Painful Red Eye in a Extended-Wear Silicone Hydrogel Patient

A focal infiltrate with an overlying epithelial defect in an extended-wear patient is presumed microbial keratitis until proven otherwise - that is the frame for everything else.

• Bacterial (especially Pseudomonas) keratitis - top of list. Supported by: acute onset, pain, defect overlying the infiltrate, anterior chamber reaction, extended wear, old lenses, water exposure. Pseudomonas can progress rapidly and may show a ring or melt; a worsening clinical course within 24 h supports it.
• Acanthamoeba keratitis - must not be missed. Supported by: tap-water case rinsing, lake swimming, pain out of proportion to signs, and later a ring infiltrate or perineural involvement. Early cases look unremarkable, so the exposure history is the main clue.
• Contact lens–induced infiltrative keratitis (IK). Usually smaller, multiple, peripheral, with an intact epithelium and less pain; steroid-responsive. Downgrade here because the epithelium is broken and symptoms are marked.
• CLARE. Diffuse punctate staining, no focal infiltrate - doesn't fit.
• Fungal keratitis. Indolent, feathery margins, history of organic trauma; unlikely at two days but keep in mind if the course is atypical.
• Simple abrasion or foreign body. Doesn't explain a 1.4 mm stromal infiltrate.

The deciding information: scrape/culture results, the size and character of the defect, pain trajectory over 24 h, and any ring or satellite lesions.

Do:

• Remove and discard the lens and the case; do not culture the lens instead of the cornea.
• Corneal scrape for smears and culture (bacterial and, given the water exposure, acanthamoeba) before starting therapy - but never delay treatment to obtain it if the eye is threatened.
• Start intensive topical antibiotic: a fluoroquinolone such as moxifloxacin hourly, or fortified cefazolin/tobramycin, day and night initially.
• Review at 24 h, then daily until the epithelium heals and the infiltrate is consolidating. Refer or co-manage with ophthalmology if the infiltrate is central, large, or worsening.
• Cycloplegic for comfort if needed; preservative-free lubricants; analgesia as appropriate.

Do not:

• Do not patch an eye with a suspected infectious infiltrate.
• Do not use a steroid alone or as first-line - steroids without effective antimicrobial cover can let a bacterial or acanthamoeba infection escape.
• Do not let him resume lens wear of any kind until the eye is fully resolved and you have refitted him.
• Do not reassure on the basis of "it's probably just an infiltrate" - the diagnosis is made by the response to treatment over 24 h.

Document the presentation, the advice, the water exposures, and the follow-up plan.

This event was almost entirely modifiable, so the refit is a risk-reduction exercise, not a lens swap:

• Move him off extended wear. Overnight wear is the single largest driver of microbial keratitis; daily wear reduces the risk substantially and this must be non-negotiable, not a preference. Offer daily disposable silicone hydrogel if he wants minimal handling - it removes the case and the solution from the equation.
• Fix the replacement interval. A 2-month-old monthly lens on nightly wear is a compliance failure that compounded everything else.
• Eliminate water contact. No tap-water case rinsing (rub and rinse with solution, air-dry face down, replace the case monthly), no showering in lenses, no swimming in lenses; if he insists on swimming, daily disposables with tight-fitting goggles and lens removal immediately afterwards.
• Red-flag script. Pain, light sensitivity, or blurred vision = lens out, call the same day, do not sleep on it.
• Document and communicate the refit rationale and the residual scar to the patient in writing, and note that the scar may cause mild irregular astigmatism requiring a toric or a refined fit.

Reinforce that the rules are the treatment, not paperwork: patients who understand why overnight wear and water are dangerous adhere better than those simply told 'don't'.