Composition containing quaternary ammonium compounds in which the nitrogen atom is substituted by at least one alkyl group having at least 12 carbon atoms, the composition including at least 20% in weight by weight of the total composition, of ammonium halides in which the nitrogen atom is substituted by at least one alkyl group having at least 14 carbon atoms and more than 5%, preferably more than 7% in weight by weight of the total composition, of ammonium halides in which the nitrogen atom is substituted by at least one alkyl group having at least 16 carbon atoms. Ophthalmic oil-in-water emulsions containing such compositions, the ophthalmic emulsions being useful for eye care or for the treatment of eye conditions are also disclosed.