Symptom Severity and Association with Visual Acuity at Microbial Keratitis Presentation

Abstract

Purpose : Microbial keratitis (MK) is a vision-threatening corneal infection that can cause bothersome symptoms, including vision changes and pain. The aim of this study was to quantify severity of symptoms for MK patients at presentation and investigate their association with visual acuity (VA).

Methods : The Automated Quantitative Ulcer Analysis (AQUA) study recruited patients with MK from two sites (University of Michigan, Aravind Eye Care System). Best-corrected VA was measured via Snellen chart for the affected eye of patients at presentation. Patients were surveyed on their initial symptoms and reported severity on a 5-point scale for pain (none [0] to very severe [5]) or a 4-point scale for redness, light sensitivity/glare, and blurry vision (not at all a problem [1] to very much a problem [4]). Cumulative symptom severity was calculated as the sum of individual symptom severity (0 to 17). Patient demographics, presenting VA converted to logMAR, and initial symptomology were summarized. The association between symptom severity and VA was tested with spearman correlations (r) and Kruskal-Wallis tests.

Results : 703 patients were enrolled in the AQUA study from July 2020 to November 2022 and completed baseline assessment (17% UM, 83% AECS). Patients were on average 52.5 years old (standard deviation=14.8), 61.7% Male, 15.2% White/1.3% Black/82.8% Asian, and 0.7% were Hispanic. Presenting logMAR VA had a median value of 1.3 (Snellen equivalent, 20/400; interquartile range [IQR], 20/118 to 20/4000). Most patients reported pain (98.7%), redness (99.1%), light sensitivity/glare (98.4%), or blurry vision (99.2%), with a median cumulative symptom severity score of 15 (IQR 13 to 16). VA showed a significant correlation with cumulative symptom severity, such that as logMAR VA worsened, cumulative severity also worsened (spearman r=0.15, p<0.0001). For those who reported pain, VA worsened with increasing pain such that for those with mild/moderate/severe/very severe pain, median logMAR VA was 0.90, 1.08, 1.30, and 1.78, respectively (p<0.0001). Blurry vision showed similar results (p<0.0001).

Conclusions : Most MK patients present with ocular symptoms, ranging from mild to severe. Presenting VA showed a significant positive correlation with cumulative symptom severity, and specifically with the individual symptoms of pain and blurry vision. Clinicians should consider symptom management when initiating treatment for MK.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.