Major Pharmaceuticals Sodium Chloride Hypertonicity Ophthalmic Solution, 5% can offer effective daytime temporary relief when you suffer from corneal edema. This solution is available without a prescription, but should be used upon recommendation by an eye care professional. This product contains no mercurial compounds such as Thimerosal Follow up with preservative-free Sodium Chloride Hypertonicity Ophthalmic Ointment, 5% for nighttime use (to be applied either every 3 to 4 hours, or as directed).