Ocular Therapeutics & Prescribing Clinical Manual
Complete Canadian drug monographs, dosage protocols, contraindications, steroid tapering matrices, emergency algorithms, and board-level case simulators.
00. TPAO Exam Blueprint & Core Competencies
OVERVIEWThe Therapeutics Prescribing Assessment for Optometry (TPAO) is a 98-question written multiple-choice examination administered by the Touchstone Institute. It evaluates your competence to safely prescribe, monitor, and adjust drug therapies currently authorized for optometrists in Canada.
Selecting 1st-line drug therapy vs. alternatives based on clinical presentation.
Mechanisms, adverse effects, systemic contraindications, and drug interactions.
Follow-up intervals, treatment response, steroid tapering, and emergency triage.
01. Glaucoma & Hypotensive Drug Classes
CH 01Latanoprost 0.005%, Travoprost 0.004%, Bimatoprost 0.01%/0.03%
Selective FP prostanoid receptor agonist that increases uveoscleral outflow (unconventional pathway).
1 drop QHS (at bedtime).
Morning dosing is less effective due to diurnal receptor down-regulation.
Iris color darkening (permanent), eyelash hypertrichosis, periorbital fat atrophy (PAP), CME. Avoid in active uveitis & history of epithelial HSV.
Timolol Maleate 0.25% / 0.5% (Timoptic, Timoptic-XE)
Non-selective $\beta_1$ and $\beta_2$ adrenergic antagonist that decreases aqueous humor production by the ciliary epithelium.
1 drop QAM (morning) or BID.
Little nighttime pressure efficacy because aqueous production naturally drops during sleep.
Asthma, severe COPD, sinus bradycardia (<50 bpm), 2nd/3rd degree heart block, decompensated CHF.
Brimonidine Tartrate 0.1% / 0.15% (Alphagan P)
Dual action: Decreases aqueous production AND increases uveoscleral outflow.
1 drop TID (monotherapy) or BID (adjunct).
CONTRAINDICATED in children under 2 years / <20 kg (crosses blood-brain barrier causing CNS depression, bradycardia, hypotension, apnea).
Dorzolamide 2% (Trusopt), Brinzolamide 1% (Azopt), Acetazolamide (Diamox)
Inhibits carbonic anhydrase II in non-pigmented ciliary epithelium, decreasing bicarbonate production and aqueous secretion.
Topical: TID (mono) or BID (adjunct).
Oral Diamox: 250mg tab or 500mg sequel.
Sulfa allergy, severe renal disease (GFR <30), hepatic impairment, hypokalemia, aplastic anemia (oral).
02. Anti-Infectives & Microbial Keratitis
CH 02Step-by-Step Microbial Keratitis Management Algorithm
⢠Drug: Moxifloxacin 0.5% (Vigamox) or Besifloxacin 0.6% (Besivance) 1 drop every 1 to 2 hours while awake.
⢠Adjunct: Cyclopentolate 1% BID (relieves ciliary spasm pain).
⢠Follow-up: Mandatory in 24 hours.
⢠Loading Regimen: 1 drop every 15 minutes for the first 2 hours, then 1 drop every 1 hour around the clock (including through the night).
⢠Choice: Fortified Tobramycin (15 mg/mL) alternating with Fortified Cefazolin (50 mg/mL) OR 4th Gen Fluoroquinolone.
⢠Golden Rule: NO STEROIDS until re-epithelialization is established and organism is controlled (minimum 48â72h).
03. Topical Corticosteroids & Step-Down Tapering
CH 03Corticosteroids are essential for treating sterile inflammatory ocular conditions (Anterior Uveitis, Episcleritis, Stromal Keratitis). Sudden cessation causes rebound inflammation. Always taper gradually based on anterior chamber cell resolution.
⢠Ketone formulation, high penetration.
⢠Shake suspension well before instillation.
⢠Uveitis Regimen: Q1h or Q2h initially until AC cells drop to <1+, then taper weekly: QID $\rightarrow$ TID $\rightarrow$ BID $\rightarrow$ Daily $\rightarrow$ Stop.
⢠Ester-based "soft steroid".
⢠Rapidly converted into inactive metabolites by esterases in the anterior chamber.
⢠Clinical Value: Lowest risk of intraocular pressure elevation (ideal for steroid responders).
04. Topical NSAIDs & Anti-Allergy Formulations
CH 04Ketorolac 0.4%/0.5% (Acular), Nepafenac 0.1%/0.3% (Nevanac/Ilevro), Bromfenac 0.07% (Prolensa)
Inhibits cyclooxygenase (COX-1 & COX-2) preventing prostaglandin synthesis.
