Night Vision Roadmap

Vitamin A/Retinol, Night Vision Loss, And Dry Eye Disease One of the first and foremost reasons for night vision loss is Vitamin A deficiency. A 2022 review titled “Vitamin A Deficiency” states: “[Vitamin A] Deficiency can lead to night blindness due to poor regeneration of visual pigment [rhodopsin] in retinal rods. If the deficiency is allowed to persist, the rods will degenerate, and xerophthalmia [dry eye syndrome/disease] will develop, leading to true blindness.”(7) In several studies, upon the administering of proper amounts of Vitamin A, night vision loss was corrected: 1) “Initially all three subjects had no measurable rod function and delayed cone adaptation…Oral supplementation with vitamin A restored visual function to normal within 8 days in all subjects.” (8) 2) “Initial testing showed significantly reduced scotopic rod responses in both eyes and decreased vitamin A levels … He had complete recovery of both his symptoms and full-field electroretinography within 5 days of starting intramuscular vitamin A.” (9) 3) “After 3 days of vitamin A supplementation, scotopic ERG responses had already improved to one third of normal. Subjectively, the patient reported a “sudden visual recovery” 3 days after initiation of therapy. After 5 days of therapy the EOG Lp/Dt ratio returned to near normal.” (10) The retina is continuously being exposed to UV light and other stressors, so rod and cone cells have a high degree of metabolic activity as rhodopsin is continuously being depleted. Too much depletion of Vitamin A and its derivatives can lead to dry eye disease, a condition which can cause permanent damage (11,12). In addition to being ESSENTIAL for healthy¬¬ vision, adequate levels of Vitamin A/retinol are required for many important functions in the body. Retinol metabolizes into a number of derivatives referred to as retinoids. According to a research paper entitled “Vitamin A Metabolism, an update”: “Retinoids are required for maintaining many essential physiological processes in the body, including normal growth and development, normal vision, a healthy immune system, normal reproduction, and healthy skin and barrier functions. In excess of 500 genes are thought to be regulated by retinoic acid.” (13) Weston Price and the Rescued Prospector In his book Nutrition and Physical Degeneration, Dr. Price recounts the astonishing story of two prospectors his party had rescued late in the season before the fall freeze. The prospectors’ chartered plane had previously made a forced landing in the Arctic wilderness, and they subsequently decided to abandon their prospecting plan and travel by foot across a great distance back to a location where they might be picked up. Crossing the great plateau, however, one of the prospectors “nearly went blind with so violent a pain in his eyes that he feared he would go insane. It was not snow blindness, for they were equipped with glasses. It was xerophthalmia, due to lack of Vitamin A.” The prospector was incredibly fortunate, because not long after, an old Indian found him while he was sitting in the woods hopelessly holding his head. Upon examining the prospector’s eyes, the Indian led him to a nearby stream and trapped some trout. He then instructed the prospector to “eat the flesh of the head and the tissues [in] back of the eyes, including the eyes, with the result that in a few hours his [the prospector’s] pain had largely subsided. In one day his sight was rapidly returning, and in two days his eyes were nearly normal. He told me [Weston Price] with profound emotion and gratitude that that Indian had certainly saved his life.” This story conveys an important point mentioned earlier. In addition to Nyctalopia, xerophthalmia, or dry eye disease, is a very serious condition and is conclusively linked with Vitamin A deficiency (12, 13). Also, Vitamin A is an essential part of vision metabolism and is continually being “used up” just like the calories we burn to create energy. In Chapter 4, we’ll further discuss how bright-light conditions such as snow glare can intensify this process.