1. Antibiotic Susceptibilities in Patients With Contact Lens Associated Microbial Keratitis Jimmy Lim 1, Muhammad A. Ismail 2 Eileen Sim 2, Timothy Barkham 3, Wee Jin Heng 1 1 Department of Ophthalmology, Tan Tock Seng Hospital (TTSH), 2 Yong Loo Lin School of Medicine, NUS. 3 Department of Microbiology, TTSH. Singapore. The authors have no financial interest in the subject matter of this e-poster

2. Purpose Our study aims to characterize the symptoms and habits of patients presenting with contact lens keratitis. To analyze the microbial cultures and antibiotic susceptibilities of the isolates from corneal scrapings of these patients.

3. Method We retrospectively analyzed 127 patients with contact lens related keratitis, who were managed at National Healthcare Group Eye Institute, Tan Tock Seng Hospital (NHGEI, TTSH), Singapore. Between January 2007 and September 2009.

4. Results The average age of our patients is 25.5 years. There were 58 males (46%) and 69 females (54%). The most common contact lens used was the soft, monthly disposable lens (80%).

5. Results The median duration of symptoms before presentation is 2 days. The most common symptoms were pain (83%), red eye (71%), eye discharge (35%) and blurring of vision (30%).

6. # * *BOV – Blurring of Vision # FB – Foreign Body Sensation

7. Results The average hours of daily contact lens wear was 12.9 hours. 30% of the patients swam or took baths while wearing their lenses, and 27% slept or took naps while wearing their contact lenses.

8. Microbial Cultures An etiological microbial agent was found in 70% of the cases. The most common organisms in descending order were; ◦ Pseudomonas aeruginosa ◦ Coagulase-negative Staphylococcus ◦ Serratia marcescens Together accounting for 63% of all isolates.

9. *4 patients had polybacterial keratitis, while 1 patient had a recurrent infection.

10. Antibiotic Susceptibilities

11. Conclusion Knowledge of the symptoms and habits of patients with contact lens related keratitis is useful in their diagnosis and management. Patient education of at-risk habits may be helpful in preventing contact lens keratitis.

12. Conclusion Pseudomonas aeruginosa was the most frequent isolate. The 3 most common organisms were susceptible to Ciprofloxacin. Ciprofloxacin would be an effective choice for empirical antibiotic treatment of contact lens related microbial keratitis in general practice where fortified gentamicin is unavailable.