Night blindness symptoms, causes and treatment

What is night blindness (nyctalopia)?

Night blindness, also known as nyctalopia, is a condition which means that your eyes are unable to adapt to low-light conditions. It usually occurs when there are issues with the rod cells – a type of photoreceptor cell in your retina – which are responsible for facilitating your night vision. We’re going to look into the symptoms of night blindness, the various causes of it, and how it can be treated and prevented in the future.

How do we see in the dark?

The retina, which is at the back of your eye, is responsible for your night vision. It is made up of photoreceptor cells called rod cells and cone cells. The rods facilitate your night vision, while the cones help your vision adapt to bright light. These cells react to various levels of light, for instance when you switch the light on in the room, or when you enter a dim environment after having been outside in bright light.

Your photoreceptor cells need to react to different light levels to ensure that you can see properly in various environments. This is why your pupils are constantly changing size, in order to accommodate different levels of light. In darker places, your photoreceptor cells send the signal for your pupils to expand and let more light in, helping you to see better. When it’s light, the photoreceptor cells send the signal for your pupils to constrict and reduce the amount of light entering your eyes, in order to protect your vision from bright light.

If any diseases, injuries or eye conditions begin to affect your photoreceptor cells, your night vision will be impacted too.

Symptoms of night blindness

There are a number of signs that indicate night blindness, but the main one that people notice tends to be when they struggle to see in a dim room, such as in the evening or when waking up during the night. You might also find that you:

• Struggle to drive at night
• Can’t recognise faces in low light
• Take a while to adjust when moving from dark to bright light
• Can’t see stars in the sky

There are several other symptoms that could suggest underlying conditions that lead to night blindness, including:

• Eye pain
• Headaches
• Vomiting
• Nausea
• Light sensitivity
• Blurred vision
• Cloudy vision

If you experience any of these symptoms along with worsening vision in dark environments, speak to your optician about night blindness and any potential treatment you may require.

What causes night blindness?

There are a number of causes of night blindness, some of which are simple to change (such as dietary reasons), while others are more severe and are irreversible. Conditions and diseases which are known to lead to night blindness include:

• Nearsightedness (myopia)
• Cataracts
• Vitamin A deficiency
• Glaucoma and glaucoma medications
• Retinitis pigmentosa
• Diabetes
• Keratoconus
• Usher Syndrome

The exact treatment for your night blindness depends on what is causing it. This can be determined by your optometrist with eye tests to assess the health and status of your eye. Regular eye tests are crucial in monitoring your eye health, whether or not you have night blindness. Conditions are often picked up at routine eye tests as the back of your eye can indicate so many eye conditions and other issues, such as diabetes, high blood pressure, glaucoma and more.

How to treat night blindness

Can night blindness be cured?

Most of the time, the treatment for night blindness is relatively straightforward, however the method depends the exact cause of it. As night blindness can occur for a number of reasons, you must determine the root cause of your night blindness before you can receive the appropriate treatment. A visit to your optician for an eye test should reveal the cause of your night blindness, thereby also revealing which treatment course you require.

New prescription

Being severely short-sighted (myopic) can be a cause of night blindness. Myopia occurs when your eye has  grown too long, preventing your retina from focusing light properly. People with myopia can sometimes struggle to see more than a few feet in front of them, and if you’re myopic but aren’t wearing glasses or contact lenses with the right prescription, you may find that you experience even more difficulties. Sometimes, new glasses are what you need to correct your night blindness.

Cataract surgery

Night blindness can sometimes occur due to the primary eye condition cataracts. Cataracts form when the eye’s natural lens becomes cloudy and hardens with age. The clouded lens limits the amount of light that the eye receives, causing particular visual issues in dim light. The good news, however, is that cataracts can be treated with one of the simplest eye surgeries in the world. The eye’s natural clouded lens is replaced with an artificial lens which restores good vision and eliminates night blindness.

More vitamin A

Some cases of night blindness are caused by a lack of vitamin A in your diet. This is because vitamin A makes up a protein which absorbs light in your retina and an absence of it can lead to vitamin A deficiencies and retinal dysfunction.

Foods which are rich in vitamin A are:

• Orange and yellow fruits and vegetables (e.g. melon, carrots, sweet potatoes, pumpkins, mangoes)
• Milk
• Leafy greens e.g. spinach
• Eggs
• Cod liver oil

You can read about other foods which boost your eye health on our blog here. Ensuring you eat a balanced diet with enough vitamin A could be what you need to reduce your night blindness symptoms.

New glaucoma medication

Glaucoma is a condition in which the fluid from your eye can’t drain properly, meaning it remains in your eye and leads to a build-up in eye pressure. This increase in eye pressure causes your peripheral vision to gradually worsen, eventually leading to total blindness in severe cases. Glaucoma medication is taken in order to lower your eye pressure and help the fluid drain from your eye. However, some glaucoma medications can cause the pupil to close, thereby preventing light from entering the eye and leading to night blindness.

Living with night blindness

If you have been diagnosed with night blindness and are still suffering with the symptoms, you should, above all, refrain from driving at night. This can be very unsafe as your eyes fail to adapt quickly enough to oncoming headlights or streetlamps, impeding your vision. It goes without saying that when you’re in charge of a vehicle travelling at speed, good vision is of the utmost importance.

You should also aim to exercise regularly to keep your eye pressure as low as possible, and try to eat a balanced diet to ensure you’re getting enough vitamin A. The outlook for most forms of night blindness is good with treatments available to improve your vision. You may also find that sunglasses help to reduce your symptoms in day to day life, particularly when entering brightly lit environments that your eyes would struggle to adapt to.

Attend regular eye tests and do not hesitate to seek medical advice if you notice that something has changed – acting quickly can help to preserve your vision and allow you to have effective treatment administered as soon as possible.