Has a role in the formation and organization of the extracellular matrix. In the eye, it functions as a mediator of dexamethasone-induced matrix deposition in the trabecular meshwork, the tissue responsible for the outflow of the ocular aqueous humor and for the maintenance of intraocular pressure (By similarity). Is a negative regulator of angiogenesis in the cornea, and plays a major role in maintaining corneal avascularity and transparency (PubMed:25622036). Homotetramer; disulfide-linked.