To report a case of Serratia marcescens keratitis presenting as radial keratoneuritis.

A 15-year-old female who wore cosmetic and orthokeratology contact lenses but performed inadequate lens care visited our clinic with severe pain and visual disturbance in her left eye. On slit lamp examination, central corneal epithelial defect and stromal infiltration with radial keratoneuritis were observed. Based on clinical findings and past history, Acanthamoeba keratitis was highly suspected. The patient was treated with topical chlorhexidine 0.02% (Sigma-Aldrich Co., MO, USA) and moxifloxacin 0.5% (Vigamox®, Alcon, TX, USA) per hour with 200 mg of oral itraconazol (Sporaone®, LG, Seoul, Korea) once a day. Symptoms and corneal lesions did not improve after three days. After Serratia marsenscens was isolated from her contact lenses and solution, topical chlorhexidine 0.02% was discontinued, and intravenous ceftazidime (Tazime®, Hanmi, Seoul, Korea) and fortified ceftazidime (50 mg/mL) eye drop was added. The corneal lesion dramatically improved, and after six months of follow-up, best-corrected visual acuity was 20/20 in the affected eye.

Radial keratoneuritis can present not only in Acanthamoeba keratitis, but also in Serratia marsenscens keratitis. Confirmation of the isolated organism is useful when treating radial keratoneuritis.