Proper eye drop instillation is both a clinical skill for paraoptometric staff and a critical patient education topic. Even the most effective ophthalmic medication fails if it is instilled incorrectly—missing the eye, touching the tip and contaminating the bottle, or being washed away before absorption. The CPO and CPOA exams test your knowledge of correct technique, patient instruction, and medication safety principles.
Why Drop Technique Matters Clinically
Efficacy
A drop that misses the eye or is immediately blinked away provides no therapeutic benefit. Correct technique ensures the medication reaches the intended tissue.
Safety
Touching the bottle tip to the eye introduces bacteria directly into the container, contaminating future doses and risking infection.
Systemic Absorption
Drops absorbed through the nasolacrimal system bypass hepatic metabolism and can reach systemic circulation at significant concentrations—making technique critical for drops with cardiac or pulmonary effects.
Step-by-Step Eye Drop Instillation
Wash and Dry Hands
Soap and water for 20 seconds; dry thoroughly. Prevents bacterial transfer to the eye and bottle.
N: 1
Check the Medication
Confirm the correct eye (OD = right, OS = left, OU = both), correct medication, and that it is within the expiration date and has not been open too long.
N: 2
Shake if Required
Some suspensions (e.g., prednisolone acetate, ketorolac ophthalmic) require shaking before instillation. Follow instructions.
N: 3
Position the Patient
Head tilted back or lying supine. Either position allows gravity to assist drop placement into the conjunctival pocket.
N: 4
Create the Conjunctival Pocket
Gently pull the lower lid down with the non-dominant hand's index finger, exposing the inner conjunctival surface (cul-de-sac). This is where the drop should land.
N: 5
Position the Bottle
Hold the bottle between thumb and forefinger, about 1–2 cm (½ inch) above the eye. The patient should look up or away from the bottle tip.
N: 6
Instill One Drop
Squeeze the bottle gently until one drop falls into the lower conjunctival pocket. Do not allow the bottle tip to touch the eye, lashes, or lids.
N: 7
Release the Lid and Close the Eye
Release the lower lid. Have the patient close the eye gently for 1–2 minutes. Do not squeeze or blink—this pumps the drop into the nasolacrimal system prematurely.
N: 8
Apply Nasolacrimal Occlusion
With eyes closed, apply gentle pressure to the inner corner of the eye (over the punctum/lacrimal sac) for 1–2 minutes. This reduces systemic absorption by blocking drainage.
N: 9
Blot Excess
With a clean tissue, gently blot any excess drop from the lid margin without rubbing.
N: 10
Managing Multiple Eye Drops
Many patients—especially glaucoma patients—use multiple drops. The order and timing of instillation matters:
- Wait 5 minutes between drops — The conjunctival cul-de-sac holds ~30 µL. A single drop is 30–50 µL. Without waiting, the second drop washes out the first.
- Apply drops before ointments — Ointments create a barrier that prevents drops from reaching the conjunctival surface. Always instill drops first, then ointment.
- For suspensions (cloudy drops): shake well — Active drug particles settle to the bottom. Without shaking, the first portion of a suspension bottle has mostly vehicle, not medication.
- Refrigerated drops: allow to reach room temperature — Cold drops increase reflex tearing, washing the medication from the eye. Allow refrigerated drops to warm to room temp for 5–10 minutes before instilling.
Special Considerations
- Children — Use two-person technique: one restrains, one instills, For uncooperative children, drops can be instilled at the medial canthus with eye closed—the drop enters when they open the eye, NLO is especially important in children to minimize systemic cycloplegic/mydriatic absorption
- Elderly Patients — Arthritis may make self-administration difficult—offer auto-drop devices, Cognitive impairment may require caregiver education, Tremors: lying down and having caregiver instill is safer than self-administration standing
- Contact Lens Wearers — Remove soft lenses before instilling drops (preservatives absorbed into lens), Wait 10–15 minutes before reinserting, Some drops designed as lens-compatible—check with doctor
- Patients on Anticoagulants — Press gently at inner canthus—avoid vigorous pressure that could cause periorbital bleeding, Limit manual manipulation of lids, NLO should be gentle