A curable composition and an optical element including a cured product thereof. The curable composition includes an episulfide compound and an aromatic heterocyclic compound.

A composition for a high refractive index, low dispersion resin for a close-contact double layer-type composite diffractive optical element that is highly photocurable and provides a high productivity, and a close-contact double layer-type composite diffractive optical element using such composition are provided. A composition for a high refractive index, low dispersion resin for a close-contact double layer-type composite diffractive optical element includes a thiol compound represented by general formula (1) or an oligomer synthesized by use of a thiol compound represented by general formula (1) (A component); and an ene compound including two or more polymerizable unsaturated bonds (B component). (In the formula, p represents an integer of 2 to 5; X.sub.p and Z.sub.p independently represent a hydrogen atom or a mercaptomethyl group; a ratio of sulfur atoms in a molecule is 40 to 80% by mass; and the number of thiol groups is 3 or larger.).

The present invention discloses a dyeable 1.74 resin lens and a preparation method thereof. The resin lens includes a module layer with a refractive index being 1.74, a dyeable layer with a refractive index being 1.60 is poured on an upper surface of the module layer, an upward curved degree of the dyeable layer is the same as an upward curved degree of the module layer, and a center thickness of the dyeable layer is 0.5-1.2 mm. According to the dyeable 1.74 resin lens of the present invention, a layer of dyeable 1.60plus resin lens is attached to a surface of a 1.74 lens, dyeing performance is good, a visible light transmittance can reach 10-30%, and the blank that the 1.74 lens cannot be dyed is filled.

A zwitterionic compound has a structure of following formula (1), formula (2), formula (3), or formula (4):

##STR00001## R.sub.1 is —O.sup.−, —(CH.sub.2).sub.aSO.sub.3.sup.−, or —(CH.sub.2).sub.bCO.sub.2.sup.−, a is 1 to 10, and b is 1 to 10. R.sub.2 and R.sub.3 are each independently an alkyl group or a phenyl group. x, z, and v are each independently 1 to 20. y and t are each independently 0 to 10.

A zwitterionic compound has a structure of following formula (1), formula (2), formula (3), or formula (4):

##STR00001## R.sub.1 is —O.sup.−, —(CH.sub.2).sub.aSO.sub.3.sup.−, or —(CH.sub.2).sub.bCO.sub.2.sup.−, a is 1 to 10, and b is 1 to 10. R.sub.2 and R.sub.3 are each independently an alkyl group or a phenyl group. x, z, and v are each independently 1 to 20. y and t are each independently 0 to 10.

A random copolymer comprising the monomer units A and B. In this random copolymer A comprises ##STR00001##
and B comprises ##STR00002##
Additionally, R1 R2, R3 and R4 are side chains independently selected from the group consisting of: H, Cl, F, CN, alkyl, alkoxy, alkylthio, ester, ketone and aryl groups. X1 and X2 are different and at least one is a Cl and the other is selected from the group consisting of: H, F, CN, alkyl, alkoxy, ester, ketone, amide and aryl groups.

A random copolymer comprising the monomer units A and B. In this random copolymer A comprises ##STR00001##
and B comprises ##STR00002##
Additionally, R1 R2, R3 and R4 are side chains independently selected from the group consisting of: H, Cl, F, CN, alkyl, alkoxy, alkylthio, ester, ketone and aryl groups. X1 and X2 are different and at least one is a Cl and the other is selected from the group consisting of: H, F, CN, alkyl, alkoxy, ester, ketone, amide and aryl groups.

A composition containing: a compound (a) represented by Formula (1):

##STR00001##

wherein Ar represents an aromatic ring, m represents an integer of 2 to 8, n represents an integer of 0 to 6, provided that m+n is equal to or less than a number of carbon atoms that constitute the aromatic ring, and R.sup.1 each independently represents an alkylthio group, an epoxyalkylthio group, a thiol group, a halogen group, a hydroxy group, a dialkylthiocarbamoyl group, or a dialkylcarbamoylthio group; and a polythiol (b).

A composition containing: a compound (a) represented by Formula (1):

##STR00001##

wherein Ar represents an aromatic ring, m represents an integer of 2 to 8, n represents an integer of 0 to 6, provided that m+n is equal to or less than a number of carbon atoms that constitute the aromatic ring, and R.sup.1 each independently represents an alkylthio group, an epoxyalkylthio group, a thiol group, a halogen group, a hydroxy group, a dialkylthiocarbamoyl group, or a dialkylcarbamoylthio group; and a polythiol (b).

A biosensing composition having sensing glucose content is provided, including a substrate, glucose oxidase, an antioxidant, heme-protein, and a molecular chromogenic chromophore. In addition, a contact lens having sensing glucose content and a method of preparation thereof are provided, so as to achieve the effect of maintaining a low discoloration in normal blood sugar and obvious discoloration in high blood sugar.