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A collagen matrix implant offered a physiological environment conducive to normal healing, prevented the collapse of the subconjunctival space during the period of normal wound contraction and provided a certain amount of weight initially on the scleral flap to prevent a shallow anterior chamberThe post-operative scarring response following filtration surgery remains a major barrier to achieving surgical success. Current antifibrotic agents available are not ideal as they can lead to sight-threatening complications such as hypotony and bleb-related endophthalmitis. Chen et al. (1314) investigated the effect of a biodegradable, porous collagen containing matrix on intraocular pressure control and wound healing following glaucoma filtration surgery in an animal model. Both eyes from each animal underwent modified trabeculectomies in the study. In the right eyes, a matrix implant was placed on top of the comparatively loosely tied scleral flap before conjunctival closure. The left eyes served as surgical controls with sutures to the flap tied with normal tension. The intraocular pressures were measured on days 3, 7, 14, 21 and 28. The animals were sacrificed at these time points for histological analysis.
Intraocular pressure remained significantly lower at all time points in the implant treated group compared to the controls. The implant was observed to start degrading after day 7 following surgery with only a few myofibroblasts identified in the subconjunctival space. Furthermore, random collagen fibres with large extracellular spaces were noted to replace the degraded implant. This contrasted with the surgical control, which on day 28 demonstrated a minimal bleb cavity densely packed with collagen and populated by numerous myofibroblasts. The authors concluded that the collagen matrix implant offered a physiological environment conducive to normal healing, prevented the collapse of the subconjunctival space during the period of normal wound contraction and provided a certain amount of weight initially on the scleral flap to prevent a shallow anterior chamber.