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

Dim vision in the evening and night, medically known as nyctalopia or night blindness, is primarily caused by a deficiency of Vitamin A [t2][t5]. Vitamin A is essential for the production of rhodopsin, a pigment in the retina that allows the eye to see in low-light conditions [t4]. Without sufficient Vitamin A, the retina becomes less responsive to dim light, leading to impaired vision at night [t10]. This deficiency can progress to more severe conditions like xerophthalmia (dryness of the conjunctiva and cornea) and keratomalacia if left untreated [t5]. While Vitamin B12 deficiency is linked to optic neuropathy and Vitamin C deficiency can affect overall eye health, they are not the primary causes of night blindness [t1]. Therefore, Vitamin A is the critical nutrient required for maintaining healthy night vision [t8].

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC3880510/