These<unk> s are packaged for single use, without preservatives<unk> s or<unk> s are liquid<unk> s applied directly to the surface of the eye, particularly the human eye, usually in small amounts such as a single<unk>  or a few<unk> s.<unk> s usually contain saline to match the salinity of the<unk> s containing only saline and sometimes a lubricant are often used as artificial tears to treat dry eyes or simple eye irritation such as itching or redness.<unk> s may also contain one or more medications to treat a wide variety of eye diseases. Depending on the condition being treated, they may contain steroids, antihistamines, sympathomimetics, beta receptor blockers, parasympathomimetics, parasympatholytics, prostaglandins, nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, antifungals, or topical anesthetics.<unk> s have less of a risk of side effects than do oral medicines, and such risk can be minimized by occluding the lacrimal punctum (i.e. pressing on the inner corner of the eye) for a short while after instilling<unk> s. Prior to the development of single-use pre-loaded sterile plastic applicators,<unk> s were administered using an<unk> per, a glass pipette with a rubber bulb.
Eye drop
Ear drop
Protruding ear
Red eye 
Enophthalmos
Christmas eye
Lagophthalmos
Cryptophthalmos