking at 6 o’clock
methafilcon A
Frequency 55 Toric/Xcel Toric
1 month55%14.48.7hydrogelPrism ballast
somofilcon A
clariti 1 day toric
Daily56%14.38.6 SiHyAspheric
Johnson & Johnson Vision
senofilcon A
Acuvue Oasys for astigmatism
2 week DW38%14.58.6SiHyAccelerated Stabilization Design
etafilcon A
1-Day Acuvue Moist for Astigmatism
Daily58%14.58.5hydrogelAccelerated Stabilization Design
senofilcon A Acuvue Oasys for Astigmatism with HydraLuxe Daily 38%14.38.5SiHyAccelerated Stabilization Design

Myopia Control Lenses

Recent research shows a 32% to 42% reduction in myopia using orthokeratology (OK) lenses.39-41 Research also finds partial correction using OK lenses is effective, with high myopes of 6.00D or more partially treated by -4.00D, showing a 76% reduction in myopia progression over one year when compared with spectacle wear.42 Children fitted with a dual-focus multifocal OK lens design in one eye and a conventional OK lens in the fellow eye showed short-term changes to the eye in the multifocal OK lens wearing eyes.43 

Concentric and aspheric multifocal designs can slow myopia progression.44 Concentric bifocal lenses, which have a center distance design surrounded by concentric zones of near and distance powers, reduce myopia progression and axial length in children with esophoric fixation disparities, according to investigators.44 Aspheric designs also show reduced myopia progression.45 Use of a center-distance aspheric multifocal design can reduce myopic progression by 50% and axial length by 29% when compared with a single vision wearing group.46

Dual-focus designs and peripheral plus powered aspheric designs also show myopia reduction; however, debate about the visual quality reduction caused by the induction of positive spherical aberration when using this approach persists.47-50 

Fig. 2. This patient displayed epithelial erosion one hour after removing their contact lenses. Photo: Jalaiah Varikooty, MSc, BMed

Toric Lenses for Astigmatism

A number of new options have recently come to market in this category. In 2017, Bausch + Lomb introduced Biotrue OneDay for Astigmatism daily disposable CLs (nesofilcon A). Initially, these lenses will be available in plano to -4.25D (in 0.25D steps) with cylinder powers of -0.75D and -1.25D and the full range will be available later this year. Johnson & Johnson Vision announced the US launch of Acuvue Oasys 1-Day Brand CLs for Astigmatism. CooperVision announced the limited rollout of Avaira Vitality toric (in the fanfilcon A material). This lens has an optimized ballast toric design and is available in a power range of plano to -6.00D with cylinder options of 0.75D, 1.25D, and 1.75D in axes from 10° to 180° in 10° steps. They have a modulus of 0.6MPa and a Dk/t of 90. Announcements about plus powers, high minus powers and a -2.25 cylinder are expected later in 2017. In June 2016, CooperVision announced the expanded availability of Biofinity XR toric, a monthly SiHy CL. Biofinity XR toric is a cast-molded, made-to-order lens that incorporates the same uniform horizontal thickness and ballast band design as Biofinity toric. The commercially available SiHy and CH toric hydrogel CLs, and the stabilization methods and markings used in their lenses, is available for review (Table 3). 

Table 4. SiHy and Conventional Multifocal Hydrogel Contact Lenses

CompanyUSANBrand nameReplacement frequencyWater content (%)Diameter (mm)BOZR (mm)Lens type
Alcon lotrafilcon B
Air Optix Aqua Multifocal
monthly 3314.28.6SiHy
nelfilcon A
Focus Dailies Progressives
nelfilcon A
Dailies AquaComfort Plus Multifocal
daily69148.7 hydrogel
delefilcon A
Dailies Total1 Multifocal
Bausch + Lomb balafilcon A
PureVision Multi-Focal
balafilcon A
PureVision2 for Presbyopia
nesofilcon A
Biotrue OneDay for Presbyopia
daily7814.2 8.6hydrogel
samfilcon A
Ultra for Presbyopia
polymacon B
SofLens Multi-Focal
monthly3814.58.5, 8.8hydrogel
CooperVision somofilcon A
clariti 1 day multifocal
comfilcon A
Biofinity multifocal
omafilcon A
Proclear Multifocal
omafilcon A
Proclear 1 day multifocal
Johnson & Johnson Vision
senofilcon A
Acuvue Oasys For Presbyopia
bi-weekly*38 14.38.4SiHy
etafilcon A
1-Day Acuvue Moist Multifocal
*If used in an EW modality, weekly replacement.

