On-Call Telephone Triage: Contact Lens Wearer with a Corneal Opacity
A 26-year-old graduate student who wears monthly silicone hydrogel lenses with occasional overnight use calls the on-call line at 1:40 a.m. She reports 2 days of a scratchy right eye that became acutely painful 6 hours ago, with photophobia, tearing, and a foreign-body sensation. She removed her lens 36 hours ago and has been using an expired bottle of artificial tears. Vision is blurry; she can read the 20/50 line on a phone app at arm's length. She describes a white spot on the cornea seen in the mirror, and the eye is 'completely red.' She has no ocular surgery or trauma, no history of cold sores, and takes no medications. She lives 2 hours from the nearest hospital with ophthalmology coverage and 20 minutes from your office. Her last eye examination was 3 years ago. She asks whether she can start the antibiotic drops her roommate has left over and be seen Monday.
1. State your differential and disposition. What do you tell her on the phone?
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Treat this as a corneal ulcer until proven otherwise. Red flags: contact lens wear including overnight use, pain out of proportion, photophobia, decreased vision, and a visible white corneal opacity. This is a same-day emergency, not a Monday appointment.
Differential, in order: bacterial keratitis (Pseudomonas is the classic overnight-wear organism), Acanthamoeba (ask about tap water, hot tubs, homemade saline), HSV epithelial keratitis (no cold sores, but ask about prior episodes), sterile contact-lens-related infiltrate, and retained foreign body.
Disposition: she is 20 minutes from your office and 2 hours from ophthalmology coverage. Arrange to see her within a few hours; if the opacity is central, larger than ~1–2 mm, or there is any hypopion or acuity worse than 20/60, escalate to the emergency department with ophthalmology that night.
Refuse the request for leftover drops. The drug may be wrong, expired, or inadequate; it obscures the lesion before it can be measured and creates false reassurance. Do not patch.
Phone instructions: remove lenses, bring lenses, case, and solution, stop all lens wear, preservative-free artificial tears only, no patching, go directly to the ED if pain or vision worsens.
2. She is seen at 7 a.m. with a 2 mm paracentral infiltrate and 1+ anterior chamber cells. Describe your examination and treatment.
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Slit lamp first, decisions second. With fluorescein, measure the infiltrate (size, distance from the visual axis, depth, overlying epithelial defect), grade cell and flare, check for hypopion, perform a Seidel test, evert the lids for foreign bodies, and examine the fellow eye.
Treat aggressively: moxifloxacin 0.5% (or fortified tobramycin/cefazolin if you prefer fortified agents for a 2 mm lesion). Loading dose every 5–15 minutes for the first hour, then every hour while awake. Scrape and culture before treatment for a lesion this size, and consider Acanthamoeba and fungal cultures if history suggests it. Cycloplege with cyclopentolate 1% for pain and synechiae prevention. No topical steroid until the infection is controlled and the epithelium is healing. No patching - it can worsen a bacterial ulcer.
Recheck at 24 hours, sooner if worse; monitor infiltrate size, epithelial defect, and anterior chamber reaction. If compliance is doubtful or the lesion enlarges, arrange fortified drops around the clock or hospitalization.
Document the reasoning for treating outpatient rather than admitting, since a 2 mm paracentral lesion with cells is at the aggressive end of office management.
3. What do you document about the phone call, and what prevention counseling and follow-up do you give?
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Document the call itself: time, who spoke to whom, symptoms reported, advice given (same-day evaluation, no leftover drops, no patching), and her response. Telephone advice is a frequent source of liability; a contemporaneous note that you recommended urgent care protects both of you.
Prevention counseling once the eye is quiet: overnight wear carries a markedly higher relative risk of microbial keratitis than daily wear; her 'occasional' overnight use is the highest-yield behavior to change. Reinforce hand washing and drying, no tap water or homemade saline, no swimming or showering in lenses, on-schedule lens and case replacement, and never using expired solutions. Discuss daily disposables as a lower-risk option for her schedule.
Set expectations at the first visit: even with appropriate treatment, a paracentral scar can permanently reduce best-corrected acuity, and irregular astigmatism may later require a rigid or scleral lens. Say this early so the stakes are clear.
Follow-up: daily until the epithelial defect is healing and the infiltrate is shrinking, then weekly until resolved; re-refract at 4–6 weeks. Refer for a corneal subspecialty opinion if the lesion fails to improve within 48–72 hours or if the visual axis is threatened.