Factors Associated with Vision Outcomes in Microbial Keratitis: A Multisite Prospective Cohort Study.

Purpose: To investigate factors associated with 90-day vision in patients with microbial keratitis (MK).

Design: Multicenter prospective cohort study recruited patients with MK from the United States and India from July 23, 2020, through May 1, 2024, and followed them for 90 days.

Participants: Individuals ≥ 15 years of age with MK of > 2 mm in stromal infiltrate area without prior corneal surgery or gluing, impending corneal perforation or keratoplasty, no light perception vision, current pregnancy, or incarceration.

Methods: Data on sociodemographics, history, symptoms, clinical measures, and best-corrected visual acuity (BCVA) (as logarithm of the minimum angle of resolution [logMAR] units) at initial and 90-day visits were gathered, with BCVA carried forward for those healed before 90 days. Features were summarized overall and by site. Site-stratified multivariable linear regression models were investigated for associations with 90-day BCVA.

Main Outcome Measures: Ninety-day logMAR BCVA.

Results: Of 479 participants analyzed, after exclusions (n = 31) and participants without a 90-day BCVA (n = 52), participants had an average 90-day BCVA of 1.36 ± 1.40 logMAR in the United States (US) and 0.70 ± 0.99 logMAR in India (P < 0.0001). For the US, worse 90-day BCVA was associated with worse presenting BCVA (β = 0.05-logMAR per 0.1-logMAR unit increase in presenting BCVA; P < 0.0001), longer time until presentation (β = 0.01 per day; P < 0.0001), no contact lens use (β = 0.46; P = 0.0131), and larger stromal infiltrate area (bacterial: β = 0.02 per 1-mm [P = 0.0082]; fungal: β = 0.10 per 1-mm increase in area [P = 0.0002]; P = 0.0017 for interaction). For the India, worse 90-day BCVA was associated with worse presenting BCVA (β = 0.04 logMAR; P < 0.0001), longer delays to presentation (β = 0.03 per day; P = 0.0004), diabetes mellitus (β = 0.41; P = 0.0019), hypopyon (β = 0.27; P = 0.0083), no recent ocular trauma (β = 0.21; P = 0.0370), and larger stromal infiltrate area (fungal: β = 0.03 per 1-mm [P < 0.0001]; bacterial: nonsignificant β [P = 0.07]; P = 0.0001 for interaction).

Conclusions: Initial vision, longer time until presentation, and larger infiltrate size conferred risk for worse 90-day BCVA, whereas other factors were unique. Systems to mitigate care delays and to support access care are needed would support clinicians and improve vision outcomes.

Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.