Presbyopia Correction

Multifocal lenses have shown improved success in correcting presbyopia when compared with monovision.51-53 Commercially available options are shown in  (Table 4).

Last year, PolyVue launched HD Dailies (hioxifilcon, 59% water content), which incorporate an aspheric curvature for each soft lens power and thickness, and compensate for aberrations caused by lens flexure on the eye. Alcon also introduced Dailies Total1 Multifocal CLs (delefilcon A), which uses the same water-gradient technology as the other lenses in the DT1 product line. 

The water gradient technology incorporates what the manufacturer calls core and surface optimization: the core material has 33% water content (low water content helps to deliver high oxygen transmissibility) and the surface employs a hydrophilic gel designed to provide lubricity (>80% water). The outer surface has no silicone and is 100% water.

Fig. 3. Superior epithelial arcuate lesions, as seen here, can result mechanical friction of the lens on the cornea. Mostly seen in those who wear high-modulus silicone hydrogel contact lenses.
Fig. 3. Superior epithelial arcuate lesions, as seen here, can result mechanical friction of the lens on the cornea. Mostly seen in those who wear high-modulus silicone hydrogel contact lenses. Click image to enlarge.

Cosmetic Lenses

Color CL fits in Asia are quite high when compared with the United States, with about 4% in the United States, and 58% and 41% in Taiwan and Korea.7 Color CLs are mainly used for cosmetic purposes and they also have prosthetic and special effect applications. There are three types of color soft CL that are used to enhance or alter the eye color: transparent tinted lenses, dot matrix computer-generated lenses, and custom hand-painted soft lenses. Lately, the market has seen a huge increase in the sales of limbal ring CLs. Limbal ring CLs magnify the eye appearance and this is achieved by adding pigments to these lenses. These pigments can be located either on the surface or within the bulk of the limbal CL material. Pigment location on seven different daily disposable limbal ring CL materials was studied and, aside from one lens material, all tested lens materials revealed pigments on the surface.54 The pigments located on the surface of the CL will either interact with the palpebral conjunctiva or the cornea depending on location of the surface coating (front or back). 

Discomfort associated with CL wear continues to be an issue cannot be attributed to any single factor. Further studies are warranted to understand the impact of these new technologies on CL comfort. Novel CL materials and designs have evolved over the past decade. It would be useful for optometrists to stay up to date on novel innovations in CL materials and designs when prescribing, to avoid or solve a number of common patient problems. 

Dr. Srinivasan is an optometrist at the Centre for Contact Lens Research (CCLR), School of Optometry and Vision Science, at the University of Waterloo, Ontario, Canada. 

