A Guide to Contact Lens Technologies

Roshni Patel

Professional Services Manager at Lenstore

About Author

Over the last four decades, the contact lens industry has evolved, seeing contact lenses now regularly being used as an alternative to glasses for the correction of myopia, hyperopia, presbyopia and astigmatism, as well as for surgical purposes and keratoconus. A recent study shows that 93% of adult contact lens wearers in the US wear soft contact lenses and the remaining 7% wearing RGPs. Modern lifestyle changes have further caused an increasing demand for daily disposable silicone hydrogel lenses. 

With such a variety of soft contact lenses on the market, the easy option is to fit a lens type based on parameters, wearing times and optometrists’ personal preferences of manufacturers and brands. However, by familiarising ourselves, not just with materials, but also the water content and modulus, we can reduce the risk of ocular irritation and frequent discomfort, leading to contact lens dropout. The following guide will outline popular manufacturers of soft contact lenses and the technologies and attributes implemented in their product lines

Leading manufacturers and brands

A report from 2019 shows an increased demand for contact lenses over the last decade, which can be expected to continuously rise over to the next. The key global manufacturers of soft contacts include Bausch & Lomb, CooperVision, Johnson & Johnson and Novartis with the subdivision Alcon. Additionally, Menicon produces soft and GP lenses and Conforma focuses on specialized contacts. The following will explore the soft contact lens types that the key manufacturers focus on, the variety of their brands, special attributes, and technologies.

Bausch & Lomb

MoistureSeal

This technology is used in the manufacturing process of the ULTRA range. It refers to the silicone hydrogel material, manufactured with two distinct phases of polymerization. The first phase adds a high Dk/t of 163 and a low modulus, due to three proprietary silicone chains in a matrix. The second phase is time-delayed and the hydrophilic PVP is grown in and around the matrix. The manufacturing process creates a high volume of PVP, permanently installed to allow a higher water content within the lens. The low modulus created by means of the water content reduces the impact on the ocular surface during wear and offers a higher level of comfort.

Comfort Moist

This technology is applied to the Soflens Daily Disposable and the PureVision 2 HD range. It allows for a thin lens design of 0.09mm in the center and 0.07mm towards the lens edge, to reduce corneal irritation and give the lens a more natural feel on the eye, throughout the day.

HygerGel

Applied to the Biotrue range, this technology mimics the water content of the cornea with 78%. The surface-active agent in the liquid polymer shifts to the surface during manufacturing, to ensure that the outer surface layer locks in moisture and prevents dehydration, similar to the lipid layer of the tears. As a hydrogel lens with a high Dk/t of 42, it allows a sufficient amount of oxygen to the cornea.

CooperVision

Aquaform Technology

This combination of technologies and materials is applied to the Biofinity, Avaira Vitality and MyDay range to bind water within the lens material, without the need of additives or coatings. It is manufactured with hydrogen bonds in a matrix that uses a macromer of long silicone chains to optimize the oxygen transmissibility. This reduces the number of molecular bridges and builds an ideal modulus. This technology also includes a rounded edge design that prevents ocular irritation.

Smart Silicone Chemistry

Applied to the MyDay range, to shape silicone in a structure that allows efficient oxygen permeability. This technology requires less raw silicone molecules and can therefore combine them with more hydrophilic material to allow micro-channels smaller than the wavelength of light. This creates a low modulus and flexibility similar to a hydrogel lens, for easier handling and a comfortable fit on the ocular tissue.

WetLoc Technology

This technology is applied to the Clariti 1 Day range and ensures that moisture spreads throughout the lens. It relies on a hydrophilic silicone-structure, rather than surface treatments, and binds water molecules to the lens. This creates a higher water content and allows the lens to imitate the moisture distribution of eyes.

Johnson & Johnson

Lacreon

Applied to the 1 Day Acuvue Moist range, PVP is added as a wetting agent after the lens is polymerised to include a hydrophilic polymer of high molecular weight and bind water molecules to the matrix of the lens. As this wetting agent is embedded within the lenses, it doesn't evaporate during the day.

