The Danger of Overnight Contact Lenses - Orthokeratology-related Infectious Keratitis

PURPOSE: To present infectious keratitis associated with overnight orthokeratology lenses.

METHODS: This investigator-initiated, dual-centre, retrospective study reviewed patients with orthokeratology-associated infectious keratitis between 2021 and 2024.

RESULTS: We identified seven cases of infectious keratitis in orthokeratology lens wearers. The first was an 18-year-old female with bilateral severe keratitis. Corneal scrapings revealed Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus caprae/capitis, Cutibacterium acnes in the right eye, Staphylococcus aureus in the left, and Acinetobacter baumannii complex on both lenses. Despite intensive inpatient treatment, she discontinued care prematurely. The second was an 18-year-old female with unilateral Acanthamoeba keratitis confirmed by PCR and in vivo confocal microscopy. The anti-amoebic treatment resulted in clinical improvement. The third, a 20-year-old female, showed unilateral infectious keratitis without pathogens, improving under empirical antibiotics. The fourth, a 20-year-old male, presented with unilateral peripheral corneal infiltrates, neovascularisation, and corneal ulceration, improving without corneal scrapings. The fifth, a 34-year-old male, had severe unilateral keratitis with corneal ulceration and hypopyon. Corneal scrapings revealed Streptococcus dysgalacticae by culture and HSV-1 by PCR, which responded to intensive antiviral and antibiotic treatment. The sixth, a 34-year-old male, initially diagnosed with herpetic keratitis, was later PCR-confirmed for Acanthamoeba and required penetrating keratoplasty after prolonged anti-amoebic therapy. The seventh, a 17-year-old female, had PCR-confirmed Acanthamoeba keratitis and recovered to a corrected visual acuity of 1.2 after six months of anti-amoebic treatment.

DISCUSSION: Overnight orthokeratology lens use can be associated with severe, sight-threatening infectious keratitis of various microbial origins. Enhanced patient education and strict lens hygiene practices are critical to reducing such complications.