Authors: Prem A. H. Nichani¹, Benjamin Solomon², Tanya Trinh³, Michael Mimouni⁴, David Rootman¹, Neera Singal¹, Clara C. Chan¹. ¹Department of Ophthalmology & Vision Sciences, Temerty Faculty of Medicine, University of Toronto, 2Undergraduate Medical Education, Temerty Faculty of Medicine, University of Toronto, 3Sydney Hospital and Sydney Eye Hospital, 4Rambam Health Care Campus.

Author Disclosure Block: P.A.H. Nichani: None. B. Solomon: None. T. Trinh: None. M. Mimouni: None. D. Rootman: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Alcon, Johnson & Johnson. N. Singal: None. C.C. Chan: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Alcon, Allergan, Bausch & Lomb, Johnson & Johnson, Labtician Thea, Santen, Shire, Tearlab, Zeiss. Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); Alcon, Allergan, Bausch & Lomb, Labtician Thea, Santen, Shire, Tearlab.

Title: Investigating the Role of Inflammation in Keratoconus: A Retrospective Analysis of 551 Eyes

Abstract Body:

Purpose: Keratoconus (KCN) is classically defined as a noninflammatory, progressive, corneal ectasia with high visual morbidity and is a common indication for corneal transplantation. However, KCN was more recently associated with low-level chronic inflammatory components. This study aimed to further evaluate the association between inflammation and KCN severity by assessing tear film biomarkers. 

Study Design: Retrospective noncomparative chart review of consecutive patients (July 2016 - February 2020) referred to a tertiary KCN centre. 

Methods: Data abstracted included demographics (age at first visit, sex), self-reported history and risk factors collected via a standardized intake form (atopy, symptoms, ocular history, systemic comorbidities, medication use, eye-rubbing habits, Symptom Assessment Questionnaire iN Dry Eye (SANDE) responses), corrected distance visual acuity, tomography and topography values, tear film osmolality, and MMP9 testing results. All patients with a confirmed diagnosis of KCN and available MMP9 testing results were included. Worst-eye analysis based on Pentacam tomography maximum keratometry (Kmax) values was conducted using independent t tests for continuous variables and Pearson chi-squared tests for categorical variables. A p-value ≤ 0.05 was considered as significant. 

Results: Results: Of 551 patients, 70.1% were males, mean age was 30.19 ± 9.77 years, and mean SANDE score 3.57 ± 2.70. In a worst-eye analysis, 49.5% were right eyes, 55.2% were MMP-9 positive,