OPTC (opticin) encodes a small leucine-rich repeat proteoglycan (SLRP) that functions primarily in extracellular matrix organization and regulation of angiogenesis. The protein demonstrates protective effects in cartilage, as OPTC deficiency in a mouse osteoarthritis model provided significant protection against cartilage degradation through upregulation of lumican and epiphycan and downregulation of fibromodulin, resulting in better organized collagen fibers and reduced inflammatory processes 1. OPTC appears to function through regulation of other SLRP family members, contributing to collagen fibril organization in tissues including sclera and vitreous 2. Disease relevance includes potential involvement in primary open-angle glaucoma, where mutations in OPTC were detected in patients but not controls, including a silent mutation that reduced both mRNA and protein expression levels 3. However, screening for high myopia found minimal evidence for OPTC involvement, with only one novel variation detected among 93 patients 2. The protective role in cartilage degradation suggests OPTC evaluation could serve as a prognostic tool for osteoarthritis classification, though clinical applications remain to be established 1. Additional research is needed to fully characterize its therapeutic potential in musculoskeletal and ocular diseases.