Pharmacology
Diagnostic and therapeutic medications, instillation technique, and side effects.
Diagnostic Drops the Assistant Uses Daily
Mydriatics/cycloplegics (red caps) — tropicamide (short-acting dilation), phenylephrine (adrenergic dilation without cycloplegia; 10% used cautiously for cardiac/BP effects), cyclopentolate (pediatric cycloplegic refraction) and atropine (strongest and longest — days; watch children for anticholinergic toxicity: flushing, fever, fast heart rate). Standard adult dilation pairs tropicamide + phenylephrine — sphincter blocked and dilator stimulated at once. Always screen for shallow anterior chambers per protocol and document pupil status before dilating.
Topical anesthetics — proparacaine and tetracaine: onset in seconds, duration 10–20 minutes. Never dispensed to patients — repeated use melts corneas. For tonometry, anesthetic goes in before or with the fluorescein.
Stains — fluorescein highlights epithelial defects (green under cobalt blue) and draws the applanation mires; IV fluorescein runs angiography. Lissamine green and rose bengal stain devitalized cells — the dry-eye workup dyes.
Instillation technique — one drop in the inferior fornix, tip touches nothing, five minutes between different drops, drops before ointment. Teach punctal occlusion to limit systemic absorption (especially beta blockers).
Glaucoma Drug Classes
The assistant recognizes classes, mechanisms, and red-flag interactions; the physician prescribes.
| Class (stem) | Example | Mechanism | Watch for |
|---|---|---|---|
| Prostaglandin analogs (-prost) | Latanoprost | ↑ uveoscleral outflow | Iris darkening, lash growth; evening dosing |
| Beta blockers (-olol) | Timolol | ↓ aqueous production | Asthma/COPD, bradycardia — systemic absorption |
| Carbonic anhydrase inhibitors | Dorzolamide, oral acetazolamide | ↓ aqueous production | Sulfa allergy |
| Alpha agonists | Brimonidine | ↓ production, ↑ outflow | Fatigue, dry mouth; avoid in infants |
| Miotics | Pilocarpine | ↑ trabecular outflow; pulls iris off the angle | Brow ache, dim vision; angle-closure use |
| Rho-kinase inhibitors | Netarsudil | ↑ trabecular outflow | Redness, cornea verticillata |
Emergencies — in acute angle closure the physician may add oral/IV acetazolamide and hyperosmotics (mannitol) to crash the pressure while definitive care is arranged.
Name stems are fast clues — -olol, -prost, -caine (anesthetics), -floxacin (fluoroquinolone antibiotics).
Therapeutics, Side Effects, and Bottle Discipline
Antibiotics — erythromycin ointment for lids and surface prophylaxis; fluoroquinolone drops for serious bacterial keratitis. Recognize, don't prescribe.
Steroid drops — powerful and double-edged: IOP spikes in steroid responders, posterior subcapsular cataract with time, and fuel for herpetic and fungal infection. Physician-managed with monitoring; refill requests get routed, never rubber-stamped.
Allergy drops — itching is the hallmark symptom; dual-action antihistamine/mast-cell stabilizers (olopatadine) treat now and prevent later.
Artificial tears — frequent dosers and severe dry eye do better preservative-free; benzalkonium chloride (BAK) irritates with heavy use.
Bottle discipline — the tip is sterile until it touches anything; date bottles per policy; discard expired or contaminated stock. Contaminated diagnostic bottles have caused clinic outbreaks.
The systemic connection runs both ways — drops drain through the nasolacrimal duct into the bloodstream (hence punctal occlusion), and systemic drugs mark the eye: hydroxychloroquine (retinal screening), tamsulosin (floppy iris at surgery), anticoagulants (bleeding risk), steroids by any route.