Identification of risk factors for persistent corneal edema associated with acute corneal hydrops in keratoconus.

Purpose: The aim of this study was to investigate the clinical characteristics of acute corneal hydrops (ACH) in patients with keratoconus and to examine the risk factors for persistent corneal edema.

Study design: Retrospective observational study.

Methods: The study included 98 patients (106 eyes) diagnosed with ACH between February 2009 and August 2023 at Kyoto Prefectural University of Medicine. Seventy-seven eyes with clear data on both onset and resolution were analyzed for the risk factors for persistent corneal edema. Clinical characteristics, duration of corneal edema, and associated risk factors such as seasonal variations, edema area, allergic diseases, eye rubbing, and neurodevelopmental disorders (including Down syndrome) were collected and analyzed.

Results: The study included 90 male (91.8%) and 8 female (8.2%) patients. The mean (SD) age at ACH onset was 33.3 (13.8) years (range, 14-80). ACH occurred most prevalently during the spring season (n = 39, 36.8%). Allergic diseases were present in 59 eyes (55.7%); eye rubbing, in 58 eyes (54.7%); and neurodevelopmental disorders, in 9 eyes (8.5%). Corneal edema resolved within 3 months in 55 eyes (71.4%), whereas it persisted for over 3 months in 22 eyes (28.6%). Multivariate analysis showed that a large edema area, ≥50%, was a significant risk factor for persistent corneal edema of more than 3 months in ACH patients (odds ratio, 7.41; 95% CI, 1.95-33.02; P = .005).

Conclusion: Large corneal edema at ACH onset carries a high risk of persistent corneal edema. These patients should be managed more carefully to resolve the corneal edema earlier.