1. Nichols J. Contact lenses 2016 a status quo remains for much of the contact lens industry. Contact Lens Spectrum. 2017;32:22-55.
2. Nichols J, Willcox M, Bron A, et al. The TFOS international workshop on contact lens discomfort: executive summary. Invest Ophthalmol Vis Sci. 2013;54:TFOS7-TFOS13.
3. 2015 Digital Eye Strain Report. The Vision Council. www.thevisioncouncil.org/content/digital-eye-strain. January 7, 2015. Accessed July 20, 2017.
4. Dumbleton K, Caffery B, Dogru M, et al. The TFOS International Workshop on Contact Lens Discomfort: report of the subcommittee on epidemiology. Invest Ophthalmol Vis Sci. 2013;54:TFOS20-36.
5. Jones L, Brennan NA, Gonzalez-Meijome J, et al. The TFOS International Workshop on Contact Lens Discomfort: report of the contact lens materials, design, and care subcommittee. Invest Ophthalmol Vis Sci. 2013;54:TFOS37-70.
6. Coles C, Brennan N. Coefficient of friction and soft contact lens comfort. American Academy of Optometry. www.aaopt.org/coefficient-friction-and-soft-contact-lens-comfort. 2012. Accessed July 20, 2017. 
7. Morgan P, Woods C, Tranoudis I, et al. International contact lens prescribing in 2016. Contact Lens Spectrum. 2017;32(1):30-5.
8. Sweeney D, du Toit R, Keay L, et al. Clinical performance of silicone hydrogel lenses in Silicone hydrogels: continuous wear contact lenses. Oxford:Butterworth-Heinemann;2004:164-216. 
9. Holden B, Sweeney D, Sankaridurg P, et al. Microbial keratitis and vision loss with contact lenses. Eye Contact Lens. 2003;29:S131-4.
10. Schein O, McNally J, Katz J, et al. The incidence of microbial keratitis among wearers of a 30-day silicone hydrogel extended-wear contact lens. Ophthalmology. 2005;112(12):2172-9.
11. Stapleton F, Keay L, Edwards K, Holden B. The epidemiology of microbial keratitis with silicone hydrogel contact lenses. Eye Contact Lens. 2013;39(1):79-85.
12. Stapleton F, Keay L, Edwards K, et al. The incidence of contact lens-related microbial keratitis in Australia. Ophthalmology. 2008;115(10):1655-62.
13. Chalmers R, Wagner H, Mitchell G. Age and other risk factors for corneal infiltrative and inflammatory events in young soft contact lens wearers from the contact lens assessment in youth (CLAY) study. Invest Ophthalmol Vis Sci. 2011;52(9):6690-6.
14. Chalmers R, Keay L, McNally J, Kern J. Multicenter case-control study of the role of lens materials and care products on the development of corneal infiltrates. Optom Vis Sci. 2012;89(3):316-25.
15. Chalmers R, Keay L, Long B, et al. Risk factors for contact lens complications in US clinical practices. Optom Vis Sci. 2010;87(10):725-35.
16. Szczotka-Flynn L, Diaz M. Risk of corneal inflammatory events with silicone hydrogel and low Dk hydrogel extended contact lens wear: a meta-analysis. Optom Vis Sci. 2007;84(4):247-56.
17. Guillon M. Are silicone hydrogel contact lenses more comfortable than hydrogel contact lenses? Eye Contact Lens. 2013;39(1):86-92.
18. Sweeney D. Silicone hydrogels: the rebirth of continuous wear contact lenses. Oxford: Butterworth-Heinemann;2000.
19. Jones L, Subbaraman L, Rogers R, Dumbleton K. Surface treatment, wetting and modulus of silicone hydrogels. Optician. 2006;232:28-34.
20. Dumbleton K. Adverse events with silicone hydrogel continuous wear. Cont Lens Anterior Eye 2002;25(3):137-46.
21. Holden B, Stephenson A, Stretton S, et al. Superior epithelial arcuate lesions with soft contact lens wear. Optom Vis Sci. 2001;78(1):9-12.
22. Dumbleton K, Jones L, Chalmers R. Clinical characterization of spherical post-lens debris associated with lotrafilcon high-Dk silicone lenses. CLAO J. 2000;26(4):186-92.
23. Bergmanson J, Tukler J, Leach N, et al. Morphology of contact lens-induced conjunctival epithelial flaps: a pilot study. Cont Lens Anterior Eye. 2012;35(4):185-8.
24. Skotnitsky C, Sankaridurg P, Sweeney D. General and local contact lens induced papillary conjunctivitis (CLPC). Clin Exp Optom. 2002;85(3):193-97.
25. Skotnitsky C, Naduvilath T, Sweeney D. Two presentations of contact lens-induced papillary conjunctivitis (CLPC) in hydrogel lens wear: Local and general. Optom Vis Sci. 2006;83(1):27-36.
26. Dumbleton K. Noninflammatory silicone hydrogel contact lens complications. Eye Contact Lens. 2003;29(1):S186-9.
27. Omali N, Subbaraman L, Coles-Brennan C, et al. Biological and clinical implications of lysozyme deposition on soft contact lenses. Optom Vis Sci. 2015;92(7):750-7.
