We don't have synonyms for dichromic yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are achromic, dichromatic and diachronic.
(adj) :
furnishing or giving two colours; said of defective vision, in which all the compound colours are resolvable into two elements instead of three
(adj) :
furnishing or giving two colours; said of defective vision, in which all the compound colours are resolvable into two elements instead of three