Unity BioSync Contact Lenses With HydraMist

By Linda Conlin, ABOC, NCLEC

Release Date: February 1, 2020

Expiration Date: January 10, 2023

Learning Objectives:

Upon completion of this program, the participant should be able to:

  1. Learn about the unique visual challenges facing us due to the dynamically connected modern lifestyle.
  2. Learn about the visual challenges caused by the physiological changes of the aging eye.
  3. Learn about an adaptive lens technology that changes with the digitally connected wearer's age-related vision requirements.

Faculty/Editorial Board:

Linda Conlin Linda Conlin, ABOC, NCLEC

Credit Statement:

This course has been approved for one (1) hour of Ophthalmic Level II continuing education credit by the National Contact Lens Examiners (NCLE). Course CTWJHI103-2

Small enough to fit on the tip of a finger, there's a new way to provide exceptional comfort and clear vision to contact lens patients. Unity Bio- Sync Contact Lenses with HydraMist are premium silicone hydrogel daily disposable contact lenses with all new HydraMist technology. BioSync with HydraMist is designed for optimum oxygen delivery while maintaining wettability and a healthy tear film. The silicone hydrogel material used in these lenses provides some of the high- est levels of oxygen transmittance. In addition to the low maintenance of a daily disposable lens and high oxygen transmittance, Unity Bio- Sync lenses offer HydraMist technology that allows the contact lenses to mimic the natural tear film of the eye to ensure consistent mois- ture for all-day comfortable wear. Here, learn how and why Unity BioSync lenses benefit patients and practices.

BioSync with HydraMist technology addresses the intrinsic relationship between water content, oxygen permeability and comfort in a silicone hydrogel lens


What makes silicone hydrogel lenses different from lenses made from hydrogel only? Introduced in the 1960s, soft and with high water content hydrogels were a great improvement in comfort and oxygen delivery over hard (PMMA) lenses. Those improvements weren't quite good enough, however. The higher water content decreased the refractive index of the lenses and made them thicker, which reduced oxygen delivery to the cornea. The higher the water content, the more difficult it is for oxygen to get to the corneal surface, which gets most of its oxygen from the atmosphere. What's more, the higher water content of the lenses causes them to evaporate quickly and dry out. The lenses then absorb water from tears, resulting in eye dryness that reduces wearing time. When patients needed to wear their lenses for perhaps up to 15 hours, many had to use rewetting drops or take the lenses off for a time. To combat lens dryness, contact lens manufacturers embedded wetting agents in the lenses, but those leached out over time.

The year 1999 saw the debut of silicone hydrogel lenses. Oxygen is highly soluble in silicone, but it is hydrophobic (tends to repel water). That characteristic results in low wettability, the dispersion of a liquid across a surface. Wettability is measured by the wetting angle, the angle formed between a drop of liquid and a surface. High wetting angles over 90 degrees indicate poor wettability because the drop maintains its shape. Low wetting angles of less than 90 degrees indicate better wettability because the drop spreads across the surface. Combining silicone with hydrogel resulted in a more hydrophilic (attracted to water) material with better wettability, but more wettability and oxygen transmission were needed. The HydraMist technology with BioSync lenses creates a mucin-like wetting surface on the underlying lens material. More porous than regular hydrogel lenses, silicone hydrogels allow even more oxygen to reach the cornea.


Let's look at how silicone hydrogel lenses deliver oxygen to the cornea versus hydrogel only. Diffusion is the movement of molecules from an area of higher concentration to a lower one. Solubility is the amount of substance dissolved in a solvent. Hydrogels deliver oxygen through solubility (oxygen dissolved in the water content of the lens). Silicone hydrogels deliver oxygen through diffusion (oxygen passing through the lens). The amount of oxygen that passes through a lens over a specific time and pressure difference is measured as Dk. The measurement Dk/t is that measurement accounting for lens thickness. The higher the Dk, the better the oxygen delivery. Silicone hydrogel materials possess Dk/t values of 110 to 175, which is six times more permeable than conventional hydrogel contact lenses. Put simply, they deliver more oxygen to the cornea.

Hypoxia is a condition in which a region of tissue in the body; in this case, the cornea, is deprived of adequate oxygen supply. Any barrier to the cornea receiving atmospheric oxygen, such as a contact lens, affects corneal metabolism. Corneal hypoxia can result in ocular surface inflammation, corneal swelling, microcysts, limbal hyperemia (filling of the blood vessels at the limbus), neovascularization (encroachment of blood vessels into the cornea) and changes in the composition of the tear film. The compromised cornea is then susceptible to infection. The best contact lens, to be certain, is the lens that delivers the most oxygen.

There are more benefits to silicone hydrogel lenses. The high oxygen transmissibility allows for longer wearing time. The modulus (stiffness or rigidity of the materials) is over twice that of hydrogels, for easier handling. Several clinical studies have found silicone hydrogel lenses result in fewer overall symptoms of dryness and discomfort. Comfort increased as end-of-day dryness, redness and discomfort, as well as the frequency and intensity of dryness symptoms were decreased.


