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A 54-year-old contact lens wearer with a red painful eye and a corneal infiltrate

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A 54-year-old contact lens wearer with a red painful eye and a corneal infiltrate

A 54-year-old woman who wears monthly soft contact lenses on an extended-wear basis presents on a Saturday morning with a painful red left eye for 18 hours. She has been swimming in a hotel pool while wearing her lenses and admits to sleeping in them twice this week. Vision is 6/12 OS versus 6/6 OD. There is diffuse conjunctival injection, a 1.5 mm focal white infiltrate in the peripheral cornea at 4 o'clock with overlying epithelial defect, and mild anterior chamber reaction. The fellow eye is quiet. You are a sole practitioner with no slit-lamp photography and the nearest ophthalmology service is 90 minutes away; the on-call ophthalmologist will only accept direct calls for emergencies.

1. Differentiate microbial keratitis from a contact-lens-related red eye. What features raise your suspicion for a sight-threatening process here?

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Differential diagnosis of the red, painful contact lens eye:

  1. Microbial keratitis - focal infiltrate, overlying epithelial defect, pain, reduced vision, anterior chamber reaction, risk factors (extended wear, swimming in lenses).
  2. Contact lens peripheral ulcer (CLPU) - small, peripheral, round infiltrate with an epithelial defect, often asymptomatic or mildly symptomatic, typically in daily-wear users; usually responds to lens cessation.
  3. Corneal abrasion - linear or geographic defect, no infiltrate.
  4. Acanthamoeba keratitis - severe pain out of proportion, ring infiltrate, history of swimming or tap water; often develops more slowly.
  5. Herpetic keratitis - dendritic defect, reduced corneal sensation.

Features raising suspicion of a sight-threatening process:

  • Focal white infiltrate with overlying epithelial defect - the hallmark of microbial keratitis.
  • Anterior chamber reaction - indicates intraocular inflammation beyond the epithelium.
  • Reduced vision to 6/12 - functional impact.
  • Risk factors: extended wear (the strongest risk factor for microbial keratitis), swimming in lenses (Pseudomonas and Acanthamoeba risk).
  • Pain and 18-hour course - acute bacterial keratitis is the leading concern.

Key exam point: a CLPU is a diagnosis of exclusion in a low-risk patient. This patient has multiple high-risk features, so you must manage as presumed microbial keratitis until proven otherwise.

2. What is your immediate management, including what you can and cannot do in a primary care setting, and when do you escalate?

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Immediate management:

  1. Cease lens wear in both eyes and discard the current lenses and case.
  2. Do not patch - patching a potentially infected cornea is contraindicated.
  3. Do not prescribe topical steroids.
  4. Start intensive topical antibiotic - a fluoroquinolone (e.g. ofloxacin or ciprofloxacin) hourly, including overnight for the first 24–48 hours, is standard first-line for presumed bacterial keratitis in primary care where culture is unavailable. If you do not stock it, arrange urgent supply.
  5. Analgesia and clear written instructions.
  6. Same-day ophthalmology contact - call the on-call service. A 1.5 mm peripheral infiltrate with AC reaction and reduced vision in a high-risk lens wearer meets the threshold for specialist review. The 90-minute distance is a logistics problem, not a reason to delay the call.
  7. Document the size, location, depth, epithelial defect dimensions, AC reaction, and acuity so the receiving clinician can track change.

What you cannot do here:

  • You cannot culture in a primary practice without microbiology access, so you must treat empirically and let the hospital culture if they choose.
  • You cannot safely observe this without specialist input given the AC reaction.

Escalation triggers:

  • Infiltrate enlarging, deepening, or approaching the visual axis.
  • Worsening vision, increasing AC reaction or hypopyon.
  • Severe pain out of proportion (consider Acanthamoeba).
  • No improvement in 24–48 hours.

Review: see the patient the next day if the hospital does not take over; otherwise confirm handover.

3. What do you tell the patient about prevention, and what does this case teach about extended wear?

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Prevention counselling - be specific and non-judgemental:

  • Never sleep in lenses. Extended wear increases the risk of microbial keratitis substantially compared with daily wear; this is the single most important message.
  • Never swim or shower in lenses. Water exposure risks Pseudomonas and Acanthamoeba. If swimming is unavoidable, use daily disposable lenses with tight-fitting goggles and discard afterwards.
  • Hand hygiene before insertion and removal, with hand drying.
  • Replace lenses and cases on schedule; never top up solution or use tap water.
  • Remove lenses at the first sign of redness, pain, or reduced vision and seek care.
  • Have a back-up pair of spectacles.

What this case teaches about extended wear:

  • Extended wear is a legitimate modality but carries a higher risk of keratitis than daily wear; patients must be selected, consented, and reviewed carefully.
  • Swimming in lenses while on extended wear compounds risk.
  • The Saturday presentation is a reminder that contact lens complications do not respect clinic hours - patients need an after-hours plan.

Documentation: record the counselling, the lens type and wearing schedule, and that the patient was advised to stop lens wear until cleared. Advise a follow-up refraction and refit only after full resolution and specialist clearance.