Fall and Winter may have less daylight, but our activities don’t stop at sundown. At night, color detection capabilities and overall visual acuity decreases. This is because humans use two different types of cells, one for day/bright light vision, and one for night vision.
In daylight, our eyes use cone cells that allow us to detect different colors and form a sharp image of objects. In darkness, however, our eyes are more dependent on rod cells. Rods function in much dimmer light, but can’t detect the different wavelengths of light (or colors) And, the overall picture rods generate is far less sharp or detailed. Cone cells are much more concentrated in the center of the retina, and rod cells are more concentrated around the edge of the retina.
9 Facts About Night Vision
- Humans require about 15-30 minutes for dark vision adaptation. This is because rods are dependent on the photopigment rhodopsin to function. Light breaks down rhodopsin. However, when walking into a dark space, rhodopsin will regenerate and vision will begin to improve. Dark adaptation takes about 15–30 minutes, and, when complete, increases light sensitivity by about 100,000 times.
- One of the first signs of cataracts may be poor night vision, including halos around lighted objects. This is because cataracts distort the light entering the eyes.
- Myopia, or nearsightedness, may also lead to blurry vision at night. Glasses or corrective lenses will help if myopia is the cause of poor night vision.
- Prolonged exposure to sunlight is a risk for cataract development and poor night vision. Always wear sun glasses during the day to protect your eyes
- Night vision problems can be the result of Vitamin A deficiency. Problems seeing at night may be one the first symptoms that a patient is suffering from Vitamin A deficiency. A lack of vitamin A causes the cornea to become very dry, leading to clouding of the front of the eye, and night vision loss. In addition to not ingesting enough Vitamin A, some liver conditions may also lead to Vitamin A deficiency.
- Certain medications may also lead to poor night vision. Accutane, for example, is a medication used to treat acne, may lead to night vision problems.
- Zinc deficiency may also cause poor night vision. This is because zinc is necessary for Vitamin A to be activated and used by the eyes.
- Uncontrolled diabetes damages blood vessels in the eyes, and throughout the body. Damage to eye vessels begins in areas surrounding the retina where rods are located, which can lead to worsening of vision. Ultimately blood vessel damage may effect the cones as well, leading to decreased visual abilities during the day as well.
- Retinitis Pigmentosa is a rare genetic disorder characterized by degradation of the retina One of the first symptoms of Retinitis Pigmentosa may be a decline in night vision
If you have noticed worsening night vision, Dr. Rocha and his team can help. An eye exam is typically the first step in determining potential causes of night vision problems. Call 201.489.8868 to schedule an exam.