Ointments are probably the oldest method of treating dry eye and are still in relatively common use. A small amount of ointment is placed in the eye at night to protect eyes from excessive drying. Daytime use is not practical due to blurring of vision.
The use of ointments is controversial. Some think that it makes the ocular surface less "wettable", meaning regular use may worsen dry eye conditions. Ointments tend to be unpopular with patients except in extreme cases because of the difficulty of applying them and the residue they leave.