Ask The Expert: What is Night Blindness (Nyctalopia) & How Serious is it?

Eye Health Care

28 February 2025

Night blindness is a condition that makes it difficult for people to see clearly in low light or darkness. It can make night driving quite difficult. Glare from oncoming headlights and streetlights can magnify night blindness symptoms, making sufferers nervous when driving.

At Optegra, our vision experts are here to help. We’ll debunk common myths about the conditions and share night driving symptoms to be aware of – helping keep you safe behind the wheel.

What is Night Blindness?

Night blindness (nyctalopia) isn’t a disease but rather a symptom of underlying eye conditions. People with night blindness have difficulty seeing in low-light or nighttime environments, making driving or walking through dark areas quite difficult. They may also experience impaired vision when transitioning from bright to dim lighting, as their eyes struggle to adjust effectively.

Can Night Blindness Develop in Children?

Children can experience night blindness, especially via genetic conditions such as retinitis pigmentosa or vitamin A deficiency.

Parents should address their child’s night blindness based on its underlying cause.

If vitamin A deficiency is the cause, treatment options include:

Increasing dietary intake of vitamin A-rich foods such as dairy products, leafy green vegetables, and oily fish
Administering vitamin A supplements under medical supervision

For genetic conditions like retinitis pigmentosa:

No cure is currently available, but management strategies can help

Consult with an eye doctor to discuss coping mechanisms and ways to improve quality of life

General management strategies include:

Use intensity-adjustable night lights to increase confidence and improve sleep
Provide a flashlight for use in low-light conditions
Draw curtains before dusk to minimize fear of darkness outside
Ensure regular eye check-ups to monitor the condition and adjust treatments as needed

Parents should consult with an eye care specialist to determine the specific cause of their child’s night blindness and develop an appropriate treatment plan. Early intervention is crucial, especially in cases of vitamin A deficiency, which can lead to more severe vision problems if left untreated

How Do We See in the Dark?

For us to be able to see in the dark, many eye structures work together to maximise low light sensitivity to low light:

Cornea – the clear, curved front surface of the eye focuses light as it enters the eye. This helps the maximum available light to reach the retina and is especially important in low levels of light.

Pupil – this is the black opening in the centre of the eye. It controls how much light enters. When light conditions are dark, the iris (the coloured part of the eye) relaxes which dilates the pupil, making it larger. This acts to allow more light to enter the eye, which enhances sensitivity to dim environments.

Lens – The lens provides further focus on the light that reaches the retina at the back of the eye. In darkness, the lens adjusts so lower light levels are concentrated for clear vision.

Retina – This light-sensitive layer at the back of the eye is made up of two types of photoreceptor cells – rods and cones. Rods are sensitive to light and are important for seeing in the dark. Cones detect colour and work best in brighter light. When it is dark, rods take over. They take time to do this (20–30 minutes) to fully adapt, a process known as dark adaptation.

Optic Nerve – This nerve transmits signals from the rods and cones to the brain.

What Causes Night Blindness (Nyctalopia)?

Night blindness is a symptom caused by many different conditions and factors affecting the eye’s ability to see optimally in low light.

Addressing night blindness can only be done by identifying and treating the responsible underlying condition.

Cataracts

Cataracts are a clouding of the lens that for due to aging, injury, or other factors.

Cataracts scatter incoming light, and this reduces the light reaching the eye. This effect can be magnified in dark environments, where the ability to distinguish subtle contrasts is already challenged. Cataract surgery is often required to correct these changes.

Glaucoma and Night Blindness

Glaucoma causes damage to the optic nerve, this is condition has multi-factorial causes but most commonly arises from raised intraocular pressure.

Glaucoma affects peripheral vision and can have a negative impact on light sensitivity, which makes it harder to see in dark environments. In turn, certain glaucoma medications called miotics can also result in reduced night vision. Learn how glaucoma can affect your driving, specifically at night.

Diabetic Retinopathy

Diabetic retinopathy arises from damage to the retina’s blood vessels. The cause is usually poorly controlled diabetes . It reduces the retina’s ability to respond to light – causing problems with night vision.

Keratoconus

Keratoconus (where the cornea thins and bulges into a cone shape) is linked to night blindness. The irregular shape of the cornea makes light scatter, and this causes visual distortions like glares and halos. These happen more frequently in low-light conditions, where the eye relies on clear light focusing for contrast sensitivity.

The Symptoms of Night Blindness

Night blindness can cause various issues from seeing obstacles in the room to driving at night. The nature of the symptoms can depend on the underlying eye condition:

Difficulty seeing in low-light conditions
Increased reliance on bright light
Glare sensitivity
Discomfort due to glare from headlights and streetlights
Slow adaptation to darkness
Reduced peripheral vision in dark environments

Treating Night Vision (Nyctalopia)

If you experience Nyctalopia, consider first undergoing a night vision test. This will evaluate how well your eyes adjust to dark conditions and identify possible underlying issues.

Once the underlying conditions are identified; they need to be addressed. This will vary depending on the type of condition (for example cataract surgery if a cataract is identified).