Etiology and Clinical Outcomes of Microbial Keratitis at a Tertiary Eye-Care Center in Northern Thailand
Napaporn Tananuvat MD*, Oranit Punyakhum MD*, Somsangaun Ausayakhun MD, MHSc*, Winai Chaidaroon MD*
Affiliation : * Department of Ophthalmology, Chiang Mai University, Chiang Mai, Thailand
Objective : To establish the predisposing factors, microbial profiles, demographics of patients and clinical outcomes of
microbial keratitis at a tertiary eye center in northern Thailand.
Material and Method: Patients admitted to Chiang Mai University Hospital with suspected microbial keratitis (non-viral)
were studied retrospectively over a 36-month period (April 2003-March 2006, respectively) (n = 305 cases/310 eyes).
Predisposing factors, causative organisms, patients’ demographic and treatment outcomes were analyzed.
Results : Ocular trauma was the predisposing factor (43.9%) identified most commonly, followed by undetermined causes
(16.1%), ocular surface diseases (13.2%), multiple factors (9.4%), systemic disease (6.8%), ocular surgery (3.9%) and use
of contact lens (3.5%). Cultures of corneal scraping were positive in 25.6% of cases. Both bacteria and fungi were common
pathogens (49.3% and 46.3%, respectively). Pseudomonas aeruginosa (14.9%) and fusarium spp. (26.9%) was the most
common bacterial and fungal pathogen, respectively. Forty-one percent of eyes underwent surgery and the most common
procedure was scleral patch graft (39.8%). A statistically significant predictor of poor visual outcome was an ulcer larger
than 6 mm (OR 3.08, p = 0.002).
Conclusion : Ocular trauma was the most common predisposing factor leading to microbial keratitis. Both bacteria and
fungi were common pathogens. A large lesion at presentation was a significant predictor for poor visual outcome.
Keywords : Bacterial keratitis, Corneal ulcer, Fungal keratitis, Microbial keratitis
