Authors: Nirojini Sivachandran, Danyal Saeed, Ryan Cho, Cheryl Main, Forough Farrokhyar, Mark Fava
Author Disclosure Block: N. Sivachandran: None. D. Saeed: None. R. Cho: None. C. Main: None. F. Farrokhyar: None. M. Fava: None.

Abstract Body:

Purpose: To determine theepidemiological features and laboratory findings of all those who presented with microbial keratitis between 2007 and June 2017 at Hamilton Regional Eye Institute (HREI).
Study Design: Retrospective Chart Review.
Methods: Patients who were evaluated at the HREI for microbial keratitis and culturing of corneal sample from 2007 to June 2017 were identified by the microbiology department at Hamilton Health Sciences after REB approval. A retrospective chart review was completed. Data was extracted, coded and analysed using SPSS Software Version 22 (IBM Inc).
Results: A total of charts 2909 charts were identified for having cultured eye samples from 2007-2017. Of this we have reviewed 814 charts and 138 charts met the study criteria. Charts were omitted as they were not corneal scrapping, not MK (i.e. DSEK or PKP), repeated entry, electronic charts could not be found, or age under 18. There were 68(49.3%) females and 70(50.7%) males and 58% were older than fifty years of age (p<0.001). Predisposing factors included an ocular exposure i.e. abrasion, trauma etc. (41.3%), contact lens wear (CLW) (23.9%), and ocular surface disease (15.9%). Both the right and left eye were equally affected (47.8%), and in the rare case bilateral involvement (3.6%) was noted. Majority of the infiltrates were 1-4mm (41.3%, p<0.001), peripheral (40.6%, p<0.001), and associated with an epithelial defect (58.7%, p<0.001). Inflammatory burden was documented by the presence of anterior chamber reaction (52.2%) and hypopyon (20.3%). Corneal scrapping was positive in 49.3% with gram positive (73.0%) and gram negative (27.0%) bacteria, viral (4.5%), fungal (9.0%) and acanthamoeba (3.0%). Pre-scrapping antibiotics was used in 39.9%, which had increased to 97.8% with a change in treatment regimen (87%) post-scrapping.Majority of the patients had resolution of their MK (87.5%), though 77.0% had associated scarring and 37.1% had complications i.e. corneal thinning, PKP etc. Evaluation of initial and final visual acuity did not reveal a statistical difference.
Conclusions: Preliminary analysis suggests that despite having resolution of the MK with antimicrobial treatment, there was no significant difference in final visual acuity outcome. This may be in part due to majority of the patients being older, with predisposing risk factors and poor vision at presentation. As well, there may be a selection bias as patients presenting to a tertiary care center likely have more advanced or non-resolving MK.