Symptoms as an Indicator of Microbial Keratitis Severity and Its Association With Visual Acuity.

Objective: Microbial keratitis (MK) is a vision-threatening and often painful corneal infection. This study aims to quantify severity of symptoms of MK at presentation and investigate their association with visual acuity (VA).

Methods: The Automated Quantitative Ulcer Analysis (AQUA) study recruited MK patients from two sites (University of Michigan and Aravind Eye Care System). At presentation, best-corrected VA was recorded. Patients were surveyed on severity of symptoms on a five-point scale for pain or a four-point scale for redness, light sensitivity/glare, and blurry vision. The association between symptom severity and VA was tested with Spearman correlations (r) and Kruskal-Wallis tests.

Results: Seven hundred three patients with MK were enrolled in the AQUA study from July 2020 to November 2022. Presenting logMAR VA had a median value of 1.3 (Snellen equivalent, 20/400). Most patients reported pain (98.7%), redness (99.1%), light sensitivity/glare (98.4%), and blurry vision (99.2%). Visual acuity showed a significant correlation with cumulative symptom severity (spearman r=0.15, P <0.0001). For those who reported pain and blurry vision, VA worsened with increasing symptom severity ( P <0.0001).

Conclusions: Presenting VA showed a significant positive correlation with cumulative symptom severity and the individual symptoms of pain and blurry vision. Patient-reported symptoms at MK presentation may indicate disease severity.