Authors: Grace L. Qiao, Jennifer Ling, Titus Wong, Sonia N. Yeung, Alfonso Iovieno
Author Disclosure Block: G.L. Qiao: None. J. Ling: None. T. Wong: None. S.N. Yeung: None. A. Iovieno: None.

Abstract Body:

Purpose: To determine the epidemiological characteristics, risk factors, and clinical outcomes of Candida keratitis in a tertiary eye care center in Vancouver, Canada.
Study Design: This is a retrospective observational case series.
Methods: We reviewed the medical records of confirmed Candida keratitis cases based on a systematic search of culture positive corneal scraping specimens archived in our microbiology laboratory from 2003 to 2017. We subsequently analyzed the collected data for demographic information, clinical risk factors, comorbidities, presenting characteristics, therapeutic approaches, and final outcomes.
Results: The study identified a total of 40 cases of culture-positive fungal keratitis, of which 25 cases were attributed to Candida (62.5%) from 24 patients. Of these, 21 cases from 20 patients were clinically confirmed to be Candida keratitis. Eight patients were male (40%), and 12 were female (60%). The mean age was 57 years (range 21-87). Candida albicanswas the most common species isolated (48%), followed by Candida parapsilosis(29%), Candida tropicalis(10%), Candida guillermondiiand Candida krusei(4% respectively), and 1 case categorized as “non-albicans.” The proportion of all fungal keratitis cases caused by Candida appears to have increased only in 2016 (75% of 4 cases) and 2017 (100% of 4 cases), though conclusions about trend must be considered with caution due small overall numbers of cases. Pre-existing ocular surface disease was the most common risk factor (71%), followed by contact lens use (52%), recent ocular surgery (38%), and history of ocular trauma (38%). Sixteen patients ultimately required some type of surgical management (76%). Of these, 13 patients received a penetrating keratoplasty (1 optical, 12 therapeutic), and 3 required evisceration or enucleation. Worse presenting visual acuity was highly associated with failing medical management. Good initial visual acuity was predictive for better visual outcomes. Despite theories of higher virulence of albicans species of Candida, we found similar requirements for surgical management between patients with albicans versus non-albicans species, and worse visual outcomes amongst patients with non-albicans Candida keratitis. These poorer outcomes may be attributable to the higher incidence of risk factors - such as pre-existing ocular surface disease and recent ocular surgery - amongst patients who developed non-albicans keratitis.
Conclusions: Candida keratitis presents as a vision-threatening opportunistic infection, which disproportionately affects an already compromised cornea. Early microbiological confirmation is essential to enable prompt initiation of appropriate treatment, as clinical diagnosis is often delayed. Despite medical antifungal therapy, the ocular complications are often devastating and require surgical management.