Although combined with hydrogel material to improve wettability, exposed areas of silicone in silicone hydrogels maintained their hydrophobic characteristics for less than optimum wettability. Contact lens wettability is critical to contact lens comfort for several reasons. A good wetting surface will prevent changes to the undersurface of the eyelid as it blinks over the contact lens. Wettability also affects the accumulation of deposits on the lens. A lens with poor wettability will result in dry patches on the lens that increase deposits of lipid and denatured protein from the tears. These deposits result in less comfort, reduced clarity of vision and increased inflammatory responses. What's more, wearing any contact lens disrupts the lipid layer of the tear film leading to evaporation of the aqueous layer and therefore, dryness.

Compare tear film: no lens - uncoated lens - lens with HydraMist

VSP partnered with contact lens technology company Tangible Science and contact lens manufacturer Visco Vision Incorporated to develop the BioSync silicone hydrogel daily contact lens with HydraMist technology. HydraMist technology features an advanced polymer that was exclusively developed by Tangible Science for silicone hydrogel contact lenses. The polymer is designed to attach to the surface of Unity BioSync contact lenses for a full day of wear, to improve lens hydration and provide a durable, comfortable experience for contact lens users. By combining BioSync contact lenses with HydraMist technology, there is a contact lens that maintains the correct balance of oxygen and moisture for eye health and comfort. HydraMist is a 90 percent water polymer that mimics the eye's natural tear film. It was developed from a polymer that has been used in wound care management and ocular lubricants for decades and is known to improve lens surface wettability, increase lubricity, improve tear breakup time (the interval between instillation of fluorescein and appearance of the first dry spots on the cornea—the shorter the interval, the greater the tear instability) and reduce protein and lipid deposition on the lens. It is permanently bonded to the surface of the contact lens, effectively creating a mucin-like wetting surface on the underlying lens material, encapsulating the contact lens with a hydrophilic shell and shielding it from the ocular surface and tear film.

The first part of the process is to activate the lens surface so that it will covalently bond to the HydraMist polymer, forming a permanent bond. Once activated, polymers are added to the blister pack during the autoclave process. Then the active lens is placed in the HydraMist polymers, which permanently bond to the lens surface. The resulting lens is completely encapsulated with the HydraMist polymers resulting in a surface with optimal wettability, lubricity, tear film stability and resistance to deposits.

In addition to improved wettability, HydraMist improves contact lens lubricity. Lubricity is a measure of the friction a contact lens exerts on the cornea. A contact lens' lubricity or "slipperiness" determines how it moves on the eye and how the lids blink over the surface. When you consider that the average person blinks up to 14,000 times every day, there is considerable potential contact lens friction that may lead to a decrease in lens comfort and wearing time. Poor lubricity has been linked to contact lens-associated red eye and other lens issues. With both wettability and lubricity related to friction, it's easy to understand that less friction means more comfort and better eye health.

Tear Film Layers: normal - with uncoated CL - CL with HydraMist

Deposit resistance is a lower tendency of protein, lipid and other tear components to adhere to a lens surface. Deposits on contact lenses result in a foggy, hydrophobic surface. Proteins in the tear film are present in their natural state and have antibacterial properties to help protect the eye. However, they can become denatured, that is, altered through external stress such as a contact lens, and their antibacterial properties diminish. This can induce an inflammatory response in the eye, resulting in irritation. The outermost layer of the tear film is the oily lipid layer. It functions to provide an optically smooth surface over the cornea and prevent tear evaporation. Like proteins, lipids, when deposited on contact lenses, can also change function by oxidation and degradation, thereby reducing lens wettability and may impact comfort and vision over time. Limiting lipid deposition on contact lenses promotes tear film stability. Clearly, lenses that maintain wettability and resist protein and lipid deposits are likely to remain moist and comfortable on the eye.


HydraMist features unique moisture-retaining polymers for an increased level of hydration throughout the day. HydraMist aims to improve the biocompatibility of the contact lens material and the surface of the eye to enhance the overall wearing experience for the contact lens wearer. BioSync lenses offer a Dk/t value of 150, allowing more oxygen to get to the eyes, which is critical in preserving eye health. Add to that lubricity, deposit resistance and UVA/UVB attenuation with the convenience of a daily disposable lens, and you have all-day comfort, clear vision and healthier eyes—the ideal contact lens wearing combination! (Note: UV-absorbing contact lenses are NOT substitutes for protective UV-absorbing eyewear such as UV-absorbing goggles or sunglasses because they do not completely cover the eye and surrounding area. Patients should continue to use UV-absorbing eyewear as directed.)


