Predisposing Factors, Microbial Characteristics, and Clinical Outcome of Microbial Keratitis in a Tertiary Centre in Hong Kong: A 10-Year Experience

Table 1

Risk factors for microbial keratitis.

Risk factors	Number of cases^1	Most common microbial isolate
(1) Contact lens use	111	Pseudomonas
(2) Ocular trauma	27	Staphylococcus aureus
(3) Presence of keratopathy or ocular surface disease	82	Coagulase-negative Staphylococcus
(i) Presence of corneal scars or irregular ocular surface	19 (23.2%)
(ii) History of corneal surgical procedures	11 (13.4%)
(iii) Exposure keratopathy	10 (12.2%)
(iv) Bullous keratopathy	7 (8.5%)
(v) Superimposed infection following an epithelial defect	7 (8.5%)
(vi) Superimposed infection following active herpetic keratitis	6 (7.3%)
(vii) Dry eyes with corneal involvement	5 (6.1%)
(viii) Neurotrophic keratopathy	3 (3.7%)
(ix) Others	13 (15.9%)
(4) Systemic conditions^2	48^2	Coagulase-negative Staphylococcus
Immunocompromised state
(i) Diabetes mellitus	25 (52.1%)
(ii) End-organ failure	8 (16.7%)
(iii) Use of immunosuppressant including steroids	7 (14.6%)
(iv) Terminal malignancies	3 (6.3%)
Mental illness with poor self-care^3	17 (35.4%)

214 cases (82.3%) had at least 1 risk factor identified. 55 cases (21.2%) had more than 1 risk factor.
²Some cases had multiple conditions.
³This group included moderate-to-severe mental retardation, moderate-to-severe dementia, and schizophrenia with self-neglect.