Addressing discomfort through contact lens innovation
Engineers spent two decades developing a new generation of contact lenses, Dailies Total1, to address the issue of discomfort users experience with existing silicone hydrogel lenses.
May 21, 2014
Graduate student Evan Sullivan switched to contact lenses, as they give him the freedom to enjoy his college lifestyle, work out at the gym and spend time on the beach without having to worry about his glasses while he is there.
Evan Sullivan, Graduate Student
What he didn’t expect was to find himself in front of an eye care professional with uncomfortable contact lenses. “My lenses felt uncomfortable, no matter what I did,” recalls Sullivan. “I tried everything. I wanted to wear contact lenses because I felt more free with them, but these contact lenses weren’t working for me.”
Sullivan’s contact lens experience is not as uncommon as you might think. Contact lens discomfort is the number one reason for contact lens dropout. Some people find their lenses begin to feel dry and irritating toward the end of the day.
“There is clearly a problem when people tell you they get a better visual experience with contact lenses, but still decide to stop wearing them and instead go back to wearing spectacles due to the lack of comfort,” said Franck Leveiller, Head of Research and Development for Vision Care at Alcon.
To tackle this problem, engineers spent more than a decade developing Dailies Total1® water gradient contact lenses, with the aim that it should be as comfortable as wearing no lens at all.
They came up with a unique water-gradient material, which allows for a measurable change in water content throughout the lens. At its core, the lens features a highly breathable1, silicone hydrogel material with a low water content of 33%, so more oxygen is allowed through the lens, for healthy looking eyes.
The lens transitions to an ultra-soft surface gel layer made up of more than 80% water2, nearly the same as the surface of the eye, which helps minimize friction with the delicate tissues of the eye.
The novel composition of the lens helps address the trade-off in other silicone hydrogel lenses, between higher silicone content – delivering greater oxygen flow – and a higher water content, a factor in comfortable contact lens wear.
“The ability to vary the concentration of water and silicone throughout the lens, providing the right combination of oxygen for breathability1 and water content, took years to achieve,” Mr. Leveiller said.
“In the end, there were two real breakthroughs. One was in the material science that went into the lens and the other was in the manufacturing know-how we needed to make the lenses.”
Producing the contact lenses required an innovative, multi-step process to surround the silicone hydrogel core material with an ultra-soft surface.
Feedback from users of the Dailies Total1® contact lenses has been positive. “The first time I wore the contact lenses was from 8am to 11pm,” says Sullivan. “These have really worked for me.”