Inhibits angiogenesis in the vitreous humor of the eye, and therefore represses neovascularization (PubMed:22159013). Binds collagen fibrils (By similarity). May be involved in collagen fiber organization via regulation of other members of the small leucine-rich repeat proteoglycan superfamily (PubMed:29323130). Homodimer. Expressed in cartilage (at protein level) (PubMed:29323130). Expressed in the vitreous collagen, inner limiting membrane, lens capsule, trabecular meshwork, anterior surface of the iris, the area adjacent to the nonpigmented ciliary epithelium, and weakly expressed in the retina of the eye (at protein level) (PubMed:22159013). Expressed in the nonpigmented ciliary epithelium of the eye (PubMed:11527931). Expressed in the presumptive ciliary body during development. O-glycosylated. Sulfated on tyrosine residues. Proteolytically cleaved by MMP1, MMP2, MMP3, MMP7, MMP8, MMP9, ADAMTS4, and ADAMTS5 (By similarity). Proteolytically cleaved by MMP13 (By similarity). Increased organization of cartilage collagen fibers featuring more smaller diameter fibers that are closely packed (PubMed:29323130). Dysregulation of small leucine-rich repeat proteoglycan superfamily members in cartilage, including an increase in Lum and Epyc, and a decrease in Fmod and Prelp (PubMed:29323130). In a surgical osteoarthritis model, a reduction in cartilage degradation and inflammatory markers, decreased loss of cartilage integrity, and reduced synovial membrane thickness (PubMed:29323130). Decrease in vitreous body vaso-obliteration upon hypoxia, and an increase in preretinal neovascularization upon restoration of normoxia (PubMed:22159013). Belongs to the small leucine-rich proteoglycan (SLRP) family. SLRP class III subfamily.