Sterile. For daily, extended wear and disposable soft contact lenses. Opti-Free Express Rewetting Drops moistens your lenses and helps to remove particulate material that may cause irritation and/or discomfort. Opti-Free Express Rewetting Drops, an effective thimerosal-free formula, is especially formulated for use while wearing daily, extended wear and disposable soft (hydrophilic) contact lenses.