Endophthalmitis in Advanced Microbial Keratitis: Risk Factors and Examination Findings

Purpose: To evaluate clinical and ultrasonographic findings associated with advanced microbial keratitis with concurrent endophthalmitis. Methods: We performed a retrospective analytical study of patients with severe microbial keratitis who underwent ocular ultrasonography for possible endophthalmitis at our institution over a 5-year period. Ocular and medical history, ocular examination findings, microbiology results, and ultrasonographic features were collected. Results: Of the 81 included eyes, 15 were diagnosed with endophthalmitis based on clinical findings and evidence of vitritis on ultrasound. Historical factors and physical examination findings more common in the endophthalmitis group than the keratitis-only group include presenting vision of light perception or no light perception (73.3% vs. 31.8%, P = 0.003), history of cataract surgery (80.0% vs. 45.5%, P = 0.02), and full thickness ulcer or perforation (33.3% vs. 9.1%, P = 0.03). Gram-positive organisms were more common in the endophthalmitis group (60.0% vs. 30.3%, P = 0.04). Ultrasound findings of choroidal thickening and retinal detachment were more common in the endophthalmitis group (26.7% vs. 3.4%, P = 0.01 and 13.3% vs. 8.4%, P = 0.04) in addition to the expected preponderance of membranous and dispersed vitreous opacities in that group. Final visual acuity was worse in the endophthalmitis group (2.3 vs. 3.5 LogMAR, P = 0.02). Conclusions: Diagnosing endophthalmitis can be difficult in eyes with advanced microbial keratitis, and the visual outcomes are often extremely poor. Clinicians should have a particularly high index of suspicion in eyes presenting with light perception or no light perception vision, history of cataract extraction, full thickness ulcer or perforation, or choroidal thickening or retinal detachment on ultrasound.