A 30-year-old soft contact lens wearer who sleeps in his lenses presents with a rapidly progressive central corneal ulcer with copious purulent discharge and marked anterior chamber reaction. Which organism is the most likely cause?
- A Staphylococcus epidermidis
- B Pseudomonas aeruginosa ✓
- C Streptococcus pneumoniae
- D Moraxella lacunata
Correct answer: B. Pseudomonas aeruginosa
Explanation
Pseudomonas aeruginosa is the classic pathogen of contact lens related bacterial keratitis, especially with overnight wear. It adheres to lens surfaces, produces proteases and elastase that cause rapid stromal melting, and can perforate within days. Streptococcus pneumoniae causes the classical central hypopyon ulcer of the non-lens-wearing population, while coagulase negative staphylococci cause indolent ulcers in contact lens wearers.
Reference: Parsons' Diseases of the Eye, 23rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.