To obtain an optical transparent film markedly reduced in optical defects by adding a specified alcohol to a casting solution to suppress foaming due to moisture in the production of an optical transparent film by a solution cast film formation process.

This film is obtained by adding a 1-8C alkyl alcohol to a casting solution in producing an optical transparent film by a solution casting film formation process. Examples of materials for forming the film include polycarbonates, polystyrene and polymethacrylates. Examples of the solvents for dissolving these polymers include methylene chloride (for polycarbonates) and methyl ethyl ketone and toluene (for polystyrenes).