Congenital Night Blindness
Congenital stationary night blindness csnb refers to a group of nonprogressive retinal disorders characterized predominantly by abnormal function of the rod system.
Congenital night blindness. 53 63 congenital stationary night blindness csnb disease. The condition may be x linked the most common form autosomal recessive or autosomal dominant. 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.
Csnb is a heterogenous collection of rare genetic diseases affecting photoreceptors the retinal pigment epithelium rpe or bipolar cells. Night blindness is a type of vision impairment that causes you to experience poor vision at night or in dimly lit environments. Congenital stationary night blindness csnb is recognized by the following codes as per the international classification of diseases icd nomenclature.
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 refers to a group of genetically and clinically heterogeneous retinal disorders. One set the cones perceive bright light.
There may also be moderate to high myopia short sightedness. Night blindness may exist from birth or be caused by injury or malnutrition for example. Congenital stationary night blindness csnb is a rare non progressive retinal disorder.
Congenital night blindness with or without myopia nearsightedness occurs either as a dominant recessive or sex linked hereditary trait and usually remains stable throughout life. Under good lighting conditions there is usually no visual deficit. 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.
Congenital stationary night blindness. 58 deficits of rod and cone systems such as congenital stationary night blindness achromatopsia complete or partial e g blue cone monochromatism and. 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.
Depending on its brightness light is perceived by either of two sets of visual cells located in the retina of the eye. Nyctalopia ˌ n ɪ k t ə ˈ l oʊ p i ə from greek νύκτ nykt night ἀλαός alaos blind not seeing and ὄψ ops eye also called night blindness is a condition making it difficult or impossible to see in relatively low light it is a symptom of several eye diseases. Night blindness inability or a reduced ability to see in dim light.
The eyes not only see more poorly in dim light but are slower to adjust from brightness to dimness.
