To the Editor: Microbial keratitis associated with soft contact lens wear is a well recognised, not uncommon, clinical entity and a preventable cause of ocular morbidity.1,2

A 31-year-old woman who occasionally wore soft contact lenses presented to a general practitioner with a 2-day history of bilateral red eye associated with ocular discomfort, photophobia and purulent discharge. She was diagnosed with bilateral conjunctivitis, commenced on chloramphenicol drops and told to return in 5 days. Her symptoms initially improved, but then worsened. Seven days after symptom onset, she presented to hospital for assessment.

History revealed that she had worn soft monthly disposable contact lenses twice in the previous month to correct her mild myopia. On examination, the patient’s visual acuity was equivalent to being legally “blind”, being hand movement in the right eye and light perception in the left. On inspection, both eyes appeared grossly abnormal. The right eye had a large central corneal abscess and the left eye had a complete corneal abscess with 360° peripheral corneal thinning (Box, A) — a significant risk for globe perforation. The conjunctiva was markedly injected bilaterally.

Corneal scrapes, the contact lenses and the case containing turbid solution were sent for urgent gram stains and microbiological culture. The patient was admitted to hospital and received intensive topical treatment with gentamicin 0.9%, cephalothin 5% and tobramycin ointment. The corneal scrapes revealed Pseudomonas aeruginosa as the causative organism. The patient showed slow improvement with antibiotic therapy. Although the infection cleared, the residual corneal scarring resulted in permanent loss of corneal clarity and hence vision.

Four months after treatment was commenced, the patient’s visual acuity had improved to 6/24 in the right eye and 6/36 in the left (Box, B). An Australian review of outcomes after keratitis found that 52% of patients had a final visual acuity of worse than 6/12, the legal visual acuity for driving.3 In this patient, despite saving both eyes and the improvement in her vision, she still has significant functional impairment, being unable to work as a teacher or drive. Corneal transplantation is now her only option for potentially regaining the loss in her functional vision, with a minimum expected recovery time of 2 years.

GPs have a difficult job distinguishing between red eye requiring immediate referral and red eye that is not vision-threatening. All contact lens wearers who present with red eye need to be examined for yellow/white corneal infiltrates and, if present, or if the patient cannot be assessed adequately, immediate referral is mandatory. P. aeruginosa is the most common pathogen and one of the most aggressive organisms isolated in contact lens-related microbial keratitis.4 As it is invariably resistant to the bacteriostatic chloramphenicol, the appropriate empirical treatment is either fluoroquinolones or cephalosporins, which ideally should be commenced after corneal scrapes have been performed.5

Left eye at presentation and after 4 months of treatment

A: At presentation, there was marked conjunctival injection, 100% epithelial defect (stained with fluorescein [green]) and severe circumferential peripheral corneal thinning (arrow).

B: Four months after presentation, there was dense central scarring and peripheral corneal neovascularisation (arrow).