Light Glasses & Sleep

The human body reacts to the blue tint of the morning light and the red that comes with sunset. There's lots of anecdotal evidence that glasses with special coloured lenses can help improve night vision; improve sleep patterns and even manage jet lag.If you are an elite athlete like Manchester City and Norway's Erling Haaland (pictured above) it is worth using every technique avaialble which might give you an edge. Haaland thinks that wearing special blue light blocking glasses at night helps his body produce melatonin for better sleep and has improved his football by a couple of percentage points.So what is the science behind light glasses? It all comes down to circadian rhythm, the natural body clock that determines when a person feels awake or sleepy and repeats every 24 hours. This is rhythm is affected by environmental factors, with light and dark having the biggest impact on a 24-hour cycle. 

At this time of year there are less daylight hours and with evening games, when it gets dark ,your body gets tired and gets ready for bed just when you need to be be fully alert and to have the best night vision.The aim when preserving night vision is to use a light source that can be used by our eye's cone receptors, but is poorly seen by our rod receptors. The cones are more prevalent in the centre of retina, the fovea. They are the only receptors able to see detail. We must use these receptors when trying to see any detail, for example for reading numbers.The rod receptors are very sensitive to low levels of light. They cannot see detail and not very prevalent in the centre of retina (which is why you can see things better at night if you direct your fixation a little off to the side). WW2 pilots wore special red glasses, or used red light bulbs, to preserve their night vision and best allow them to see enemy planes, unlit navigation marks etc. when flying at night.

 When, for example, checking a chart, the aim is to use a light that can seen by our cones, because these are the only receptors with enough resolution, but at the same time preserve and avoid bleaching out the more sensitive rods. So the ideal light is well seen by our cones but poorly seen by the rods. Red light is the best wavelength for this.

It is not just night vision which is impacted by special light lenses - players from Sarina Wiegman’s England Women's World Cup squad wore special glasses on the flight to Australia in an effort to combat jet lag. 

We have a large range of blue light blocking lenses available. Some will just block the mild blue light emitted by electronics and others will block all blue light. These lenses are also available in your prescription. If you would like to know more about how these might be of help please come in and have a discussion with a member of our discpensing team.