Night Blindness (Nyctalopia): Causes, Symptoms, Treatment

Night blindness or nyctalopia is the common name for a symptom of an underlying disease usually characterized by difficulty seeing in dark environments or at night.

It means you are not able to see as well at night, not it means you are blind altogether.

Night blindness can be caused by many different factors and it’s important to make an accurate diagnosis of the cause before you start treatment.

Among many different types of night blindness, some are treatable. If you have it, get your eyes checked by an optometrist or ophthalmologist. Once they figure out what the cause is, they may be able to offer a solution to your problem.

What Is Night Blindness?

Night blindness is when a person’s eyesight worsens in dimly illuminated areas such as restaurants, or movie theaters. Those with a night-blindness might have a harder time in transitions from a well-illuminated environment to a poorly lit environment than those without this specific vision impairment.

Night blindness is not a disease itself, but rather the symptom of an underlying eye problem, usually related to the problem of the retina. It’s not uncommon for people who are nearsighted to have problems with nighttime vision. It’s because of optical issues, not a retinal disease, though.

The cells of the retina that allow you to see in dim light are called rods. Certain diseases or conditions affect these cells, disrupting your ability to see at night.

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Symptoms of Nyctalopia

Night blindness is a common symptom of an underlying eye disorder that makes it difficult to see under dim lighting. For instance, nyctalopia often prevents people from seeing very well at night or in poorly lit areas such as hallways and staircases.

While night blindness affects many people, it may come with a number of symptoms including:

  • Headache
  • Eye pain, eye strain while focusing on objects at night
  • Eye deviation to see clearly at dark
  • Nausea and vomiting 
  • Blurry or cloudy vision at night
  • Halos or glare around lights at night
  • Increased light sensitivity

Reduced vision in adults can lead to all sorts of issues, from isolation to stress. It can also cause other health issues.

Identifying night blindness is possible by answering the following questions suggested by the American Academy of Ophthalmology.

  • Is it challenging for you to move around inside the house in poorly-lit condition?
  • Are you facing trouble driving at night due to poor vision?
  • Is it hard for you to recognize face of a person in dimly-illuminated area?
  • Is it taking too long for you to adjust with the dark room after entering from bright outside?
  • Does it take a long time to adapt with the light environment when you transition from the dark environment?

What Happens to the Eye in Dark?

The eyes are constantly adjusting to light while you’re awake, with the iris opening and closing their aperture to let in more or less light.

This is a process that happens at a rate of about one adjustment per second and it usually takes less than a minute to adjust to any given environment.

The light then passes through the retina’s rod and cone cells While cone cells process light to see color, rod cells help you see in the dark. When those rods are not working well for whatever reason, it affects your ability to see in the dark.

Night Vision Versus Daytime Vision

During the day, our eyes can gather much more light than when it is dark outside. Our brain recognizes colors better in the daytime because there is more available light.

Here are a few fascinating things about how your eyes work in the dark:

  • Eyes have limited vision at night and are mainly capable of seeing similar colors, such as black, white and grey.;
  • Eyes have low levels of visual clarity in the dark
  • There is a part of your central field of vision that isn’t as clear in the dark
  • Moving objects tend to be easier to see in low-light conditions than stationary objects.

Blindness Versus Night Blindness

Night blindness and blindness are similar in that they both refer to a loss of vision. Blindness may be more severe than night blindness, suggesting a level of visual impairment which cannot be overcome by the use of eyewear or surgery.

People who are classified as night blind can have a partial loss of vision, but it’s usually not complete. They can see clearly as a normal person during the daytime and in a well-illuminated environment.

Blindness can be caused by many different health issues, but some of the most common ones include

  • Corneal scars and opacities
  • Endophthalmitis or severe infection of internal eye structures
  • Vascular diseases that affect the blood supply of the retina
  • Systemic diseases that affect the retina in severe manner, like diabetes, hypertension
  • Optic nerve damage due to any reasons, such as end-stage glaucoma, optic neuritis
  • Complete retinal detachment, severe macular degenerations, among many others

In the United States, it’s expected that by 2050, there’ll be 8 million people with visual impairment or blindness.

Potential Causes of Night Blindness

Night blindness can be caused by several different conditions and many of them are treatable. Some systemic and eye conditions that lead to night blindness include:

Vitamin A Deficiency

Also known as retinol, vitamin A is an essential nutrient because it helps the retina absorb light. A deficiency can cause night blindness and lead to other eye problems.

Retinitis Pigmentosa

Retinitis pigmentosa is a group of rare eye diseases that result in difficulties seeing in low light and night blindness. It is a genetic disorder that usually progresses until it causes complete blindness.

Nearsightedness (Myopia)

Myopia or nearsightedness is a type of refractive error in which the eye becomes too long and cannot focus light, leading to blurry vision. People with myopia are unable to see objects in the distance accurately.

Glaucoma

A glaucoma is a group of eye conditions where the optic nerve, which connects the eye to the brain, gradually loses its ability to function. This may lead to a gradual impairment in vision and can eventually cause permanent loss of sight. Glaucoma can develop at any age but is most common in people over 60.

