Contact Lens‑Related Keratitis

Overview

Keratitis is inflammation of the cornea, the clear front surface of the eye. When it occurs in people who wear contact lenses, it is often called contact lens‑related keratitis. The condition can be caused by bacteria, fungi, parasites (e.g., Acanthamoeba), or by non‑infectious irritation from lens wear. Prompt recognition and treatment are essential because untreated keratitis can lead to corneal scarring, vision loss, or even loss of the eye.

Most cases are bacterial (e.g., Staphylococcus aureus, Pseudomonas aeruginosa) or caused by the protozoan Acanthamoeba, especially in users who expose lenses to water or fail to follow proper hygiene.^[1][2]

Symptoms Checklist

• Redness of the eye
• Eye pain or a gritty sensation
• Blurred or decreased vision
• Excessive tearing or discharge (purulent or watery)
• Photophobia (sensitivity to light)
• Swelling of the eyelids
• Feeling that something is “stuck” under the eyelid

Risk Factors

• Extended wear of soft contact lenses (overnight or >6 days continuously)
• Poor lens hygiene – e.g., re‑using solution, not cleaning case, or using tap water
• Wearing lenses while swimming, showering, or in hot tubs
• Using expired or improperly stored lenses/solution
• Pre‑existing ocular surface disease (dry eye, blepharitis)
• Immunocompromised state (diabetes, HIV, systemic steroids)
• History of previous keratitis or corneal trauma

Diagnosis

Diagnosis is usually made by an eye‑care professional (optometrist or ophthalmologist) and includes:

1. Clinical examination – slit‑lamp biomicroscopy to assess corneal infiltrates, ulceration, or epithelial defects.
2. Fluorescein staining – a dye that highlights corneal abrasions or ulcers.
3. Microbiological cultures – swab or scrapings of the cornea sent for bacterial, fungal, or Acanthamoeba cultures when infection is suspected.
4. Confocal microscopy – high‑resolution imaging useful for detecting Acanthamoeba cysts.
5. Polymerase‑chain‑reaction (PCR) testing – increasingly used for rapid identification of viral or atypical bacterial pathogens.

In many cases, the clinician will start empiric therapy while awaiting culture results.^[3][4]

Treatment Options

Medical Treatments

• Topical antibiotics – fluoroquinolones (e.g., moxifloxacin) or fortified antibiotics (e.g., cefazolin + tobramycin) for bacterial keratitis.
• Topical antifungals – natamycin 5% for fungal keratitis.
• Anti‑Acanthamoeba therapy – combination of polyhexamethylene biguanide (PHMB) or chlorhexidine with propamidine isethionate; treatment may last weeks.
• Corticosteroid eye drops – used cautiously after the infection is under control to reduce inflammation and scarring.
• Systemic therapy – oral antifungals or antibiotics for severe or deep infections.

Home / Supportive Care

• Stop wearing contact lenses immediately; discard the current pair and case.
• Use preservative‑free artificial tears to keep the ocular surface moist.
• Apply cold compresses for comfort if there is swelling.
• Maintain strict hand hygiene before any eye‑related care.
• Follow the prescribed medication schedule exactly; do not skip doses.

Prevention

• Follow the “3‑6‑9” rule – replace soft lenses every 3 months (or as directed), replace rigid gas‑permeable lenses every 6 months, and replace disposable lenses every 9 days.
• Never expose lenses or lens solution to water (including tap, swimming pools, hot tubs).
• Clean and replace the lens case at least once a week; discard it after 3 months.
• Use only FDA‑approved multipurpose disinfecting solutions; never “top‑off” old solution.
• Wash hands with soap and dry them before handling lenses.
• Avoid sleeping in lenses unless they are specifically approved for extended wear.
• Schedule regular eye exams (at least annually) to monitor corneal health.

Living With Contact Lens‑Related Keratitis

Even after successful treatment, many patients wonder how to safely return to lens wear.

• Wait for clearance – your eye‑care provider will confirm that the cornea is fully healed before you resume lenses.
• Consider a new lens material – silicone‑hydrogel lenses have higher oxygen permeability and may reduce hypoxia‑related complications.
• Use daily disposable lenses – eliminates the need for cleaning solutions and case hygiene.
• Maintain a symptom diary – note any redness, discomfort, or visual changes and report them promptly.
• Protect your eyes – wear protective eyewear when doing activities that could expose your eyes to dust or chemicals.

When to Seek Emergency Care

If you experience any of the following, seek immediate ophthalmic or emergency department care:

• Sudden loss of vision or marked visual blur.
• Severe eye pain that does not improve with over‑the‑counter lubricants.
• Rapidly increasing redness or swelling.
• Large amount of pus or thick discharge.
• Sensitivity to light that worsens.
• History of recent eye trauma combined with contact lens wear.

Medical Disclaimer: This guide is for informational purposes only and does not substitute professional medical advice, diagnosis, or treatment. Always consult a qualified health‑care provider regarding any eye condition or before making changes to your eye‑care routine.