Perfluorohexyloctane (NOV03, MIEBO), a semifluorinated alkane, is the first drug developed to treat dry eye disease (DED) associated with Meibomian gland dysfunction in a highly effective way. Perfluorohexyloctane is an investigational, proprietary, water-free, non-steroidal, single-component preservative-free eye drop. Perfluorohexyloctane prevents excessive tear evaporation and has the ability to restore tear film balance. The investigational drug has a unique mode of action: it stabilizes the lipid layer for hours to protect the tear film and has the ability to penetrate the Meibomian glands. Perfluorohexyloctane contains 6 perfluorinated carbon atoms and 8 hydrogenated carbon atoms. Perfluorohexyloctane forms a monolayer at the air-liquid interface of the tear film which can be expected to reduce evaporation. The exact mechanism of action for perfluorohexyloctane in DED is not known.