- Reading in the dark or in dim light will cause short sightedness
A common misconception when kids are found reading in dim light or using a torch to read at night is that it will lead to the development of myopia. Our eyes can adapt to reading in low light conditions. Our pupils dilate to allow more light in and we use our rod photoreceptors to see in dim light. There is no evidence to show that the light levels deteriorate vision in any way although it can lead to eye strain and good lighting is an important part of good visual hygiene. There is evidence however to show that prolonged close work such as reading can lead to myopia requiring glasses or increase the amount of existing short sightedness but this is unrelated to the light levels.
- Sitting too close to the TV can damage your eyes
Sitting too close to a TV screen can cause eyestrain and tired eyes and a reduction in the production of melatonin (a sleep hormone) which can result in a disruption in sleep patterns due to exposure to blue light from the screen. This would result in similar exposure to blue light that you would get whilst using a laptop or PC and can be mitigated by using blue light blocking glasses.
There is no evidence however sitting too close to a TV can cause an increase in short sightedness or any significant damage to our eyes. Children in particular have a large amplitude of accommodation and can therefore focus more easily on close objects so may find it more comfortable than adults to sit close to a TV.
- Eating carrots can improve your eyesight
Eating carrots can not improve your eyesight in terms of becoming less short sighted or long sighted. The level of Vitamin A obtained from carrots can however have a beneficial effect in terms of protecting the cornea (surface of the eye) reducing dry eye, protecting from some forms of ocular inflammation and reducing the severity of macular degeneration. Most people’s perception of the term “improve your eyesight” is to reduce the need or dependency on glasses for which there is no evidence.
Another myth is that carrots help you see in the dark. Whilst it is true that vitamin A from carrots help synthesise rhodopsin, a pigment that can help vision in low light conditions, eating carrots would only be beneficial in Vitamin A deficiency and would only improve night vision to a normal levels.
- Wearing glasses or contacts with make your eyes become dependent on them.
Wearing corrective lenses does not deteriorate your vision or make you “more dependent” on your glasses. What can happen is, if you have a mild prescription and don’t wear your glasses your eyes can get good at interpreting blurred images. When you then wear your glasses again your eyes will obviously prefer the clear image through the glasses and it may seem like you need the glasses more but it does not deteriorate the vision in any way and has the added benefit of reducing eyestrain and tired eyes.
- People with colour blindness can only see in black and white
The most common forms of colour blindness result in a difficulty in distinguishing between colours such as red and green and blue and yellow. The public’s perception of colour blindness where everything is experienced as either black or white is actually relatively rare.
The most common form is red green colour blindness where people can perceive colour but would have difficulty distinguishing between green and red tomatoes or for example ripe or unripe bananas.
- There is nothing you can do to prevent a child becoming short-sighted
For children the more time spent doing close concentrated work the more likely they are to become short sighted. Reducing the time spend using hand held digital devices is thus very important and encouraging kids to get outdoors focusing on distant objects is critical.
There are also eyedrop treatments such as Atropine which can halt the progression of myopia as well as treatments such as Orthokeratology which changes the shape of the cornea.
Seamus Flynn is an optometrist and the owner of Sapphire Eyewear a company that sells high quality blue light glasses.
The technology in the lenses block blue light and thus reduce eyestrain, tired eyes and headaches as well as regulates sleep patterns for people who spend time on computers or any type of digital screens.