ophthalmic administration of medication, the administration of a drug by instillation of a cream, an ointment, or a liquid drop preparation in the conjunctival sac. The correct strength and amount of the drug are selected, and the medication is instilled into the eye or eyes as directed. The order usually specifies O.D. for right eye, O.S. for left eye, or O.U. for both eyes. Ophthalmic preparations are often refrigerated for storage but are given at room temperature. For administration the patient is positioned comfortably, lying back on a bed or examining table or sitting up with the neck hyperextended. The cul-de-sac of the conjunctival sac is exposed by gentle traction on the tissue just below the lower eyelid. The medication is placed into the sac as the patient is instructed to look away from the point of instillation. The dispenser is not allowed to touch the eye, and the medication is not placed directly on the cornea. The eyelid is slowly released, and the patient is asked to roll the eye around a few times to spread the medication over the entire surface of the eye. Applying pressure with the finger at the inner canthus may decrease systemic absorption.
