Your Smart Phone & Your Vision

Melissa Hay, of Visique Optometrists Milford, looks at the effects of phone use on our eyes.

We’re all using our smart phones more and more.  It seems everyone is peering at the little screen of their phone to keep up to date with the world around them and their friends and family.  There has been lots of research into smart phones and the affect they have on vision.  The biggest problem is the length of time people are spending on these devices.  It really should be limited to half an hour.

A study about smartphone use:

We also tend to hold devices such as our smart phones and iPhones closer than printed materials when reading, a new study suggests. This difference could affect vision correction and at Visique Milford Optometrists we are now gauging visual demands based on how you may use smart phones and other new technologies.

The study asked 129 smartphone users to demonstrate how they would hold their mobile device while reading a text message or a typical internet page. The participants wore their usual glasses or contact lenses while reading. The researchers also evaluated the size of the text on the devices, in order to determine whether the working distance at which users held their phones was appropriate for the font size used on the devices.

The findings showed that the ‘working distance’, which is how far away a person holds what they are reading to comfortably view the text, varies depending on what the person is looking at on their phone. For example, researchers found that the average working distance for text messages was 36 centimetres, whereas the average working distance for viewing a webpage was 32 cm.

But those were both closer than the typical working distance of 40 cm used when reading printed text, such as a newspaper.

Holding smart phones at such short distances can place increased demands on the eyes' ability to correct for distance, which is known as accommodation. Short distances can also increase demand on the coordination between eyes, or vergence, compared with the distances typically used when reading printed text.

Smart phones “may present a variety of visual demands that are significantly different in terms of working distances, gaze angle, and text sizes," the study said.

Over time, this increased demand on eyes can lead to conditions such as eyestrain and headaches.

And, about the light…

We recommend that you don’t use your smart phone in bed — and not just because night-time smartphone use messes up your sleep cycle.

The blue light from personal electronic devices has also been linked to serious physical and mental health problems. Blue light is part of the full light spectrum, which means we’re exposed to it by the sun every day. However, night-time exposure to that light, which is emitted at high levels by smart phones, tablets, laptops, and other LED screens, may be damaging your vision. There are reports that the light can accelerate macular degeneration changes and also researches believe there is also a link with cataracts.  

It also suppresses production of the hormone melatonin, which throws off your body’s natural sleep cues.  When your melatonin levels and sleep cycle go haywire, your risk goes up for a wide range of ailments, from depression to cancer.

If you have any concerns about your sight, or have not had a thorough eye exam in the last two years, please drop by our practice on the main street in Milford.  

Visique Milford Optometrists, 155 Kitchener Road, Milford 09 489 4797 milford@visique.co.nz

By Melissa Hay