Glaucoma is the leading cause of irreversible blindness worldwide, and topical medications remain the first-line treatment for nearly every form of open-angle disease. The optometric or ophthalmic technician sits at the front of the chain. The tech reviews the medication list, asks about adherence, instills the drop in clinic, counsels the patient on technique, and flags side effects that the doctor needs to know about before the encounter even starts. Knowing what each class does, how it lowers intraocular pressure (IOP), and what to look for is core IJCAHPO-tested content.
This article walks through every major topical glaucoma drug class in clinical use as of 2026, with the generic and brand names you will see daily, the mechanism in plain terms, the side effects that matter, and the technician's role in administration and patient education. Every claim here is consistent with the American Academy of Ophthalmology (AAO) Preferred Practice Pattern for Primary Open-Angle Glaucoma and the IJCAHPO Criteria of Knowledge for the COA, COT, and COMT credentials.
Drug Class Overview
The aim of topical glaucoma therapy is to lower IOP, which reduces the rate of optic nerve damage. There are two ways to lower IOP: decrease aqueous humor production, or increase aqueous humor outflow. Every modern topical glaucoma medication does one or both. The major classes you will encounter:
- Prostaglandin analogs (PGAs): first-line for most patients. Increase uveoscleral outflow.
- Beta-adrenergic blockers (beta-blockers): long-standing second-line. Decrease aqueous production.
- Alpha-2 adrenergic agonists: adjunct therapy. Decrease production and modestly increase uveoscleral outflow.
- Carbonic anhydrase inhibitors (CAIs), topical: adjunct. Decrease aqueous production by inhibiting ciliary body carbonic anhydrase.
- Rho kinase (ROCK) inhibitors: newer class. Increase trabecular meshwork outflow and decrease episcleral venous pressure.
- Cholinergic agonists (miotics): older class, now used selectively. Increase trabecular outflow by ciliary muscle contraction.
- Fixed-combination products: two agents in one bottle to reduce drop burden.
- Latanoprostene bunod: a nitric oxide-donating PGA, technically its own class.
Mechanism by Class
Prostaglandin Analogs
PGAs bind the FP prostaglandin receptor on the ciliary muscle and remodel extracellular matrix in the uveoscleral pathway, increasing the unconventional outflow of aqueous humor. They are the most potent IOP-lowering topicals available, dosed once daily (usually at bedtime), and produce roughly 25-33 percent IOP reduction in most patients. Members in current US use:
- Latanoprost (Xalatan, multiple generics): the original and still the most commonly prescribed.
- Travoprost (Travatan Z).
- Bimatoprost (Lumigan): technically a prostamide; clinically grouped with PGAs.
- Tafluprost (Zioptan): preservative-free unit-dose option.
- Latanoprostene bunod (Vyzulta): latanoprost with a nitric oxide-donating moiety that adds trabecular outflow effect.
Beta-Adrenergic Blockers
Beta-blockers reduce aqueous humor production by blocking beta-2 receptors on the ciliary body epithelium. Typical IOP reduction is 20-25 percent. Dosing is usually twice daily, though gel-forming once-daily formulations exist. The dominant agents:
- Timolol (Timoptic, Timoptic-XE gel-forming, Istalol, multiple generics): 0.25 percent and 0.5 percent strengths.
- Betaxolol (Betoptic-S): a beta-1 selective agent, slightly less potent IOP reduction but safer in patients with reactive airway disease.
- Levobunolol (Betagan), carteolol, metipranolol: less commonly seen now but still in formulary use.
Alpha-2 Adrenergic Agonists
Alpha-2 agonists stimulate presynaptic alpha-2 receptors on the ciliary body, decreasing norepinephrine release and lowering aqueous production. They also modestly increase uveoscleral outflow. IOP reduction is 18-25 percent. Members:
- Brimonidine (Alphagan P): the dominant agent, dosed two to three times daily.
- Apraclonidine (Iopidine): used short-term to blunt IOP spikes after laser procedures, not for chronic therapy due to high tachyphylaxis.
Topical Carbonic Anhydrase Inhibitors
Topical CAIs inhibit carbonic anhydrase II in the ciliary body epithelium, reducing bicarbonate transport and decreasing aqueous production. IOP reduction is 15-20 percent, less than PGAs or beta-blockers. Dosed two to three times daily. Members:
- Dorzolamide (Trusopt).
- Brinzolamide (Azopt): a slightly milkier suspension, often better tolerated for stinging.
Oral CAIs (acetazolamide / Diamox, methazolamide / Neptazane) are reserved for acute IOP spikes or as bridge therapy because their systemic side-effect burden is significant.
