8 Causes of Night Blindness (Nyctalopia) & Treating It

Night blindness (nyctalopia) refers to considerable difficulty seeing in poor light conditions. Night blindness is not a condition itself but rather a symptom of other types of vision conditions.

1. Vitamin A Deficiency

Night blindness can be a symptom of vitamin A deficiency. Rod cells, a sensitive type of eye cell, collect light for night vision. In vitamin A deficiency, there is reduced production of rhodopsin (the pigment needed by rods to help see in low light).

People at risk for vitamin A deficiency include those with these conditions or characteristics:

• Intestinal inflammation
• Liver and pancreas diseases
• After bariatric surgery
• Intestinal inflammation
• Liver and pancreas diseases
• Severely restricted diets
• Young children and pregnant people in low-income countries and populations of developing nations (due to malnutrition and infectious diseases)

Dietary changes, such as eating foods high in vitamin A (like leafy green vegetables, carrots, sweet potatoes, eggs, cantaloupe, and oranges), may help reverse symptoms. In some cases, supplements may be necessary but should not be taken unless a healthcare provider advises.

2. Injury

The pupil gets bigger (dilates) in low light to let in more light. The light is received by the retina, which is the tissue at the back of the eye that holds the cone cells (help people see colors), and rod cells (help with vision in low light). Damage to rod cells from injury or disease can make it difficult to see in low light.

3. Medical Conditions

Eye conditions that may affect the ability to see in low light or cause night blindness include:

• Cataracts: Cloudy areas in the lens block or distort light passing through the lens.
• Choroideremia: This genetic condition causes progressive vision loss, usually starting with night blindness.
• Dry eye: Not enough tears or poor quality tears prevent the eye from being properly lubricated, potentially damaging the eye’s surface.
• Glaucoma: High pressure in the eye causes damage to the optic nerve and blood vessels in the eye. It affects both daytime and nighttime vision, starting with peripheral vision, then moving to central vision. Medication for glaucoma can constrict the pupil.
• Ketatoconus: The cornea is very steeply curved.
• Macular degeneration: Retinal changes lead to distortion and blind spots can affect daytime and nighttime vision.
• Poorly controlled diabetes: Erratic blood sugar can affect oxygen levels in the eyes and vision, including poor night vision, floaters, and blurred vision.
• Retinitis pigmentosa (and other retinal conditions): Rod cells cluster around the edge of the retina, where damage can start. Damage to rod cells can harm low-light vision.
• Usher syndrome: This rare genetic condition causes hearing loss and vision loss due to retinitis pigmentosa.
• X-linked congenital stationary night blindness: This disorder of the retina typically causes night blindness and other vision problems.

4. Refractive Errors

Vision problems during the day can also make it difficult to see at night. This might include myopia (nearsightedness) or other refractive errors requiring glasses or contacts

5. Refractive Surgery

Refractive surgery, such as laser-assisted in situ keratomileusis (LASIK), can affect night vision, leading to problems such as:

• Difficulty seeing in low-light conditions
• Glare
• Halos around lights
• Noticeable visual disturbances when driving at night
• Starbursts around lights

Usually, these problems improve within a few weeks to months, but may be prolonged or permanent.

6. Medications

Medications can affect the eyes in a number of ways, including pupil size which determines how much light enters the eye. Some of the medications that may affect night vision include:

7. Age

Vision can decline over time due to multiple conditions that can develop with age.

Age-related changes that can affect the ability to see in low light include:

• Microscopic changes over time to the lens, leading to cloudiness
• Reduced number of rod cells
• Reduced tear production, leading to drier eyes and irritation of the cornea
• Slower reaction to changes in light
• Weakened muscles in the iris make the pupil smaller, allowing in less light
• Worsened overall vision

8. Sunlight Exposure

Sunlight exposure can contribute to visual problems such as:

What Are Symptoms of Night Blindness?

Symptoms of night blindness may include:

• Difficulty seeing stars in the sky at night
• Problems seeing objects or faces in low light
• Seeing halos or glare around lights
• Sensitivity to light
• Taking longer to adapt to lower light after being in a bright environment and brighter light after being in the dark
• Total loss of vision lasting more than a few minutes when entering a dark space
• Vision that is blurry or cloudy in low light

How an Eye Doctor Tests and Diagnoses Causes of Night Blindness

Problems with night vision can be a sign of serious eye conditions and should prompt a visit to an eye doctor for a full exam. Your provider will ask you questions, examine your eyes, and test your vision.

The Pelli-Robson Contrast Sensitivity Chart test is similar to the common letter eye chart test, but the letters are in different shades of grey to measure how well you see the contrast between the grey shapes and white paper.

The eye exam may include:

How Can You See Better at Night?

Treatment for night blindness first involves identifying and addressing any underlying causes, such as vitamin deficiencies, prescription adjustments, or medical conditions.

This may include prescriptions for corrective lenses, surgery, medication, supplements (under the advice of your healthcare provider), lifestyle changes, or other treatments depending on the issue being addressed.

Some ways to help with night blindness include:

• Adapt your night driving by dimming dashboard lights, avoiding looking directly into oncoming headlights, using well-lit streets, and keeping your windshield and headlights clean.
• Add antireflective coatings to your lenses.
• Avoid driving at night unless your eye care provider has said it is safe for you to do.
• Ensure you have good lighting throughout your home.
• Keep a flashlight or flashlight phone app close at hand.
• Keep your glasses clean and in good repair.

Key Takeaways

• Vitamin A deficiency, medical conditions, medications, injury, age, and sun damage can cause night blindness.
• Night blindness can make driving at night difficult and potentially dangerous.
• Treatment for night blindness primarily involves identifying and addressing any underlying causes.