Quantitative Ocular Ultrasound Findings in Microbial Keratitis-Associated Endophthalmitis

Purpose: To assess how ocular ultrasound findings correlate with clinical parameters of patients with infectious keratitis and concern for endophthalmitis and to evaluate the usefulness of ultrasound in managing these patients. Design: Retrospective study. Participants: Seventy-three eyes of 73 patients with microbial keratitis who underwent ultrasound to evaluate for endophthalmitis were included. Methods: Ultrasound images were graded in a masked fashion independently by 2 retina specialists. The degree of vitreous opacities, defined as the largest area within the vitreous cavity occupied by opacities on any single image, were categorized as less than 10%, 10% to less than 50%, 50% to 90%, and more than 90%. The diagnosis of endophthalmitis was defined as severe intraocular inflammation that necessitated obtaining an intraocular culture sample and injection of intravitreal antimicrobials. The demographic and clinical characteristics of this patient cohort were compared. Main Outcome Measures: Vitreous opacities measured quantitatively on ocular ultrasound. Results: The incidence of endophthalmitis in our patients with microbial keratitis who underwent ultrasound was 20.5%. Corneal and intraocular cultures showed positive results in 66.7% and 26.7% of endophthalmitis patients, respectively. A 4-fold increase in the likelihood of treatment for endophthalmitis was observed with increasing vitreous opacity severity (odds ratio, 3.97; confidence interval, 1.9–8.5; P < 0.0001). Endophthalmitis was associated with 50% or more vitreous opacities (P < 0.001), older age (P < 0.001), pseudophakia (P = 0.001), and hypopyon height (P < 0.001). Eye pain, eyelid edema, poor presenting visual acuity, larger corneal ulcer diameter, and causative organisms were not associated with endophthalmitis. Conclusions: Patients with more severe vitreous opacities on ultrasound were more likely to be treated for endophthalmitis. Patients with microbial keratitis, who were older and pseudophakic, were prone to have more severe vitreous opacities.