The invention relates to a dye composition for lens. The dye composition comprises a dichloro-quinoxaline-type pigment matrix, a hydrophilic polymer matrix and a vinyl-type binding agent.

The manufacturing factors which have most influence on the emulsion characteristics are the chemical composition and dye-sensitisation of the emulsion.

A color forming composition or composite can include a polymer matrix, a thermally modifiable fluoran leuco dye having a latent developer attached thereto, and a radiation absorber.