Oligocone Trichromacy

A very rare syndrome first described in [1973], which expresses itself as a very mild form of Incomplete Achromatopsia, with sub-par (uncorrectable) visual acuity & mild photophobia, but no clear color vision defects (according to anomaloscope).

The cause is considered to be a uniform decrease in the density of cones in the retina. The uniform decrease of all three cone types (the ratios in the cone mosaic are kept constant) means the color vision is not greatly affected. Genes responsible are hypothesized to be the same as those responsible for Achromatopsia (Michaelides 2004).