A day here at the office rarely goes by without a parent asking some very important questions about technology use and the visual system of their child. Our societal dependence on these devices is an extremely new phenomenon and it shows prudent judgement on the part of parents to inquire about possible harmful effects. The fact that these devices and near-centred visual engagement has become ubiquitous over a very short period makes it very easy to feel a false sense of security about their use. The question that begs to be answered is just because we can, does it mean that we should?
While we are not completely certain what the long-term effects of device use will be on our visual systems – and may not be for several decades – it is important to be aware of some of the concerns that are being evaluated and studied at this time. The first of these has to do with the effects of sustained near-work on myopic (or near-sighted) trends in our society. As an organ, our eyes are thought to be evolutionarily geared primarily for distance-based tasks. How do the adaptive pressures of visual engagement at 40cm from your eyes affect this? It would stand to reason that sustained engagement at this distance would be a stimulus to your body to sacrifice distance clarity for near – and therefore result in nearsightedness, or needing glasses for distance tasks. While this link has not been conclusively defined as of yet, many Optometrists are hedging their bets and encouraging practices of visual hygiene that include distance-viewing tasks. This practice of encouraging distance-based tasks stems from a link that we do now know to exist – the more time that a child spends outdoors during childhood, the less likely they are to become nearsighted. Theories around this correlation are based on the the increased large spatial viewing that occurs outdoors, along with potentially positive effects of natural light exposure on visual development. While the reasoning has not been completely defined, I make a point to discuss with parents that the advice of many prior generations has never been more relevant – kids really do need to go outside and play.
The second property of digital devices that is currently being investigated has to do with the distinctive properties of the light they emit. Their intense sharpness, detail and clarity relies on their heavy emission of higher frequency blue light. Blue light is interesting in that it directly affects the level of the hormone melatonin within our body, which regulates our natural circadian rhythm. Intense exposure to this light, especially before going to bed has been found to increase the length of time that it takes for one to fall asleep and reduce the amount of regenerative REM sleep that one experiences. For many of those who have visited their Optometrist recently, you may also be aware of the negative effects that long term exposure to ultraviolet (UV) light can have on the health of your eyes later in life. When we take a look at the colour spectrum, we find that the blue light emitted by digital devices is within 50nm of this ultraviolet light. How exposure to this light will affect visual health remains to be seen, but it’s important to be aware that this is potentially a concern for us moving forward.
With all of the above in mind, I think the point needs to be made that these devices are very much here to stay. The positive benefits of their use are undeniable and ensuring children learn how to access the vast array of information now at their fingertips is extremely important. Moderation and adaptations however are key to limiting some of the downsides associated with their use. As an example of these adaptations, I’m currently typing this entry with a blue light anti-reflective coating on my glasses that limits the higher frequency light coming off of my computer. In addition, I have installed a program on all of my computers that limits blue light emission based on the time of day and I have made sure to focus on maintaining a proper working distance from my device and took a walk around our home after finishing paragraph 3.
For families interested in learning more about healthy adaptive strategies and creating a healthy home media plan, I would encourage working through the outline found here: https://www.healthychildren.org/English/media/Pages/default.aspx#wizard
Until next month,
Paul Rollett, OD