1. Literature and database search and summary of our own molecular genetic analyses in patients affected by achromatopsia, blue cone monochromatism, and cone and cone-rod dystrophy.

2. A genetic examination is very helpful to distinguish achromatopsia from other stationary cone disorders like X-linked recessive blue cone monochromatism and from progressive cone and cone-rod dystrophies.

3. Conclusion: Differential diagnosis includes all diseases associated with congenital nystagm, such as aniridia, diseases of the optic nerve, albinism and all forms of hereditary cone dysfunction, cone dystrophies and complete and incomplete congenital stationary monochromatism.