Some individuals can see perfectly well when there is a decent amount of light. But once the light starts to dim and fade away, their vision becomes poor. These individuals suffer from a condition called “nyctalopia,” more commonly called “night blindness.”
It’s a bit of a misnomer, as there is no blindness involved; nobody with this condition is truly blind. It is a matter, instead, of having impaired eyesight in the dark. The symptoms include difficulty seeing when you are driving during the evening or nighttime, vision that becomes noticeably worse in reduced light, and your eyes taking longer to adjust to the dark.
The problem is in your retina, the middle of your pupils. Theretina contain photoreceptors that are responsible for making the necessary adjustments when there is more light or less light, bright light, or darkness. These photoreceptors come in the shape of either a cone or a rod. Cones are in the center of the retina, focusing on fine details and color. Rods line the edges of the retina, and do most of the work when light is dim.
Therefore, it’s these light-sensitive rods that are the issue with night blindness. The rods contain a purple pigment called “rhodopsin.” Here’s where the vitamin deficiency comes in… Rhodopsin adjusts to darkness only when there is a sufficient supply of vitamin A in the body. When there’s enough vitamin A, you can see objects in dim light. And there it is: the hidden cause of night blindness could be not having enough of this vital nutrient in your body.
In the early 1900s, researchers identified vitamin A as being the crucial element in night blindness. As a matter of fact, vitamin A is also known as “retinol,” because it creates the pigments in your retina. Good vision depends largely on this nutrient. When there is a severe vitamin A deficiency, your cornea can actually soften, become very dry, or even begin to dissolve.
The nutrient is responsible for transmitting light that enters your eye in to nerve signals. Thus, it helps you understand what is in front of you by turning light into pictures. Vitamin A makes sure the retina functions properly, particularly when adjusting your vision from a place with bright light to a place of darkness.
Indonesians, for example, are notoriously vitamin A deficient. They call this inability to see in the night “chicken eyes,” because the birds cannot see in the dark. As a side note, eye drops of vitamin A are available to treat a case of dry eyes, caused by disruptive tear glands that don’t secrete enough tears.
Now, treating vitamin A deficiency will help restore your vision in the night. It can be obtained orally or
intravenously; however, high doses of vitamin A can be dangerous, so only take it with a doctor’s recommendation.
You can prevent night blindness by obtaining enough vitamin A through your diet.
Vitamin A is found in many milk products, including cheese, butter, fortified margarine, and cream. It’s also
found in liver, cod liver oil, and the yolks of eggs. Vitamin A is often fortified, because in low-fat dairy products (skim milk, etc.), it is mostly lost when the fat is removed. Look for low-fat dairy options “fortified” with the vitamin. Many breakfast cereals are also fortified in this way — check the label. In all of these sources, vitamin A is known as retinol.
Now, obviously something should spring to mind when you read the food sources of vitamin A. Many of them are not particularly healthy to be eating on a daily or regular basis — for instance, egg yolks, liver, and butter.
So, where else can you find vitamin A? The answer is: any foods that are high in beta-carotene. Your body has the ability to convert beta-carotene into vitamin A. Finding beta-carotene in the diet is a very healthy way to get vitamin A. These foods include broccoli, dark green leafy vegetables, and any fruits or vegetables that are orange or yellow.