Definition

Night blindness is difficulty seeing in the dark or in low light. One of the most common issues with night blindness is difficulty driving in the evening or at night.

The Retina of the Eye

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Causes

Night blindness is caused by disorders or conditions that affect the cells in the retina that are responsible for vision in dim light (cones). Examples include:

• Cataracts, which are cloudy areas in the lens of the eye
• Some forms of retinal degeneration, such as retinitis pigmentosa
• Posterior uveitis
• Open-Angle Glaucoma
• Vitamin A deficiency
• Birth defects affecting the retina

Risk Factors

Age is the most common factor that contributes to night blindness. Many eye conditions develop as people get older. Other factors that may increase the chance of night blindness include:

• Common vision disorders, such as difficulty seeing or focusing on distant objects (nearsightedness)
• History of eye disorders, such as cataracts, glaucoma, or keratoconus
• Family history of eye disorders
• Diabetes (contributes to eye disorders)
• Medication for glaucoma that constricts (narrows) the pupil
• Genetic mutations that contribute to eye disorders
• Not getting adequate amounts of vitamin A, which come from green leafy vegetables, eggs, and whole milk products. Vitamin A deficiency is rare in the United States, but still occurs in certain less developed countries.
• Disorders that affect the ability of the body to absorb vitamin A:
  • Liver or pancreatic disorders
  • Intestinal conditions
  • Gastric bypass surgery for obesity

Symptoms

Symptoms are difficulty or inability to see in low light or darkness, even with glasses or contact lenses. While driving, this may also occur a few seconds after the bright headlights of an oncoming car have passed.

Trouble adjusting from low levels of light to high levels of light

Diagnosis

You will be asked about your symptoms and medical history. A complete eye exam will be done. A blood test can be used to test the amount of vitamin A in your blood.

Treatment

Treatment depends on the cause of night blindness. Options may include:

• Taking vitamin A supplements
• Having cataracts removed
• Taking medications to treat eye conditions
• Using low-vision aids and making lifestyle adjustments

Night blindness may require taking extra safety precautions when necessary. This may mean avoiding driving in the evening or at night.

Prevention

To help reduce your chance of night blindness:

• Follow treatment plans for chronic conditions that may contribute to night blindness
• Have regular eye exams as advised by your eye doctor
• Eating a diet with adequate amounts of vitamin A