Stationary Night Blindness
X linked congenital stationary night blindness xlcsnb is a disorder of the retina people with this condition typically experience night blindness and other vision problems including loss of sharpness reduced visual acuity severe nearsightedness myopia nystagmus and strabismus color vision is typically not affected.
Stationary night blindness. Congenital stationary night blindness csnb refers to a group of nonprogressive retinal disorders characterized predominantly by abnormal function of the rod system. The term sensory nystagmus has been used to describe these types of nystagmus although in some diseases it is not entirely clear whether the sensory deficits cause the nystagmus or whether the nystagmus is intrinsic to the disease. An inherited eye disorder that is not progressive stationary and principally affects the rod photoreceptors in the retina impairing night vision.
Congenital stationary night blindness csnb is a rare non progressive retinal disorder. There may also be moderate to high myopia short sightedness. Night blindness is a feature of many pigmentary and other retinal disorders most of which are progressive.
The condition may be x linked the most common form autosomal recessive or autosomal dominant. Congenital stationary night blindness csnb is usually diagnosed based on the owner s observations but some horses have visibly abnormal eyes. Csnb is a heterogenous collection of rare genetic diseases affecting photoreceptors the retinal pigment epithelium rpe or bipolar cells.
The disorder is diagnosed by electroretinography. In horses csnb has been linked with the leopard complex color pattern since the 1970s. Seventeen different genes with more than 360 different mutations and more than 670 affected alleles have been associated with csnb including genes coding for proteins of the phototransduction cascade those important for signal transmission from the photoreceptors to.
These vision problems are usually evident at birth but tend to be. Congenital stationary night blindness csnb is recognized by the following codes as per the international classification of diseases icd nomenclature. Takeaways congenital stationary night blindness csnb is the inability to see in low to no light conditions.
Under good lighting conditions there is usually no visual deficit. This includes horses from the appaloosa miniature horse and knabstrupper breeds among others. Other breeds without leopard complex spotting have also been reported to have this condition and.
Congenital stationary night blindness. People with csnb often have difficulty adapting to low light situations due to impaired photoreceptor transmission these patients may also have reduced visual acuity myopia nystagmus and strabismus csnb has two forms complete also known as type 1 csnb1 and incomplete also known as type 2 csnb2. Poorly aligned eyes dorsomedial strabismus or involuntary eye movement nystagmus.
Congenital stationary night blindness csnb refers to a group of genetically and clinically heterogeneous retinal disorders. However there is also a group of genetically heterogeneous disorders with generally stable scotopic defects and without rpe changes known as congenital stationary night blindness csnb.