⢠Primary Indications: Post-cataract surgery inflammation, prevention/treatment of Cystoid Macular Edema (CME), refractive surgery pain.
â ïž Warning: Risk of corneal melting in compromised/neurotrophic corneas.
Olopatadine 0.1%/0.2%/0.7% (Patanol/Pataday/Pazeo), Alcaftadine 0.25% (Lastacaft), Ketotifen 0.025% (Zaditor)
Dual action: Histamine $H_1$ receptor antagonist + Mast cell stabilizer.
⢠Primary Indication: Allergic conjunctivitis itching and redness.
⢠Dosing: Olopatadine 0.2% is 1 drop once daily (QD); Olopatadine 0.1% is 1 drop BID.
05. Ocular Antivirals: HSV & HZO Protocols
CH 05| Condition | Clinical Hallmark | First-Line Treatment | Contraindications & Cautions |
|---|---|---|---|
| HSV Epithelial Keratitis | True branching dendrites with terminal end-bulbs, reduced corneal sensation. |
Topical: Ganciclovir 0.15% gel (Zirgan) 5x/day until healed, then TID x 7d. Oral: Valacyclovir 500mg TID x 7â10d (or Acyclovir 400mg 5x/day). |
NO topical steroids during epithelial replication phase (causes geographic ulcers). |
| Herpes Zoster Ophthalmicus (HZO) | Dermatomal CN V1 vesicular rash respecting midline, Hutchinson's sign on nasal tip. | Oral Valacyclovir: 1000mg TID x 7 days (or Acyclovir 800mg 5x/day x 7d). Must start within 72h. | Dose reduction required in renal impairment. Monitor for neuro-ophthalmic complications. |
06. Oral Systemic Antibiotics in Optometry
CH 06Cephalexin (Keflex) 500mg BID/QID or Amoxicillin-Clavulanate (Augmentin) 875mg BID
Gram-positive coverage targeting Staphylococcus aureus and Streptococcus pneumoniae.
⢠Dosing duration: 7 to 10 days.
⢠In penicillin/cephalosporin allergy: Doxycycline 100mg BID or Trimethoprim-Sulfamethoxazole (Bactrim DS) 1 tab BID.
Doxycycline 50mgâ100mg Daily / BID
Sub-antimicrobial dose provides matrix metalloproteinase (MMP-9) inhibition and anti-inflammatory action.
â ïž Contraindicated in pregnancy, nursing mothers, and children <8 years (causes tooth discoloration & bone growth stunting).
07. Acute Ocular Emergencies Protocols
CH 07⢠Timolol 0.5% (1 drop)
⢠Apraclonidine 1% (1 drop)
⢠Dorzolamide 2% (1 drop)
⢠Oral Acetazolamide (Diamox) 500mg STAT (two 250mg tabs)
Verify no sulfa allergy.
⢠Recheck IOP in 30â45 min.
Instill Pilocarpine 1â2% once IOP drops <40 mmHg (ischemic sphincter will not constrict at >45 mmHg).
⢠Immediate referral for bilateral Laser Peripheral Iridotomy (LPI).
08. Canadian Prescription Writing Templates
CH 08Rx: Latanoprost 0.005% ophthalmic solution Sig: Instill 1 drop into both eyes (OU) once daily at bedtime (QHS). Mitte: 1 x 2.5 mL bottle Refills: 3 (three)
Rx: Prednisolone Acetate 1% suspension (Pred Forte) Sig: Shake well. Instill 1 drop into right eye (OD) every 1 hour while awake for 3 days, then every 2 hours until follow-up in 4 days. Mitte: 1 x 10 mL bottle Refills: 0 (zero)
09. Interactive Steroid Taper Generator
CALCULATOR10. TPAO Practice Case Simulator
EXAM MODEA 67-year-old male with newly diagnosed Primary Open-Angle Glaucoma has a medical history of moderate COPD and sinus bradycardia (HR 50 bpm). Which of the following is the MOST appropriate first-line pressure-lowering agent?
Non-selective beta-blockers like Timolol (and combination drops like Cosopt) are absolutely contraindicated in patients with asthma/COPD and bradycardia. Latanoprost (PGA) is first-line with no pulmonary or cardiac contraindications.
A 24-year-old soft contact lens wearer presents with a 2.5mm central bacterial corneal ulcer with 2+ anterior chamber cells. What is the MOST appropriate initial topical loading regimen?
Large or central bacterial keratitis in contact lens wearers requires aggressive loading doses of a 4th-generation fluoroquinolone (Moxifloxacin/Besifloxacin) around the clock. Topical steroids are strictly contraindicated in the acute infectious stage.