The syndrome is also present in an incomplete form that exhibits milder symptoms, including residual color vision.

The five symptoms associated with achromatopsia are:[citation needed] The syndrome is typically first noticed in children around six months of age due to their photophobia or their nystagmus.

Visual acuity and stability of the eye motions generally improve during the first six to seven years of life – but remain near 20/200.

Coassembly of CNGA3 and CNGB3 produces channels with altered membrane expression, ion permeability (Na+ vs. K+ and Ca2+), relative efficacy of cAMP/cGMP activation, decreased outward rectification, current flickering, and sensitivity to block by L-cis-diltiazem.

Mutations in GNAT2 tend to result in a truncated and, presumably, non-functional protein, thereby preventing alteration of cGMP levels by photons.

Others include the introduction of a sub-conductance, altered single-channel gating kinetics, and increased calcium permeability.

[4] Such loss of function will undoubtedly negate the cone cell's ability to respond to visual input and produce achromatopsia.

This will largely result in haploinsufficiency, though in some cases the truncated proteins may be able to coassemble with wild-type channels in a dominant negative fashion.

Such increased affinity will result in channels that are insensitive to the slight concentration changes of cGMP due to light input into the retina.

This α-subunit then activates a phosphodiesterase that catalyzes the conversion of cGMP to GMP, thereby reducing current through CNG3 channels.

Presumably, then, these proteins are non-functional and, consequently, cone opsin that has been activated by light does not lead to altered cGMP levels or photoreceptor membrane hyperpolarization.

[citation needed] As achromatopsia is linked to only a few single-gene mutations, it is a good candidate for gene therapy.

This form of Sensory substitution maps the hue perceived by a camera worn on the head to a pitch experienced through bone conduction according to a sonochromatic scale.

A 2015 study suggests that achromats who use the Eyeborg for several years exhibit neural plasticity, which indicates the sensory substitution has become intuitive for them.

[15][16] This is the result of a population bottleneck caused by a typhoon and ensuing famine in the 1770s, which killed all but about twenty islanders, including one who was heterozygous for achromatopsia.

[citation needed] It is most frequently caused by physical trauma, hemorrhage or tumor tissue growth.

[20] If there is unilateral damage, a loss of color perception in only half of the visual field may result; this is known as hemiachromatopsia.