What action can minimize systemic absorption when administering ophthalmic medication?

Minimizing systemic absorption of ophthalmic medications is important to reduce potential side effects and enhance the medication’s local efficacy. Applying pressure to the inner canthus, situated at the corner of the eye closest to the nose, after instillation helps to occlude the nasolacrimal duct, which decreases the drainage of the medication into the systemic circulation.

When pressure is applied after drops are administered, it effectively reduces the amount of medication that enters the vascular system through the tear ducts, thereby increasing the local action intended in the eye. This practice is particularly relevant when using medications that are known to have systemic effects or when a patient is using multiple drops for eye treatment, as it helps maintain the medication's therapeutic concentration in the target area for a longer duration.

Waiting 5 minutes before instilling drops in the other eye does allow time for the first medication to be absorbed and can prevent dilution of the first medication; however, it does not actively minimize systemic absorption in the way that applying pressure does.