Inhibits angiogenesis in the vitreous humor of the eye, and therefore represses neovascularization (By similarity). Binds collagen fibrils (PubMed:12951322, PubMed:10636917). May be involved in collagen fiber organization via regulation of other members of the small leucine-rich repeat proteoglycan superfamily (By similarity). Homodimer. O-glycosylated (sialylated oligosaccharides). Sulfated on tyrosine residues. Proteolytically cleaved by MMP1, MMP2, MMP3, MMP7, MMP8, MMP9, ADAMTS4, and ADAMTS5 (By similarity). Proteolytically cleaved by MMP13 (PubMed:18164633). Belongs to the small leucine-rich proteoglycan (SLRP) family. SLRP class III subfamily.