Abstract: The invention provides a cinnamic acid derivative having a novel spacer introduced into cinnamic acid which is photodimerizable, a cinnamic acid-polysaccharide derivative photocurable with high sensitivity and efficiency obtainable by introducing the above cinnamic acid derivative into a host polysaccharide such as a glycosaminoglycan, and a photocrosslinked cinnamic acid-polysaccharide derivative obtainable by exposing the same cinnamic acid-polysaccharide derivative to ultraviolet light irradiation.

Abstract: The invention provides a cinnamic acid derivative having a novel spacer introduced into cinnamic acid which is photodimerizable, a cinnamic acid-polysaccharide derivative photocurable with high sensitivity and efficiency obtainable by introducing the above cinnamic acid derivative into a host polysaccharide such as a glycosaminoglycan, and a photocrosslinked cinnamic acid-polysaccharide derivative obtainable by exposing the same cinnamic acid-polysaccharide derivative to ultraviolet light irradiation.

Abstract: A photocured crosslinked-hyaluronic acid contact lens which comprises a photocured crosslinked-hyaluronic acid derivative produced by the formation of a crosslinked cyclobutane ring by light irradiation from mutual photoreactive crosslinking groups of a photoreactive hyaluronic acid derivative in which the photoreactive crosslinking groups are linked to hyaluronic acid, wherein the photoreactive crosslinking groups are introduced into functional groups of hyaluronic acid via a spacer group, and the contact lens has a water content of 80 to 99% and shape compatibility and tissue affinity for the eyeball. A process for preparing a photocured crosslinked-hyaluronic acid contact lens which comprises molding the photoreactive hyaluronic acid derivative into a shape that fits to the eyeball, and subsequently irradiating the shaped product with light to effect crosslinking between the mutual photoreactive crosslinking groups.