Night blindness, also called nyctalopia or nyctanopia, is a medical condition that affects a person’s vision, particularly at night or in an area with little to no light. In addition to having difficulty seeing at night, a person with this condition may have difficulty seeing when moving from a brightly lit area to one that is dimly lit. As a result, these individuals generally experience difficulty driving at night or in the evening.
The underlying cause of night blindness is usually a problem with the retina. This is because the retina is made of rods and cones, and the rods help the eye see in areas with poor lighting. There are several medical conditions that can cause problems with the retina and lead to problems with vision in low light.
One common cause is cataracts, which are opaque or cloudy areas in the eye’s lens. This is more common in individuals over 50 years of age. In a younger person, night blindness can often be the first sign of retinitis pigmentosa. This eye disease, which has a genetic link, causes the retina to become damaged and progressively worsens over time.
A person with myopia, or nearsightedness, may also experience night blindness. With myopia, the person has difficulty focusing his or her eyes. As a result, far away objects appear blurry, and the person may also have difficulty adapting to darkness.
Poor nutrition, specifically a deficiency in vitamin A, can also cause problems seeing at night. Vitamin A is responsible for keeping the skin and skeletal tissue healthy. In addition, it encourages good vision, particularly in areas that are not well lit. Vitamin A is found in whole milk, animal liver, and some foods that have been fortified. Supplements are also available to ensure a person receives enough to prevent night blindness.
Certain drugs can also cause night blindness, particularly those that block the body’s ability to absorb vitamin A. Some types of birth defects can also cause deformities in the retina and lead to this condition.
Depending on the underlying cause of the disorder, it can be treatable. Cataract removal, for example, can improve the condition. In some cases, prescription glasses can be beneficial as well.