When it becomes harder to see at night or in an environment with low light, the condition is called nyctalopia, or night blindness. One common concern for people with night blindness is safety when driving at night.
The portion of the eye that recognizes light is called the retina. The retina lines the inside of the back of the eye and is filled with light receptors called cones and rods. Cones help the eye see in color while rods see black and white images. Rods also do most of the work of seeing when we are in an environment with low light. Night blindness occurs when something damages the rods.
Causes of Night Blindness
Some people are born with night blindness, but for the majority of people, night blindness develops over time and is often associated with the aging process. Causes of night blindness include:
• Birth defects
• Low Vitamin A – This vitamin acts as an antioxidant and is known to be important in producing pigments in the eye. Low levels of Vitamin A in the body can lead to night blindness and other vision problems. Appropriate levels of Vitamin A can help prevent night blindness and may also help prevent cataracts and macular degeneration.
• Cataracts – This clouding of the cornea of the eye reduces vision and is a leading cause of night blindness.
• Degeneration of the retina – Retinitis pigmentosa is one example of an eye disease where damage occurs to the retina. This type of problem tends to get worse as we get older.
• Use of certain drugs - Symptoms of night blindness may come on gradually and initially be difficult to detect. Patients may first notice that it seems to take the eyes longer to adjust when looking from a well lit area to a darker area. This can become a serious hazard when driving at night because it may take the eyes several seconds to adjust after the bright lights of an on-coming car have passed by.
Risk Factors for Night Blindness
You may be at higher risk to develop nyctalopia if you have one or more of these risk factors: