Effects of mitomycin C on glaucoma filtration capsules

One of the leading causes of implantable device failure is build up of scar tissue on the device. Approaches to address this complication range from choosing device materials that prevent cell adhesion to treatment with potent antifibrotic medications such as mitomycin C. We examined the collagen matrix around aqueous shunt implants in rabbit eyes and found the filtration capsule formed around these devices is not composed of scar tissue. Rather collagen deposition is highly organized with collagen bundles oriented along stress axes. We also examined adjacent tissue deposition in mitomycin C treated animals and found decreased vascularization, condensed collagen in Tenon's capsule with more collagen bundles less well formed than those in the control eye of the same animal. The sclera was thicker under the plate than at the opposite side of the same eye. Structural and functional evaluation correlates with the clinical paradox that patients treated with mitomycin C have lower initial pressures with adjunct drug treatment but lower success rates than the control population after 18 months.