Abstract: Disclosed is the use of a mist of a pharmaceutical composition for ophthalmic delivery of a protein or peptide active pharmaceutical ingredient, a related method of treatment and a device useful in implementing the use and method. Disclosed is also the use of a mist for ophthalmic delivery of a pharmaceutical composition including a highly irritating penetration enhancer and an ophthalmically acceptable carrier, a related method of treatment and a device useful in implementing the use and method. Disclosed is also a device for ophthalmic administration configured to direct a mist of a pharmaceutical composition to the eye only when the eye is open. Disclosed is also a self-sterlizing device for ophthalmic administration. Disclosed is also a device and a method for increasing the bioavailability of an ophthalmically administered API in a pharmaceutical composition.