Clinical trials are conducted to create a fair and balanced way of testing a product's performance. Before launching the Unity BioSync with HydraMist contact lenses, VSP contracted an independent research consultant to conduct a multicenter masked, randomized crossover clinical trial. A crossover study is a type of clinical trial in which the study participants receive each treatment in random order. With this type of study, every patient serves as his or her own control. The purpose of the clinical trial was to compare the short-term clinical performance and wearer and practitioner acceptability of spherical Unity BioSync with HydraMist daily disposable contact lenses in comparison with the subjects' habitual daily disposable contact lenses and a series of comparative daily disposable contact lenses.

In a group of 70 subjects, the Unity BioSync with HydraMist daily disposable contact lenses performed well when compared to both the subjects' habitual contact lenses and the comparative lenses that were worn during the study period. Subjects rated BioSync with HydraMist lenses 9 out of 10 for overall vision, 9 out of 10 for initial comfort, and 8 out of 10 for overall comfort.

Eyecare practitioners noted more benefits of daily disposable lenses, too. According to a survey with 300 ECPs in the United States, United Kingdom and Japan during November 2017, reported in the journal Contact Lens & Anterior Eye, ECPs rated the following statements: "Silicone hydrogel 1 day lenses satisfy today's patients' demanding lifestyles" (93 percent agreement); "Silicone hydrogel 1 day lenses are the best choice to safeguard my patients' eye health related to contact lens wear" (92 percent); "Silicone hydrogel 1 day lenses provide the best benefits to my patients" (92 percent); "Silicone hydrogel 1 day lenses provide better long-term eye health for my patients than hydrogel 1 day lenses" (91 percent); "Silicone hydrogel is the healthiest lens material for my daily disposable patients" (90 percent); and "Silicone hydrogel 1 day lenses provide a better wearing experience for my patients than hydrogel 1 day lenses" (90 percent).


According to a recent study, daily disposable contact lens wearers have the highest replacement compliance compared to patients with other lens replacement schedules. Eightyeight percent of daily disposable lens wearers replace their lenses on schedule as compared to 48 percent of wearers on a two-week replacement schedule and 72 percent of wearers on a monthly schedule. That means most daily disposable wearers have a fresh lens every day.

For established contact lens wearers, eyecare practitioners should constantly promote innovations in contact lenses. Rather than just refit that patient into the same monthly lens they have worn for the past four years, offer new products, and help patients consider daily disposable lenses by discussing and offering them healthier and more convenient alternatives. If patients wear lenses only a few times a week or a few times a month, a monthly or biweekly lens is likely to sit in a solution that is days or weeks old. Patients are more likely to forget when the lenses were last replaced. Daily disposables offer convenience for these patients. Patients who travel frequently benefit from replacing bulky solutions with daily disposables that are easy to pack. It's also easy to carry spare lenses in the event of extended travel, or for anyone who might lose a lens.

BioSync with HydraMist technology for improved wettability, lubricity and resistance to protein and lipid deposits

Keep up with the modern contact lens market. Sales of daily disposable contact lenses are growing. The research firm GfK reported that from June to November 2015, daily contact lens sales accounted for 31 percent of U.S. soft contact lens dollar sales—up from 16 percent in the same period four years earlier. At the same time, sales of weekly lenses dropped from 44 percent of sales to 28 percent in the same four-year time frame. Monthly lenses remained flat, representing 40 percent of sales in 2015 versus 39 percent in 2011. This is a clear indication that the contact lens consumer is opting for the comfort and convenience of daily disposable lenses.

Most patients purchase based on value. Value is a combination of price and benefits. In contact lenses, mention the health benefits, the no-cleaning convenience, the great feel of that fresh lens every day, and more patients than you expect will upgrade to daily disposable contact lenses. And don't forget to mention the high-value rebate available for an annual supply of Unity BioSync lenses, to add even more value to a great contact lens choice.

Doctors should prescribe an annual supply of contact lenses in front of the patient. Patients are more likely to do as the doctor recommends in the exam room. When a patient purchases an annual supply of contact lenses, they have a tendency to stay on the prescribed wearing schedule, as studies have shown. They will return for their annual eye exam at a shorter interval than if they purchase contacts on a three- to six- month schedule. If pricing is a concern, show patients the amount they can save for an annual supply with the rebate and their vision benefits. With an annual supply, contact lens purchases stay within the practice for a year because the patient is less likely to purchase more supply online compared to buying only three or six months' supply at a time. What's more, it results in less administrative work for the practice to sell an annual supply—fewer phone calls for orders, less time verifying prescriptions and processing sales.

To summarize, Unity BioSync with HydraMist are daily disposable contact lenses that do not require any maintenance or cleaning. They are made of silicone hydrogel material, which has one of the highest oxygen transmittance levels in contact lenses. They feature HydraMist technology, a proprietary moisture-retaining polymer coating that stabilizes patients' tear film and ensures consistent moisture to the eye during all-day wear. They are competitively priced and come with a rich consumer rebate. Unity BioSync contact lenses with HydraMist let the eyes breathe and maintain a normal moist tear film for healthy eyes and wearing comfort—a winwin for the patient and practice.