A pharmaceutical composition comprising a semifluorinated alkane of formula (I): F(CF2)n(CH2)mH, wherein n is an integer from 4 to 6, and m is an integer from 5 to 8, for use in the treatment or prevention of a disease or condition relating to an ocular surface of an eye of an individual, wherein the individual is a contact lens wearer, and wherein the contact lens is a hydro gel contact lens and the composition is administered topically to a surface of the eye of the individual before the contact lens is inserted to the eye of the individual and/or during contact lens wear and/or after the contact lens has been removed from the eye of the individual, or wherein the contact lens is a silicone hydrogel contact lens and the composition is administered topically to a surface of the eye of the individual after the contact lens has been removed from the eye of the individual.