Gene Therapy is a futuristic technology that uses viruses (viral vectors) to inject revised Genes into cells that have undesired forms (alleles) of those Genes. For example, a dysfunctional allele of the M-opsin gene leads to Deuteranopia. Replacing that with the allele of a Color Normal could fix the individual’s Colorblindness.
This technology was used to give a dichromatic squirrel monkey functional trichromacy and therefore could be used to cure Dichromacy in humans. However, the potential adverse side effects of sub-retinal injections and the small benefit of “upgrading” from Dichromacy to Trichromacy has stalled human development. Instead, human trials have started for the Gene Therapy of some forms of Achromatopsia, which would give a much larger benefit for the same amount of risk. Once the technology can be trialed in Achromats, it may become safe enough to use in Dichromats.