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Night Blindness

 

Patients who suffer from nyctalopia, or more commonly known as night blindness, experience poor vision during the night or in poorly lit environments. It is a form of vision impairment and occurs as a symptom of numerous congenital (present from birth) and inherited retinal diseases or as a result of vitamin A deficiency.


Vitamin A deficiency contributes to night blindness by making the cornea very dry, thus damaging the retina and cornea. As a result, the blood vessels running through these areas are affected. These veins carry neurons between the optic nerve and the brain. Hence, neurons die when the veins are damaged, and the brain does not receive visual information. 


The effects of a damaged retina and cornea is exacerbated at night as the near absence of blue light renders one colour blind. This effect contributes to “night blindness”.


Sources:

https://www.webmd.com/eye-health/night-blindness

https://www.optometrists.org/general-practice-optometry/what-causes-night-blindness/night-blindness-treatments-and-prevention/

https://www.britannica.com/science/night-blindness


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