Rho Kinase Inhibitors
ROCK inhibitors are the newest class. They act directly on the trabecular meshwork, relaxing actin-myosin tone in trabecular cells to increase conventional outflow, and they also lower episcleral venous pressure. IOP reduction is roughly 15-20 percent as monotherapy, and the effect is additive with PGAs. The current US agent:
- Netarsudil (Rhopressa): once-daily dosing in the evening.
- Netarsudil/latanoprost (Rocklatan): a fixed combination.
Cholinergic Agonists (Miotics)
Pilocarpine contracts the ciliary muscle, which mechanically opens the trabecular meshwork and improves conventional outflow. It is used today mainly for acute angle-closure crises and as an adjunct in pseudophakic eyes where pupillary effects are less problematic. Pilocarpine 1-2 percent (Isopto Carpine) is the most common; a 1.25 percent presbyopia-correcting formulation (Vuity) exists but is not a glaucoma indication.
Fixed-Combination Products
Combining two agents in one bottle improves adherence and reduces washout from sequential drops. Common examples in the US:
- Dorzolamide/timolol (Cosopt, Cosopt PF).
- Brimonidine/timolol (Combigan).
- Brinzolamide/brimonidine (Simbrinza): beta-blocker-free, useful for asthma patients.
- Netarsudil/latanoprost (Rocklatan).
Indications
Topical glaucoma medications are indicated for IOP reduction in:
- Primary open-angle glaucoma (POAG). The most common form and the population for whom PGA monotherapy is typical first-line.
- Ocular hypertension with risk factors warranting treatment based on the Ocular Hypertension Treatment Study (OHTS) framework.
- Normal-tension glaucoma. Treatment goal is to lower IOP from baseline even though it is statistically normal.
- Pseudoexfoliation and pigmentary glaucoma. Often more aggressive disease, frequently requires combination therapy.
- Angle-closure glaucoma after laser peripheral iridotomy or as bridge therapy. Pilocarpine is used acutely; chronic management uses the same agents as POAG.
- Steroid-induced ocular hypertension. When the offending steroid cannot be discontinued, topical IOP-lowering is added.
Side Effects and Contraindications
Prostaglandin Analogs
- Iris hyperpigmentation: permanent darkening of light-colored irides, more common in mixed-color irides over months to years.
- Eyelash growth (hypertrichosis): longer, thicker, darker lashes. Usually cosmetic, sometimes asymmetric if only one eye is treated.
- Periocular skin pigmentation: darkening of the lower lid skin, may resolve with discontinuation.
- Prostaglandin-associated periorbitopathy (PAP): deepening of the upper lid sulcus, ptosis, enophthalmos.
- Conjunctival hyperemia: mild redness, usually settles within weeks.
- Cystoid macular edema: rare, more concerning in pseudophakic eyes with disrupted posterior capsule.
- Caution in active uveitis or recent intraocular surgery; relative contraindication in pregnancy (theoretical concern about uterine prostaglandin effects).
Beta-Blockers
- Bradycardia, hypotension, syncope: systemic absorption through nasolacrimal drainage can produce clinically significant cardiac effects.
- Bronchospasm: non-selective beta-blockers (timolol) are contraindicated in asthma and severe COPD.
- Masking of hypoglycemia in diabetic patients.
- Depression, fatigue, decreased exercise tolerance.
- Avoid in second- or third-degree heart block, sinus bradycardia, decompensated heart failure.
- Punctal occlusion after instillation reduces systemic absorption substantially.
Alpha-2 Agonists
- Allergic conjunctivitis / follicular conjunctivitis: the most common reason brimonidine is discontinued, often appearing months into therapy.
- Dry mouth, fatigue, drowsiness from systemic absorption.
- CNS depression in infants: brimonidine is contraindicated in children under 2 due to risk of apnea and bradycardia, and used cautiously in older children.
- Avoid concurrent use with monoamine oxidase inhibitors (MAOIs).
Topical CAIs
- Stinging, burning on instillation, especially with dorzolamide (low pH).
- Bitter taste from drainage to the nasopharynx.
- Sulfa allergy: both dorzolamide and brinzolamide are sulfonamide derivatives. Documented severe sulfa hypersensitivity is a relative contraindication; mild sulfa intolerance is generally not.
- Corneal edema in patients with compromised endothelial function (Fuchs dystrophy, low cell counts).
Rho Kinase Inhibitors
- Conjunctival hyperemia: the most common side effect, often striking visually.
- Conjunctival hemorrhage: small subconjunctival bleeds, cosmetic only.
- Cornea verticillata: whorl-pattern epithelial deposits, asymptomatic, reversible.
- Instillation-site discomfort.
Cholinergic Agonists
- Miosis: small pupil, decreased night vision, brow ache from ciliary spasm.
- Increased risk of retinal detachment in high myopes due to traction from ciliary contraction.