Hydraclear Plus

This technology is applied to the Acuvue Oasys lenses, utilizing an internal PVP wetting agent rather than a surface treatment to stabilize the tear film. This helps keep the eyes hydrated during work with digital screens and offers continuous visual accuracy. 

Hydraluxe

Applied to the Acuvue Oasys 1 Day lenses, this technology is designed with tear-like molecules and breathable silicone. It is formulated with the molecule PVP in combination with a fine polymer network, that works under similar attributes to the mucins in tears to moisturize the eyes with every blinking motion, reducing symptoms of tired and dry eyes.

HydraMax

The silicone hydrogel formulation applied to Acuvue Vita lenses does not require a coating but rather relies on a network of lipophilic silicones that are hydrated and installed in long chains of PVP. A maximum amount of the PVP is embedded to interact with the eye’s lipids and maintain hydration.

Alcon

Blink-Activated Moisture

The hydrating agent PVA is built into Dailies AquaComfort Plus lenses, freely moving in the matrix. Blinking releases the PVA in small amounts to moisturize the ocular surface and stabilize the tear film.  

Smartshield

A thin hydrophilic layer applied to the Air Optix range to provide consistent resistance against lipid deposits during wear, as well as cosmetic residue. The surface area is bonded to the lens to create a smooth lens surface while the silicone core allows optimum oxygen transmission. 

SmarTears and Water Gradient

These technologies are applied to Dailies Total 1 to create a soft surface gel that remains wettable. SmarTears utilizes phosphatidylcholine as an active ingredient, found in tears, that slowly release from the lens to stabilize the tear film. In addition, the water gradient technology enables a water content transition of 33% in the core to 80% on the inner and almost 100% on the outer lens surface. These technologies create a highly breathable water gradient silicone hydrogel, that reduces the evaporation of water throughout the day and prevents contact lens dryness.

Discussing contact lens options with patients

Optometrists have a large variety of contact lenses with different materials, modulus, technologies and attributes to offer the patient. When communicating to patients about these options, there can be several points of consideration. As optometrists, we are aware that the right measurements and any eye health risks, such as allergies or previous eye infections, will affect the choice of the correct lens type for our patients. Personal preference of contact lens manufacturers and brands may also contribute to the lens recommendation, and these can depend on their individual lifestyles, previous experiences and values. 

In addition to the careful examination of their ocular history and health, discussions about the patient’s expectations and fears are further factors for consideration. If their work is air-conditioned, and involves long hours they may benefit from a low water content silicone hydrogel lens such as Biofinity, while those surrounded by debris or who have an oily tear film may benefit from Alcon’s Smartshield technology or lenses with less raw silicone. Let’s also not forget patients who spend long hours in front of digital devices who may benefit from the Hydraclear Plus technology found in Acuvue Oasys.

For wearers that have previously experienced struggles during insertion or removal of the lens, the higher modulus of certain silicone hydrogels may be beneficial, whereas those who felt previous silicone hydrogel lenses were uncomfortable and irritating on their eye may favour a silicone hydrogel lens with a lower modulus.

Discussing their hobbies, from playing video games to sports like swimming, can ensure a tailored decision around water content and the right modality, respectively. Additionally, these conversations can help to build a trusting relationship with the patient. 

Communication during a contact lens fitting or check-up appointment is key to ensure the patient feels comfortable to voice any concerns and feels free to ask questions. With an attentive and open attitude, you will be able to ensure your patient’s eye health during contact lens wear. 

Patients may inform themselves about the complex technologies and features of contact lenses through independent research before and after their appointments. Online retailers often supply helpful guides to offer assurance to their customers about the information given by the optometrist. Familiarisation with the information on the web and using it as examples during a discussion can ensure the patient feels secure in their choice.

Roshni Patel BSc (Hons) MCOptom qualified as an Optometrist in 2004. She is a member of the Association of Optometrists and is the Professional Services Manager at Lenstore where she is responsible for supporting and guiding all departments from a clinical standpoint.