Night Blindness – Causes

Night blindness (nyctalopia) is a condition in which there is impaired vision in dim light. The causes of night blindess are:

  • Conditions affecting the functioning of rods (as rods are involved in night / scotopic vision)
    • Vitamin A deficiency
    • Retinitis pigmentosa (and other tapetoretinal degenerations)
    • Oguchi disease (congenital stationary night blindness)
    • Congenital high mypoia
    • Familial congenital night blindness
  • Certain conditions affecting transparency of visual media
    • In dim light, the pupils dilate so as to allow more light to reach the retina
    • In case of peripheral corneal opacities and paracentral lenticular opacities, there is obstruction to the passage of light when pupils are dilated
  • Conditions causing delayed dark adaptation
    • Advanced primary open angle glaucoma

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