Blue Light Emission
Here on the Gold Coast, we have many patients asking about using e-readers and digital tablets, and how they may affect their eyes. We are also asked whether they should be used at night before going to sleep. To explain this, we need to understand the devices. E-readers and digital tablets have an elevated intensity of blue light emissions. A while back we mentioned this in our story about the Nikon Relaxsee lenses, which are coated with SeeCoat Blue. We can enhance screen contrast and protect eyes from glare and flicker by reducing the blue light. Learn more about these lenses (here). But how does this blue light affect our sleep?
Using these light-emitting e-readers before you go to sleep reduces your sleep quality, a study by Brigham Women’s Hospital and Harvard Medical School has found. The researchers spent two weeks monitoring 12 volunteer adults with instructions that the subjects were to read either printed books or e-readers before they went to sleep. This was done in a sleep lab in controlled conditions. Falling asleep was more difficult for those who used e-readers, taking 10 minutes longer to fall sleep at night alongside being less alert in the morning than the subjects who read a printed book.
Furthermore, the important REM sleep, the regenerative sleep cycle which is defined by rapid eye movements, was at significantly lower levels. The high concentration of blue light emissions from e-readers and digital tablets was believed to be the contributing factor to this poor sleep quality. The sleep-promoting hormone melatonin is suppressed by the blue light and can shift circadian rhythms. This means it fights the urge to fall asleep so you will stay awake longer. Though only a small number of subjects, this study supports several other studies that have been published over the last year or so: it’s best to put your devices away in the critical last period before you go to sleep.
Aside from reducing your digital device use before sleep, especially if you have difficulty falling asleep or feel tired in the morning, we recommend a blue filtering coating on your lenses to help reduce the blue light affects on your eyes. This can help protect against long term damage to your macula, as well as being beneficial in ensuring your circadian rhythm stays in sync. To find out more, contact one of our four Gold Coast practices below.
Burleigh Heads, 21a James St, Burleigh Heads – 07 5535 2344
Treetops Plaza, Shop 19, 7 Classic Way, Burleigh Waters – 07 5593 7844
MyCentre Nerang, Shop 34b, 57 Station St, Nerang – 07 5502 1277
Tweed Health for Everyone Superclinic, 4/33-35 Corporation Circuit, Tweed Heads South – 07 5524 9659