Achromatopsia

     Achromatopsia is a type of color blindness which the person can only see in black and white and is the rarest form of color blindness.  However, there are many other problems that comes with Achromatopsia besides complete color blindness such as: hemeralopia (the severe sensitivity to light), and  low vision accuity.  There are two forms of Achromtopsia,  Rod Monochromatism, and Blue-cone Monochromatism.  Sometimes, Cone dystrophy can be mistaken as  Blue-cone Monochromacy.

     Rod Monochromatism

     Rod Monochromatismis an autosomal recessive condition, and is the most common form of Achromatopsia.

     Blue-cone Monochromatism

     Blue-cone Monochromatism is a recessive sex-linked condition, and is the rarest form of incomplete Achromatopsia.  About 1 in 100,000 men and 1 in 10 billion women have Blue-cone Monochromatism.

     Rod Monochromatism (RM) vs. Blue-cone monochromatism (BCM)

Hemeralopia:

     RM

          - Has Severe sensitivity to light

     BCM

          - Some have severe light sensitivity wile others have very little light sensitivity

Color Vision:

     RM
          - Has a complete loss of color vision

     BCM

          - Have an incomplete loss of color vision.  Both Blue-cone receptors and Rod receptors function.

          -Can see some colors along the Yellow-Blue axis of the color spectrum.

Nystagmus:

     RM and BCM

          - Appear 3 to 6 months after birth.

          - Usualy lessens or disapears by Adulthood which can cause their vision to improve.

Visual Acuity:

     RM

          -Visual acuity usually ranges from 20/120 to 20/200.  It is also posible for visual acuity to be higher than 20/200 in some cases.

     BCM

          - Visual acuity for BCMs usually ranges from 20/60 to 20/200.  BCMs usually have better visual acuity than RMs because of their functioning S-cones.  However, BCMs can be just as impaired as RMs.

To learn more about Achromatopsia:

          http://www.achromatopsia.info/   https://www.youtube.com/channel/UC25Zkefkoc8Ci8emTVA_-JQ

It's an Achromat thing  ¯\_(ツ)_/¯ :

 https://ambutech.com/ ;