Keratitis vs conjunctivitis
Structured for Australian optometry practice.
Clinical decision support only
OptoGuide™ supports professional judgement and does not diagnose or replace clinician responsibility.
Quick answer
- Keratitis is usually more painful, more photophobic, and more vision-threatening than uncomplicated conjunctivitis.
- Contact lens wear, focal staining, infiltrate, and reduced vision should shift the working diagnosis toward keratitis.
- Conjunctivitis more often presents with diffuse injection and discharge without significant pain or corneal staining.
- When the cornea is involved, manage as a safety issue first and escalate early.
Common causes
- Bacterial, viral, or allergic conjunctivitis.
- Contact lens-related keratitis or microbial keratitis.
- Herpetic keratitis.
- Surface inflammation with secondary conjunctival redness.
Red flags (must not miss)
- Contact lens wear with pain or focal corneal staining.
- Reduced visual acuity, marked photophobia, or corneal opacity.
- Unilateral severe symptoms not matching simple conjunctivitis.
- Dendritic staining pattern or stromal haze.
Use OptoGuide™ to guide this decision during consult.
What to check
- Visual acuity and pain severity.
- Discharge pattern and laterality.
- Fluorescein staining for epithelial defect or infiltrate.
- Corneal clarity, anterior chamber reaction, and photophobia.
- Contact lens history and overnight wear exposure.
When to refer
- Same day for suspected microbial or herpetic keratitis.
- Urgent review when corneal involvement is present and the diagnosis is uncertain.
- Routine care only when the picture is consistent with uncomplicated conjunctivitis and vision is unaffected.
Initial management
- Do not treat a painful red contact lens eye as simple conjunctivitis.
- Separate conjunctival disease from corneal disease early in the exam.
- Document staining pattern, infiltrate presence, acuity, and lens history before escalation.
Clinical basis
This guidance reflects standard optometric clinical reasoning based on:
- Australian optometry clinical practice patterns
- Australian medicines regulation and PBS prescribing context
- Common ophthalmology referral standards
- Evidence-based clinical training and practice
Use OptoGuide™ during consult for structured clinical guidance.