Achromatopsia is a hereditary disease caused by the lack of cone receptors in your eyes. People who have achromatopsia cannot see color and may have bad vision in bright light. Many people who suffer from this condition wear tinted glasses in areas with bright light or outdoors in the sunlight to help improve their vision.

Congenital Achromatopsia

In your eyes, cones are the receptors on your retina that sense color. Cones are located mainly in the center of your retina and comprise most of the receptors that give you vision. Rods are located near the outside of your retina and sense light and darkness. They are not as sensitive as cones. People born without cones in their eyes have congenital achromatopsia.

Founder Effect

The Pingelapese people who live on the Caroline Islands in the Pacific have a high occurrence of achromatopsia. Neurologist Oliver Sacks, who studied the Pingelapese, theorized that the cause of this is the fact that much of the population was killed during a typhoon in 1780. Many of the remaining population had the gene that carries the defect that causes achromatopsia. Dr. Sacks called this the Founder Effect because of the growth of the population from a small number of parents.

Sex-Linked Gene

More males than females suffer from achromatopsia. One in eight males has achromatopsia as compared to one in 10 females. Females may carry the gene, but it affects more males.

Diseases

Some diseases may cause acquired colorblindness. These include diabetes, glaucoma and Parkinson's disease. One or both eyes may be affected.

Medications

Some blood pressure and heart medications can affect vision and cause colorblindness by damaging the cones in your eyes.

Aging

The natural aging process can affect eyesight by the degeneration of your cone receptors.

Source:

Medicine Net.com: Achromatopsia

Medicine Net.com; Colorblindness

Mayo Clinic.com; Poor Color Vision