Abstract
Purpose :
Using slit lamp examination alone, it can be difficult to determine whether bacterial (BK) or fungal keratitis (FK) is responding to antimicrobial treatment. In vivo confocal microscopy (IVCM) provides a high-resolution view of corneal ultrastructure during healing. In this study we identified IVCM morphological features associated with clinical outcome in BK and FK.
Methods :
Prospective observational cohort study of adults ≥18 years with culture-positive unilateral BK or FK ≥3mm in diameter presenting to Aravind Eye Hospital, India, from February 2012 to February 2013. HRT3 IVCM performed at baseline, days 7, 14 and 21 post-enrolment (+/- 3 days where possible) and images assessed by grader masked to outcome/microbiology. Association of IVCM morphological features with good outcome (healed/improving by final visit) or poor outcome (enlarged ulcer size, perforation or surgical intervention performed, e.g. glue/keratoplasty, by final visit) assessed using logistic regression.
Results :
209 participants enrolled (178 FK, 15 BK, 16 culture/light microscopy/IVCM-negative), of whom 107 healed/improved and 102 were worse/perforated at final visit; IVCM imaging was obtained for 164 participants at final visit. Worsening ulcers were associated with an interconnected stellate cellular IVCM appearance with no nuclei in anterior stroma (OR 2.03, 95% CI: 1.02-4.04, p=0.043) or posterior stroma (OR 14.40, 95% CI: 1.48-140.00, p=0.022), and at final visit with honeycomb distribution of inflammatory cells in anterior stroma (OR 5.33, 95% CI: 1.64-17.37, p=0.005). At the final visit, in FK, worsening ulcers were associated with intact hyphae in anterior stroma (OR 3.37, 95% CI 1.41-8.07, p=0.006) and posterior stroma (OR 20.86, 95%CI 1.55-281.12, p=0.022). Healing ulcers were associated with anterior stromal scarring at final visit (OR 4.88, 95% CI: 2.02-11.83, p<0.001).
Conclusions :
IVCM imaging can reveal corneal morphological changes associated with ulcer outcome. Further studies are required to validate these findings as prognostic biomarkers.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.