Dim-vision in the evening and night results from the deficiency of which one of the following ?

Dim vision in the evening and night, clinically known as nyctalopia or night blindness, is primarily caused by a deficiency of Vitamin A [t1][t7]. Vitamin A (retinol) is a critical precursor for the synthesis of rhodopsin, a light-sensitive photopigment located in the rod cells of the retina [t10]. Rods are responsible for vision in low-light or dim conditions, while cones handle daytime and color vision [t2][t10]. When Vitamin A levels are insufficient, rhodopsin cannot be adequately regenerated, leading to impaired rod function and the inability to see clearly in the dark [t2][t3]. This condition is often the earliest clinical manifestation of xerophthalmia, a progressive eye disease that can lead to permanent blindness if untreated [t2][t4]. Other options like Vitamin B12, E, and C are essential for nerve health, antioxidant protection, and collagen synthesis, respectively, but are not directly linked to night blindness [c1].

Sources

1. [1] https://pubmed.ncbi.nlm.nih.gov/40970261/
2. [2] https://www.ncbi.nlm.nih.gov/books/NBK431094/
3. [3] https://pmc.ncbi.nlm.nih.gov/articles/PMC8172435/
4. [4] Science-Class VII . NCERT(Revised ed 2025) > Chapter 6: Adolescence: A Stage of Growth and Change > Science and Society > p. 80