The Evolve system aims to give the best of both worlds - the sensitivity of unit dose preservative-free vials in a convenient eye drop bottle. Evolve® is a ground breaking technology that delivers a preservative-free, sterile eye drop from a multi-dose container. Removing preservatives from eye health products generally benefits patients' long term treatment. Evolve Hypromellose is both preservative-free and phosphate-free, ideal for sensitive eyes and frequent users. Evolve Hypromellose can be used for up to 3 months once opened. The long-lasting feature means Evolve Hypromellose is ideal for infrequent users.