Dellen are saucerlike depressions in the corneal surface due to focal stromal dehydration. Desiccation of the corneal epithelium and subepithelial tissues occurs at or near the limbus, adjacent to conjunctival surface elevations such as those produced after recession– resection surgery or in the presence of large filtration blebs. Normal blinking does not wet the involved area properly because the tear film is interrupted by these surface elevations. Patching followed by frequent topical lubrication is most effective in rapidly restoring stromal hydration, although resolution of conjunctival chemosis or bleb revision may be necessary for permanent resolution of dellen.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.