Glaucoma treatment devices are disclosed. In various example, the glaucoma treatment devices include multiple microporous layers arranged together to form a microporous body configured to help facilitate evacuation of fluid from a fluid-filled body cavity, and reabsorption of the evacuated aqueous humor by the body through tissue surrounding the glaucoma treatment device. The glaucoma treatment device includes one or more portions configured to resist cellular ingrowth, and one or more portions configured to permit cellular ingrowth. In particular the exterior of may include or be defined by one or more membranes that are porous or otherwise permeable to the fluid of the fluid filled body cavity (referred to hereinafter as diffusion membranes), and that are configured to permit or promote tissue ingrowth while the interior membranes are also microporous and permeable to aqueous humor, but are configured to resist or otherwise minimize the ingrowth and attachment of vessels and tissue structures.
