Final answer:
The most appropriate action when performing eye instillation is to apply the medication onto the conjunctival sac.
Step-by-step explanation:
The most appropriate action when performing eye instillation is to apply the medication onto the conjunctival sac.
The conjunctival sac is the space between the eyelid and the eyeball, and it is lined with a thin, moist membrane called the conjunctiva. Applying the medication onto the conjunctival sac allows it to be absorbed into the tissues and fluids of the eye, providing effective treatment.