28. Lorentz H, Jones L. Lipid deposition on hydrogel contact lenses: how history can help us today. Optom Vis Sci. 2007;84(4):286-95.
29. Nash W, Gabriel M. Ex vivo analysis of cholesterol deposition for commercially available silicone hydrogel contact lenses using a fluorometric enzymatic assay. Eye Contact Lens. 2014;40(5):277-82.
30.  CooperVision Insight Newsletter. Coopervision unveils biofinity energys contact lenses. Coopervision. coopervision.com/practitioner/build-your-practice/insight-newsletter/coopervision-unveils-biofinity-energys™-contact-lenses. July/August 2017. Accessed July 20, 2017.
31. MoistureSeal technology. Bausch + Lomb. www.bausch.com/our-products/contact-lenses/lenses-for-nearsighted-farsighted/bausch-lomb-ultra-contact-lenses/moistureseal-technology. Accessed July 20, 2017.
32. Rose K2 Soft. Practitioner’s Fitting Guide. Artoptical. www.artoptical.com/storage/docs/RKS_FG.pdf. 2016. Accessed July 20, 2017.
33. Pullum K, Whiting M, Buckley R. Scleral contact lenses: the expanding role. Cornea. 2005;24(3):269-77.
34. Pecego M, Barnett M, Mannis M, Durbin-Johnson B. Jupiter scleral lenses: the UC Davis Eye Center experience. Eye Contact Lens. 2012;38(3):179-82.
35. Hickson-Curran S, Brennan N, Igarashi Y, Young G. Comparative evaluation of Asian and white ocular topography. Optom Vis Sci. 2014 Dec;91(12):1396-405.
36. Blanchard Contact Lenses. Blanchard launches new scleral lens design for Asian eye—Onefit A now available. Blanchard Lab. blanchardlab.com/blanchard-u/news/6566/. May 19, 2016. Accessed July 20, 2017.
37. Ampleye Scleral GP. Professional fitting instructions. www.artoptical.com/storage/docs/Ampleye_Fitting_Booklet.pdf. 2016. Accessed July 20, 2017.
38. Scleral Lenses: SynergEyes VS. Synergeyes. https://synergeyes.com/professional/specialty-contact-lenses-scleral-vs/. 2017. Accessed July 20, 2017.
39. Chan KY, Cheung SW, Cho P. Orthokeratology for slowing myopic progression in a pair of identical twins. Cont Lens Anterior Eye. 2014;37(2):116-9.
40. Santodomingo-Rubido J, Villa-Collar C, Gilmartin B, Gutierrez-Ortega R. Myopia control with orthokeratology contact lenses in Spain: refractive and biometric changes. Invest Ophthalmol Vis Sci. 2012;53(8):5060-5.
41. Hiraoka T, Kakita T, Okamoto F, et al. Long-term effect of overnight orthokeratology on axial length elongation in childhood myopia: a 5-year follow-up study. Invest Ophthalmol Vis Sci. 2012;53(7):3913-9.
42. Charm J, Cho P: High myopia-partial reduction orthokeratology (HM-PRO): study design. Cont Lens Anterior Eye 2013;36:164-70.
43. Loertscher M: Multifocal orthokeratology associated with rapid shortening of vitreous chamber depth in eyes of myopic children. Contact Lens Ant Eye. 2013;36(Suppl.):e2.
44. Aller T, Laure A, Wildsoet C. Results of a one-year prospective clinical trial (CONTROL) of the use of bifocal soft contact lenses to control myopia progression. Ophthalmic Physiol Opt. 2006;26(Suppl.):8-9.
45. Atchison D. Optical models for human myopic eyes. Vision Res. 2006;46:2236-50.
46. Walline J, Greiner K, McVey M, Jones-Jordan L. Multifocal contact lens myopia control. Optom Vis Sci 2013;90:1207-14.
47. Anstice N, Phillips J. Effect of dual-focus soft contact lens wear on axial myopia progression in children. Ophthalmology. 2011;118:1152-61.
48. Sankaridurg P, Holden B, Smith E. Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results. Invest Ophthalmol Vis Sci. 2011;52:9362-7.
49. Kollbaum P, Jansen M, Tan J. Vision performance with a contact lens designed to slow myopia progression. Optom Vis Sci. 2013;90:205-14.
50. Cheng X, Chehab K, Brennan N. Controlling myopia progression with positive spherical aberration in soft contact lenses. Optom Vis Sci. 2013;90:E-abstract 130252.
51. Woods J, Woods C, Fonn D. Early symptomatic presbyopes—what correction modality works best? Eye Contact Lens. 2009;35:221-6.
52. Richdale K, Mitchell GL, Zadnik K. Comparison of multifocal and monovision soft contact lens corrections in patients with low-astigmatic presbyopia. Optom Vis Sci. 2006;83:266-73.
53. Ferrer-Blasco T, Madrid-Costa D: Stereoacuity with balanced presbyopic contact lenses. Clin Exp Optom. 2011;94:76-81.
54. Osborn-Lorenz K, Kakkassery J, Boree D, Pinto D. Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses. Clin Exp Optom. 2014;97:411-417.