- Avoid in patients with pupillary block angle closure where the lens is the obstructing element.
Tech Role in Administration and Patient Education
The technician carries most of the practical responsibility for medication management around the visit. The IJCAHPO Criteria of Knowledge for the COA call out medication history, drop instillation, and patient education as core technician duties.
Medication History at Check-In
- Reconcile every glaucoma drop currently used: name, strength, eye, frequency, time of last dose. A patient who took their morning timolol two hours before a planned IOP measurement will read artificially low.
- Ask specifically about adherence: "How many days in the last week did you miss a dose?" Open phrasing produces more honest answers than yes/no.
- Capture the bottle cap color when patients identify drops by appearance. Yellow caps for timolol 0.5 percent, teal for latanoprost, purple for brimonidine, orange for dorzolamide, and so on are well-recognized industry conventions.
- Document any side effects the patient has noticed: red eye, lash changes, taste in throat, fatigue, racing or slow pulse, breathing changes.
Drop Instillation Technique
Many patients do not instill drops well. Watching the patient demonstrate technique, then teaching the corrected method, is one of the highest-value things a technician can do. The standard sequence:
- Wash hands.
- Remove the cap, do not touch the dropper tip to anything.
- Tilt the head back or lie down.
- Pull the lower lid down to form a small pouch.
- Look up, place one drop in the pouch (not on the cornea), do not blink hard.
- Close the eye gently for 1-2 minutes and apply punctal occlusion with a finger pressed against the inner canthus to block nasolacrimal drainage.
- Wait 5 minutes between different drops to prevent washout.
- Wipe excess from the lid; replace the cap immediately.
Punctal occlusion alone reduces systemic absorption by a substantial fraction and is the single most useful change a tech can teach to reduce side effects from beta-blockers and alpha agonists.
Adherence Counseling
- Anchor doses to existing routines: bedtime PGAs to brushing teeth, twice-daily drops to morning coffee and dinner.
- Suggest a dosing app or pill organizer adapted for drops when the regimen has more than one bottle.
- Discuss cost: generic latanoprost and timolol are inexpensive; ask if cost is a reason for missed doses, since many patients will not volunteer this.
- Refill timing: a 2.5 mL bottle of once-daily PGA lasts roughly one month per eye. Patients who refill every three months are missing many doses or not using both eyes.
Side Effect Recognition
Flag for the doctor before the exam:
- New shortness of breath or wheeze in a patient on timolol (possible bronchospasm).
- Pulse under 50 in a patient on timolol (possible bradycardia).
- New, persistent red eye in a patient on brimonidine (possible follicular conjunctivitis).
- New ptosis or sunken-eye appearance in a patient on PGA (possible PAP).
- Patient reports stopping a drop on their own. Adherence and possible side effect both need attention.
Exam Tips
- Match drug to mechanism. ABO-NCLE and IJCAHPO items frequently give a class and ask which IOP pathway it acts on, or vice versa. Memorize: PGA and ROCK inhibitor and pilocarpine increase outflow; beta-blocker and CAI decrease production; alpha agonist does both modestly.
- Know the cap colors. COA-level questions often describe a bottle by cap color and ask the class. Yellow = timolol 0.5, teal = latanoprost, purple = brimonidine, orange = dorzolamide, dark green = pilocarpine, red = mydriatic (not glaucoma).
- Know the contraindications cold. Asthma plus timolol, infant plus brimonidine, severe sulfa allergy plus dorzolamide, pseudophakia with capsule rupture plus PGA: all classic test items.
- Punctal occlusion is the single most-tested tech intervention for reducing systemic absorption of glaucoma drops. It comes up on COA, COT, and ABO-NCLE pharmacology items.
- 5-minute spacing between different drops is the standard answer for preventing washout. If a question gives 1 or 2 minutes, that is a distractor.
- Generic vs. brand naming. Test items use generic names primarily but expect you to recognize common brand names. Latanoprost = Xalatan, timolol = Timoptic, brimonidine = Alphagan, dorzolamide = Trusopt, netarsudil = Rhopressa.
- PAP and lash changes are uniquely PGA. If a question describes a sunken upper lid or asymmetric long lashes, the answer is a prostaglandin analog.
- The American Academy of Ophthalmology Preferred Practice Pattern for Primary Open-Angle Glaucoma is the authoritative reference cited by IJCAHPO and ABO-NCLE for current first-line recommendations. Browse aao.org for the current edition.
Glaucoma medications are the most prescribed topical class in eye care, and the technician's ability to manage the medication list, instill correctly, teach correctly, and flag side effects directly affects whether the patient keeps their vision. Master this content and you will both pass the exam and contribute meaningfully on day one of clinic work.