Optometry is not practiced in isolation from the rest of medicine. The medications patients take for systemic conditions can profoundly affect the eye—and ophthalmic medications can cause systemic effects. Paraoptometric staff who understand these interactions provide better care, take more accurate health histories, and help prevent adverse events. This topic appears on both CPO and CPOA certification exams.
Why the Medication History Matters
During intake, paraoptometrics collect the medication history. This section should be thorough—including prescription medications, over-the-counter drugs, vitamins, and herbal supplements. Items to specifically document:
- All prescription medications — Include dose and frequency when possible
- OTC medications — Aspirin, NSAIDs, antihistamines, decongestants
- Vitamins & supplements — Vitamin E, ginkgo, fish oil affect bleeding risk
- Recent changes — New medications may explain new symptoms
- Drug allergies — Distinguish true allergy from intolerance/side effect
- Systemic conditions — Linked conditions determine which medications are high-priority
Systemic Medications with Significant Ocular Effects
- Hydroxychloroquine (Plaquenil) — Rheumatoid arthritis, lupus, malaria — Bull's eye maculopathy—irreversible retinal damage — Annual OCT + visual field after 5 years; HVF 10-2; mfERG if high risk — high
- Amiodarone (Cordarone) — Cardiac arrhythmia — Vortex keratopathy (whorl-like corneal deposits), optic neuropathy — Baseline and annual exam; corneal deposits often asymptomatic — medium
- Isotretinoin (Accutane) — Severe acne — Severe dry eye, meibomian gland atrophy, decreased night vision — Document dry eye symptoms at baseline; lubricant therapy often needed — medium
- Steroids (systemic prednisone) — Inflammation, autoimmune conditions — Posterior subcapsular cataracts (PSC), elevated IOP, increased infection susceptibility — Regular IOP checks in patients on chronic systemic steroids — medium
- Tamoxifen — Breast cancer treatment/prevention — Crystalline macular deposits, retinal toxicity at high cumulative doses — Baseline and annual retinal exam with OCT — medium
- Digoxin — Heart failure, atrial fibrillation — Yellow-green visual disturbances (xanthopsia), blurred vision at toxic levels — Visual symptoms may indicate toxicity—alert doctor immediately — high
- Oral contraceptives / Estrogens — Contraception, menopause management — Dry eye, contact lens intolerance, increased clotting risk (CRVO risk) — Note at health history; affects contact lens candidacy discussions — low
- Antihistamines (systemic: diphenhydramine, loratadine) — Allergies, sleep aids — Dry eye (anticholinergic effect), blurred vision, angle-closure risk in predisposed eyes — Document for dry eye workup; caution in narrow-angle patients — medium
Ophthalmic Medications with Systemic Effects
Eye drops are absorbed systemically through the nasolacrimal drainage system. The nasal mucosa provides rapid, highly bioavailable absorption—bypassing hepatic first-pass metabolism. This is why even "local" eye drops can have significant systemic effects:
- Timolol (beta-blocker glaucoma drop) — Bradycardia, hypotension, bronchospasm, CNS effects, masks hypoglycemia — Asthma, COPD, certain cardiac arrhythmias, severe bradycardia
- Tropicamide / Phenylephrine (dilation drops) — Tachycardia, hypertension (phenylephrine especially at 10%); blurred vision, urinary retention in elderly males — 10% phenylephrine: severe cardiovascular disease; use 2.5% instead
- Atropine (cycloplegic) — Tachycardia, dry mouth, flushing, urinary retention, CNS effects (especially in children) — Narrow-angle glaucoma, pyloric stenosis, cardiac arrhythmias
- Brimonidine (alpha-2 agonist for glaucoma) — CNS depression—serious sedation risk in infants/young children — Children under 2 years; patients on MAO inhibitors
- Pilocarpine (cholinergic miotic) — Increased sweating, nausea, bradycardia, increased secretions at high doses — Caution with active GI disease, urinary obstruction
Nasolacrimal Occlusion (NLO) to Reduce Systemic Absorption
Instruct patients on NLO technique to minimize systemic absorption of drops with significant side effect profiles: