["En face" anterior segment optical coherence tomography findings in acute corneal hydrops]

To study the corneal morphological characteristics of acute hydrops by analyzing anterior segment optical coherence tomography (AS-OCT) "en face" images.

Four patients presenting with acute hydrops were examined at different stages, respectively after 1 day, 1 week, 3 weeks and 6 months. All patients had a complete ophthalmic evaluation including "en face" AS-OCT examination. In vivo confocal microscopy (IVCM) and histological analysis of the cornea obtained after penetrating keratoplasty were also performed in one patient.

The "en face" AS-OCT showed that the early edema in acute hydrops corresponded to multiple epithelial microcysts associated with large intra-stromal lacunae. We also observed that, in association with the disappearance of the microcysts and lacunae, "en face" OCT demonstrated subepithelial scars in the form of weakly reflective, fine, interlaced linear opacities. These opacities subsequently increased in thickness resulting in a dense subepithelial network. These findings were consistent with the results of histological and IVCM studies.

"En face" AS-OCT allows for precise study of the tissue changes occurring in acute corneal hydrops. Besides a better understanding of this rare complication of keratoconus, this new imaging technique may help clinicians to identify the corneal structural changes, which place keratoconus patients at risk of corneal hydrops.