The invention relates to a composition containing, as an active substance, ectoine, hydroxyectoine and/or salts, esters or amides of these compounds, for the treatment and/or prophylaxis of eye diseases that are associated with a disturbance of the tear film. In particular, this can be keratoconjunctivitis sicca. Unexpectedly, these compounds have been shown to be able to prevent rupturing of the outer lipid layer of the tear film and thus avoid an undesired rapid evaporation of lacrimal fluid.