Anti-Glaucoma Medicines that Constrict the Pupil

Drugs that constrict the pupil can cause temporary night blindness, as even in a dark room your pupil would still be small and not as open to receiving more light.

Cataract

Cataracts are a type of eye disorder that is characterized by the clouding and yellowing of the lens. In most cases, cataracts are caused by aging when proteins in the lens break down. Cataracts can also be caused by injury or radiation exposure. When the lens is severely damaged, it becomes less transparent and light cannot pass through it properly. This causes blurry vision in dim light or night blindness.

Usher Syndrome

Usher Syndrome is a rare genetic disorder that has been reported to cause hearing loss, retinitis pigmentosa, and balance issues. It is often characterized by night blindness.

Keratoconus

Keratoconus is a disease that affects the cornea, which is the clear, dome-shaped structure on the front of the eye. The cornea’s shape becomes very steeply curved and the surface may thin or become scarred. People with keratoconus often have blurred vision and their vision may change over time.

Diabetes

With diabetes, your body either doesn’t make enough insulin or can’t use its own insulin as well as it should. Too much sugar in the blood can cause health problems such as heart attacks and strokes, kidney disease, and blindness.

Congenital Stationary Night Blindness

Congenital stationary night blindness (CSNB) is a rare non-progressive retinal disorder. This condition often makes it difficult for people to adapt to low light situations due to impaired photoreceptor transmission. Patients who suffer from CSNB may also have reduced visual acuity, myopia, nystagmus, and strabismus

If you are being treated for any of these conditions, if you start to develop symptoms of night blindness or find that the symptoms have worsened, speak to your doctor as soon as possible.

Diagnosis of Night Blindness or Nyctalopia

Your eye doctor can diagnose night blindness by evaluating your medical history and performing a standard eye examination.

The doctor usually asks you to take some blood tests to check if your levels of vitamin A and glucose are balanced, which are the contributing factors for night blindness.

Once an eye doctor has identified the cause of night blindness, it may be possible to initiate treatment based on the cause of it.

Treatment of Night Blindness

The treatment for nyctalopia depends on the underlying cause when someone has night blindness. Some cases can be treated with a simple solution like a new pair of glasses, while others may need an invasive surgical procedure, and some causes do not have treatment at all.

If you have myopia and consequently spend a significant amount of time at night in dim light, then you may be experiencing night blindness. However, this can be treated by updating your glasses prescription.

Vision should be checked regularly, every year or so, to maintain the required eyeglass or lens prescription and to detect other potential vision problems.

People with diabetes should monitor their blood glucose levels and take the advice of their doctor when it comes to treatment. This can help with night blindness.

If you think a vitamin A deficiency is the reason for your night blindness, try adjusting your diet or taking supplements to provide more of the nutrient.

Food items like carrots, eggs, collard greens, sweet potatoes, and many others can be found to contain Vitamin A or Beta-Carotene.

The treatment of cataracts and glaucoma, either through medicines or surgery, depends on the case. The right treatment can provide relief for symptoms like night blindness.

There is no or little hope for the treatment of nigh blindness if the condition is caused by a genetic disorder such as retinitis pigmentosa.

Contact an eye doctor if you have a hard time seeing in poorly lit environments or when driving at night.

The cause for night blindness is different for each person, so it’s best to consult with an eye doctor to effectively manage the symptom.

Preventive Measures

You can’t change your genetic predisposition, but you can do some things to help you stay healthy if it turns out that night blindness is caused by a poor lifestyle.

Vitamin A is a key nutrient that can help prevent night blindness. It works by providing a healthy immune system and maintaining your retinal health and eye health. Foods rich in vitamin A include carrots, sweet potatoes, squash, apples, oranges, spinach, and kale.

Sunglasses do a lot more than just protect your eyes from the sun. They also protect against cataracts, macular degeneration, and glaucoma caused by UV rays. Make sure that any sunglass you buy block out 99% of UVA and UVB rays, cover the widest range possible of angles, and filter more than 90 percent of visible blue light.

Exercise is one of the most important factors in a healthy lifestyle. It is essential to maintain a healthy weight and manage blood sugar levels. Exercise may not only reduce your risk of heart disease, type 2 diabetes, and some cancers, but it can also have positive effects on your vision.

When to See a Doctor?

If you find it difficult to drive at night – or if you can’t see at all, or bumping and tripping through your darkened house, it’s possible that you suffer from night blindness.

To confirm the condition and severity of the night blindness, meet with your healthcare provider. Night blindness is a symptom of some serious illnesses that need to be diagnosed and treated as soon as possible.

Takeaway

If you experience problems of night blindness, make sure to take precautions so that you are safe at night and don’t put others in danger.

Night blindness can sometimes lead to accidents. Until your eye doctor figure out what’s causing it and, if possible, treat the condition, avoid driving at night as much as possible.

Arrange to drive a vehicle during the day or find a ride from somebody else if it is necessary to go somewhere at night.

You can protect your eyes from glare by wearing sunglasses or a brimmed hat. These pieces help filter light and reduce the eye strain that often comes with a high-glare environment, which can make the transition into darker places a lot easier.