Blue Cone Monochromatism

Definition

Definition of Blue Cone Monochromatism
Blue cone monochromatism, also known as S-cone monochromacy, is a recessive disorder that is linked to the X-chromosome. The affected person's green and red cones are missing while the blue cone mechanism is dominant and functioning properly. Cases like these have been called incomplete achromatopsia, wherein color vision is only impaired and not wholly absent.

Symptoms

Symptoms of Blue Cone Monochromatism
Patients with blue cone monochromatism have profound color impairment, but due to the presence of some functioning cone cells in the retina, they have a small residual amount of color vision and slightly better visual acuity. They are often called yellow-blue disorders, but “blue-green disorder” is more accurate since they affect the ability to distinguish colors in the short- and middle-wave regions of the color spectrum.

Causes

Causes of Blue Cone Monochromatism
Blue cone monochromatism is caused by mutations or deletions in visual pigment genes on the X chromosome.

Diagnosis

Diagnosis of Blue Cone Monochromatism
Clinically, the diagnosis was suspected because of x-linked inheritance, the presence of acuities better than 20/200 in two patients and myopia ranging from -1.75 to -15.00 diopters in three patients.

Treatment

Treatment of Blue Cone Monochromatism
Low vision aids can be helpful.  Tinted lenses for photophobia allow for greater visual comfort. A magenta (mixture of red and blue) tint allows for best visual acuity since it protects the rods from saturation while allowing the blue cones to be maximally stimulated.

Prognosis

Prognosis of Blue Cone Monochromatism
Consult with your doctor.

Prevention

Prevention of Blue Cone Monochromatism
Consult with your doctor.