You may be finding that increasingly your eyes are having trouble adjusting in dim light, or at night. Whilst naturally as humans we can’t see as well at night, a healthy eye can adapt to the darkness.
What is night blindness?
During our day, our eyes are constantly changing and adjusting to different levels of light. When we enter into a darker area, the pupil in our eyes will get bigger allowing more light to enter into the eye. At the back of your eye is the retina that receives this light. The retina is made up of photoreceptors, rod cells and cone cells, that convert the light into electrical signals that your brain interprets as images. The rod cells help you to adapt between darkness and light, while the cone cells help you to distinguish colours. Difficulty seeing at night happens when these rod cells aren’t working well. This is known as night blindness or nyctalopia.
How do I know I am suffering from night blindness?
You may not be aware that you are suffering poor vision at night because it may seem normal to you. Here are some signs that you may be suffering from nyctalopia:
- Difficulty seeing in low light. You may be finding it difficult to distinguish objects or recognise people at night. They may appear blurry. You may notice this when you try to move around a darkened room at home.
- Trouble adapting to different light levels. It is normal for your eyes to take time to adjust when you move from a light area to a darker one. You may notice that it is taking an abnormally long time for your eyes to adjust or that you can’t see anything for a short while.
- Driving at night is difficult. You may be finding it increasingly difficult to make out shapes and road signs. The fluctuations in light with street lights, periods of darkness and the headlights of oncoming cars can make it difficult for your eyes to adapt causing blurry vision, sensitivity to the glare and an inability to see clearly what is ahead, making it an anxious time for you.
- Halos around lights. You may notice rings around lights or other light sources. This can show that your eyes are having difficulty focussing and processing the light.
What causes night blindness?
We mentioned before that night blindness is caused when the rod cells in the retina are not functioning well or are damaged. So, what can cause this?
- Short-sightedness (myopia). As it is naturally more difficult for short-sighted people to see things clearly in the distance, it can also affect the ability to see clearly at night.
- Cataracts. Due to a break down of the proteins in the lens of the eye, it can become cloudy affecting light travelling through the eye to the retina causing blurry vision. Because of the need for more light to see, driving at night can cause difficulty and may be the first symptom you notice. Over-exposure to sunlight is a major risk factor for the development of cataracts so it’s important to always wear sunglasses.
- Glaucoma. Caused by damage to the optic nerve, glaucoma can result in blind spots and blurry vision that can lead to total blindness. Medications for glaucoma can also constrict the pupil making it difficult to see at night.
- Vitamin A deficiency. Vitamin A is essential for good vision. It makes up a protein that absorbs light to the retina and keeps it healthy and functioning well. A lack of vitamin A can have an impact on your vision and result in night blindness.
- Lack of Zinc. Zinc helps in vitamin A to function well, so it’s important to ensure of have enough zinc.
- Retinitis Pigmentosa. This is a genetic condition that causes deterioration of the retina making it difficult to see in low light.
- Diabetes. High blood sugar damages the blood vessels and nerves in the eye, which can lead to a condition called diabetic retinopathy. This will impact your ability to see in low light.
What should I do if I think I am suffering from night blindness?
It is important that you visit your optometrist for a full examination to check for a possible cause, as some can be serious. There are treatments available, depending on the cause. For example, cataracts can be surgically removed and replaced with an artificial lens.
What can I do to minimise the development of poor night vision?
There are things you can put into place to help keep your eyes healthy and lessen your chances of developing poor vision at night.
- Keep your prescription up-to-date
- Wear sunglasses in sunlight to protect your eyes from UV rays
- If you are diabetic, keep your blood sugar levels under control
- Maintain a healthy diet rich in antioxidants, vitamins and minerals, choosing foods that are rich in vitamin A such as carrots, sweet potatoes, pumpkins, spinach, milk and eggs.
- Maintain your regular check-ups with your optometrist so any problems can be caught early.
It is important that if you are suffering from night blindness that you take precautions to keep yourself and others safe, particularly if you are struggling with driving at night. It may be time to limit your driving to daylight hours and arrange for assistance or some other form of transport at night time.