All ophthalmic ointments or drops are not created equal. The most common eye medications have nothing added and are a saline solution, have an antibiotic or several antibiotics added, or an antibiotic with an added steroid.
Here are several important points to keep in mind regarding eye medications:
1. Ophthalmic drops only have a life of an hour or so in the eye before the medications are flushed out. Ointments only last a little longer. Therefore frequent administration is the key to treatment of any significant eye disorder.
2. Administration of the wrong ointment or drops could seriously endanger your horse’s eye. Eye medications other than artificial tears (saline solution or saline in a gel base) should only be used under the guidance of your vet, who has diagnosed the problem properly prior to suggesting treatment.
3. In most cases, you can safely use a straight antibiotic ointment in a seemingly irritated eye. Steroid containing ointments should only be used under the guidance of your veterinarian. Steroids administered in the eye can cause severe worsening of corneal ulcers, resulting in corneal perforation and the loss of vision.