Author: Daniel Hardiman-McCartney FCOptom, Clinical adviser
Date: 20 September 2019
Apple’s new dark mode for iOS 13 may save battery life, but despite tech folk law, it is unlikely to save you from digital eye strain.
Optometrists may be asked to advise their patients of the merits of dark mode after Apple joins other tech manufacturers in offering iPhone users a dark mode option in addition to the night shift feature already available. The claims that it is better for your eye sight are controversial despite much media attention. Night mode may be useful by reducing the overall screen brightness and being optimised for use in low light environment but there is little evidence available to say whether it is effective at reducing digital eye strain.
The potentially damaging effects of white-background screens, usually are referring to the “blue light,” part of the light spectrum made of short, high-energy wavelengths. A study published in BMJ Ophthalmology noted that blue light could be a factor in eye tiredness, but lists a number of other factors that are also likely to contribute to digital eye strain. A separate study published in the College’s journal Ophthalmic and Physiological Optics concluded that there is lack of high quality evidence to support using blue blocking spectacle lenses for the general population to improve visual performance or sleep quality, alleviate eye fatigue or conserve macular health.
Advice that optometrists may give members of the public
Many people worry that viewing a screen can damage their eyes. There is no evidence of this. In fact, because you can alter the size, brightness and contrast of the display, it can easier and more comfortable to see on a screen compared with looking at things on paper. However, some people find that looking at a screen for a long time is tiring. If you use a device at night using a dark mode or night shift feature maybe helpful, but if you are affected by eye strain we have some additional advice:
Here are some ways to look after your eyes while using your screen:
- Apply the 20-20-20 rule – every 20 minutes look at something 20 feet away for 20 seconds. That will give your eye muscles a rest.
- Try to blink regularly. Focusing on a screen may make you blink less, which may make your eyes dry and uncomfortable.
- Position your device screen so that:
- it is between 40 and 76 centimetres (16 to 30 inches) from your eyes
- it is below the level of your eyes
- there are no distracting reflections, e.g. from a light or window.
- Use a text size that is easy to see.
- Have regular sight tests.
- Wear glasses if you have been prescribed them.
- If you are affected by dry eye, consider using lubricating eye drops.
Evidence in practice on blue blocking spectacles
Digital eye strain: prevalence, measurement and amelioration
Dr Amy Sheppard and Prof James Wolffsohn
The effect of blue‐light blocking spectacle lenses on visual performance, macular health and the sleep‐wake cycle: a systematic review of the literature
Prof John Lawrenson and Dr Laura Downie
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