Pseudomonas aeruginosa is one of the important pathogens causing bacterial keratitis with ulceration. In this study, we evaluated a case of non-hospital-acquired P. aeruginosa keratitis in a 7-month-old infant and its treatment process. The patient who had no known chronic disease was brought in with complaints of watering and redness in the left eye. The complaint of the eye problems started 1 month ago after the patient swam in a farm pool. Keratitis was diagnosed according to an ophthalmologic examination in our clinic. Left corneal scraping cultures were taken for the identification of the pathogen. Moxifloxacin eye drops and ganciclovir gel were prescribed for 10 days. The corneal haze disappeared after the treatment. Reasons for delay in diagnosis and treatment were evaluated in our case. We also compared the keratitis between adults and infants. P. aeruginosa keratitis should be considered in the differential diagnosis, taking into account the presence of resistance to treatment, visual disturbances, lens usage, nasolacrimal duct obstruction, trauma, and bad hygiene. Congenital nasolacrimal duct obstruction is an important risk factor for infants. Vision loss, which may happen in adults, cannot be clearly communicated by infants due to their limited communication abilities. P. aeruginosa should be considered the pathogen causing keratitis in infant patients, particularly when the diagnosed characteristics align with our case.