Figure 7. Schematic representation of IOP-dependent corneal swelling, which was used in the modified “Bead Method” as an indicator of successful injection.

Under normal conditions (A), when the IOP does not exceed the level of stromal swelling pressure (SP), negative imbibition pressure (IP), which is dependent upon an intact endothelial barrier, prevents humor movement toward the corneal stroma and the subepithelial space. When IOP increases (B) and exceeds the level of SP, the corneal endothelial barrier is disturbed, resulting in water accumulation in the stroma and subepithelial layers (corneal edema).