Management of Contact Lens‑Associated Bacterial Keratitis

Initial Assessment and Risk Stratification

Central or pupillary‑region ulcer involvement predicts poorer visual outcomes and warrants aggressive therapy. 1
Deep stromal infiltration or infiltrates > 2 mm with extensive suppuration require fortified antibiotic therapy. 1
Presence of a hypopyon signifies severe infection and mandates fortified antibiotics. 1

Topical fluoroquinolone monotherapy (ciprofloxacin 0.3 %, levofloxacin 1.5 % or moxifloxacin) is as effective as fortified combinations and should be first‑line. 1
Ciprofloxacin 0.3 % is FDA‑approved and provides the highest sensitivity against Pseudomonas aeruginosa, the pathogen in ~80 % of contact‑lens keratitis cases. 1
Levofloxacin 1.5 % is an FDA‑approved alternative fluoroquinolone. 1
Initial dosing: one drop every hour while awake, then taper according to clinical response. 1

Fortified antibiotic combination therapy is mandatory for these presentations. 1
Vancomycin 25–50 mg/mL + Ceftazidime 50 mg/mL achieves ~95 % pathogen sensitivity. 1
Vancomycin 25–50 mg/mL + Tobramycin 14 mg/mL provides broad gram‑positive and gram‑negative coverage, including Pseudomonas. 1
Loading dose: one drop every 5–15 minutes for the first hour. 1
Maintenance dose: one drop every hour around the clock initially. 1
Fortified preparations should be refrigerated and shaken well before each instillation. 3

Higher minimum inhibitory concentrations (MICs) of the chosen antibiotic are associated with slower re‑epithelialization and greater loss of visual acuity at 3 months. 1

Cycloplegic agents (e.g., cyclopentolate, homatropine) are recommended to reduce pain from anterior‑segment inflammation and to prevent synechiae formation. 1
Patching or bandage contact lenses should be avoided when epithelial defects are present, as they increase the risk of bacterial keratitis. 1

Obtain corneal scrapings for culture before initiating therapy, especially in severe cases. 1
A clinical response should be evident within 48–72 hours; lack of improvement mandates culture‑directed therapy adjustment. 1
Follow‑up daily for severe cases initially, then adjust frequency based on clinical improvement. 1

Ocular ointments should not be used as primary therapy because they lack adequate corneal penetration; they may be reserved for bedtime use in mild cases. 1
Do not delay fortified antibiotics for large or central ulcers; fluoroquinolone monotherapy is insufficient for severe disease. 1
Do not overlook a history of water exposure (swimming, showering, hot‑tub use with lenses) because it raises the risk of Acanthamoeba infection, which requires a different therapeutic approach. 3

Subconjunctival antibiotic injection can be considered if patient adherence is questionable or fortified antibiotics are delayed. 1
Systemic antibiotics are reserved for cases with scleral extension, intra‑ocular involvement, or systemic infection. 1