What is night blindness and what are the risks?

14 January 2020

Author: Kate Green

night blindness

What is night blindness?


Night blindness, also known as nyctalopia, is a condition which means your eyes are unable to adapt to low-light conditions. This means that simple everyday activities, such as driving in the dark or popping to the bathroom during the night, become a lot more difficult. The back of your eye – the retina – has different types of photoreceptor cells to help you see. These are called rods and cones: rods are responsible for facilitating your night vision, while cones help your vision in bright light. Night blindness usually occurs as a result of issues with your rod cells, although there are actually a number of causes of night blindness.


How do I know if I have night blindness?


We all find it a bit trickier to see in the low light than we do in daylight, so how do you know if what you’re experiencing is normal, or if you’re suffering with night blindness? Nyctalopia can actually prevent you from seeing stars in the sky and, in severe cases, from spotting obstacles in a dark room. Signs that you have night blindness could be having difficulty in recognising faces in dim light and struggling to see road signs in the dark. One of the key symptoms, however, is if your eyes take an abnormally long time to adjust to brightness after having been in the dark. This is because your photoreceptor cells aren’t reacting quickly enough to the visual changes, potentially putting you at risk when it comes to hazards you can’t see.


As night blindness can be caused by a number of other primary conditions, symptoms vary. However, you should look out for and take notice of:

  • headaches
  • eye pain
  • nausea
  • vomiting
  • blurry or cloudy vision
  • sensitivity to light
  • difficulty seeing into the distance


It is important to seek medical advice if you begin experiencing any of the above symptoms.


What causes night blindness?


Night blindness has a number of causes, usually occurring as a result of a pre-existing condition which affects the retina – but not always. Glaucoma is a condition where your eye pressure is too high, leading to reduced peripheral vision and – if left untreated – can leave you completely blind. The medication that people take to treat glaucoma usually works by constricting the pupil, allowing even less light into the eye and making them especially susceptible to night blindness. In this case, the photoreceptor cells in the retina are unaffected, but night vision is still impaired.


Night blindness can also occur as a result of cataracts as a primary eye condition. Cataracts occur 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. Thankfully, cataracts can be treated easily by replacing the eye’s natural clouded lens with a clear artificial one, restoring good vision and eliminating night blindness.


Unsurprisingly, being severely short-sighted can contribute to night blindness. Also known as myopia, this is a relatively common visual issue where people struggle to see objects in the distance clearly. It occurs when the eye grows too long, preventing the retina from focusing light properly. As people who are short-sighted struggle to see clearly more than a few feet in front, having darkness limit their visual field even further can make things very difficult.


People with vitamin A deficiency often suffer with night blindness. Vitamin A is needed for eye health and is essential for helping you process images. It plays a role in transforming nerve impulses into images in the retina, which is how you see anything at all. Without vitamin A, your eyes struggle to complete this process, with night vision being one of the first things to go. Thankfully, this can often be easily remedied simply by eating more foods with vitamin A in them. This includes orange coloured foods like carrots, pumpkins and sweet potatoes, as well other foods such as spinach, milk and eggs.


One of the final causes of night blindness is an eye disease called retinitis pigmentosa. Simply put, this condition causes the breakdown and loss of retinal cells, eventually leading to blindness. When the rod cells in the retina are lost, night vision is negatively impacted. Sadly, this condition is inherited and there isn’t a cure yet. Dark pigment cells collect in your retina, creating tunnel vision to begin with, making it harder to see in dim lighting, before all vision is gradually lost over time.


How can I reduce my symptoms?


Tackling the symptoms of night blindness will depend on the underlying cause of your particular form of night blindness. You can try making the following changes to help with the symptoms of the condition:


How can night blindness be treated?


Night blindness isn’t always treatable. Obviously, if your night blindness is related to vitamin A deficiency, then changing your diet to include more of those foods will help. Likewise, having surgery to remove cataracts or to release pressure occurring as a result of glaucoma will also have positive effects on your night blindness symptoms. However, retinitis pigmentosa has no treatment available at this stage. This is because it’s a genetic condition and remains unaffected by vision correction lenses or retinal surgery.


As Healthline succinctly says, “You can’t prevent night blindness that’s the result of birth defects or genetic conditions. You can, however, properly monitor your blood sugar levels and eat a balanced diet to make night blindness less likely.” Monitoring your eyesight is crucial and you should take all the steps you can in order to preserve it, particularly when it comes to diet and simple lifestyle changes.

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