• opticin
• vitreous
• immunohistochemistry
• basement membrane

It is reassuring to realise that there are still new molecules to be discovered using classic biochemical methods rather than the blockbuster genomic approach. Opticin is an eye specific molecule discovered by Reardon and colleagues in 2000¹ using a 4 M guanidine hydrochloride extract from bovine vitreous collagen fibrils to prepare peptides as a starting point for molecular cloning. Almost simultaneously, a separate group of researchers discovered an iris specific molecule which they termed oculoglycan² and was later found to be identical with opticin. In this issue of the BJO (p 697), Ramesh et al describe more fully the distribution of opticin in the human eye. Opticin was found to be present in significant quantities in several ocular tissues, particularly the ciliary body, the iris, and the anterior vitreous close to the pars plana. It is a proteoglycan of the small leucine rich repeat (LRR) family located in the extracellular matrix.

The role of opticin is not clear. In the vitreous …