There is a difference between being really night blind and seeing worse in the dark, says Andrea Biswane-Vergunst. She is an optometrist at the Eye Fund. “With night blindness you can see almost nothing in the dark and there is often more to it.”
Most people have symptoms of night blindness, they see worse or it takes their eyes a while to get used to the dark. It is difficult to say exactly how many people are affected by this. What is known is why one driver sees worse on a dark N-road than the other
‘Just to the optician’
This can have several causes. The most common is quite simple: people need glasses or if they already have glasses or contact lenses, a different strength. During the day they notice this less, but at night they do.
“Nine times out of ten there is nothing wrong and the strength has to be adjusted. There are a lot of people walking around with a strength of minus half who do not have glasses or lenses.” There is an easy solution for these people: just go to the optician.
Big or small pupils
Poor vision in the dark can also be caused by medication use, cataracts or a lack of vitamin A. “The latter is rare.”
Another cause is that you have small pupils, which means less light gets in. “This is often the case with older people and cataracts also play a role.” The opposite is also possible; in people with large pupils you often hear that they experience light scattering and therefore see halos around light sources. “They are also known to sometimes have poor vision in the dark,” says Biswane-Vergunst.
For people with large pupils, it can be useful to switch on the interior light of the car while driving. “As a result, the pupil becomes slightly smaller, but that is not always nice for other road users.”
Hereditary disorder
In a few cases, night blindness is more annoying. With the eye disease glaucoma, other diseases of the optic nerve, or with a hereditary disorder of your eyes, such as retinitis pigmentosa. According to the Eye Fund, the latter form of night blindness occurs in 1 in 3,500 people and unfortunately there is little that can be done about it.
The complaint of night blindness often has an underlying cause. That is why, according to Biswane-Vergunst, it is wise to have your eyes checked by an optician or optometrist. “In addition to measuring eye strength, an optometrist can also look at eye health. Optometrists work at many opticians. This makes an eye test done in no time.”