Vitreous, drug loss

Retinal damage appears to be an undesirable companion of transscleral iontophoresis. Retinal edema occurs within seconds of current application (56). Disruption of the normal retinal architecture, hemorrhagic necrosis, fibrosis, and RPE hyperplasia are evident beneath the iontophoretic site (68,69), and multiple applications exacerbate these injuries (70). Loss of tissue integrity, although spatially confined, may permit drug entry into the vitreous cavity or even the anterior segment tissues. Drug stability to possible electrochemical reactions is another possible limitation of this approach. 

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