Which Screen is Best for Your Eyes?

Whether you are working, reading, or mindlessly scrolling social media, screens are our constant companion these days. If you've noticed your eyes are feeling more tired, dry, and irritated than ever, that's because of our new best friend the screen as well. In order to keep our eyes hydrated, our body is internally wired to blink roughly every 13 seconds, releasing the oil that makes up our tear film with every blink. But when we are looking at screens, our blink rates plummet by as much as 66%, meaning less tear film released onto the surface of the eyes, and thus drier eyes. As expected, studies show that people working and reading on screens report significant discomfort. In a 2018 study of 100 medical school students, screen time caused 58.8% of participants to experience eye strain and fatigue, 23.3% reported headaches, and 13% reported blurry vision. In this same study, 75% of the medical students involved stated they would reduce their screen time as a measure to prevent dry eye.  

Which screen is the best for your eyes? Studies show that smaller screens with lower brightness settings, like e-readers or smartphones are the best for visual comfort and ocular surface health!

But reducing screen time may not be that easy. Since the onset of the COVID19 pandemic, average screen time use in the United States has skyrocketed, with reports indicating that the average American adult (age 18+) is spending over 13 hours per day looking at screens. That's up from roughly 10 hours per day reported in 2019 and 8.4 hours per day in 2018. Knowing that cutting screen time when we're being asked to work from home, attend school from home, and entertain ourselves from home is extremely difficult, can we potentially reduce our symptoms of dry eye by at least choosing the least irritating device to look at?

A new study published in Optometry and Vision Science explored just this and found that the screen that you use does in fact matter! The study looked at the ocular surface health and comfort of 31 healthy adults between age 20 to 26 after reading on a variety of different devices. Baseline measurements of each participant's ocular surface was taken before using any screen time, including the Ocular Surface Disease Index (OSDI) questionnaire, the Computer Vision Syndrome Questionnaire, tear meniscus height, Schirmer test, noninvasive tear break-up time, tear film osmolarity, bulbar injection (redness), and pupil size. Participants were then asked to read for 15 minutes on a laptop computer screen, tablet, e-reader, or smartphone and the ocular surface measurements and questionnaires were repeated. 

The Results

The very best ocular surface health and reported comfort were found when participants read on e-readers or smartphones. Reading on the laptop computer produced the worst disturbances of both ocular surface findings and questionnaire indices. Statistically significant differences were seen between computer use and e-reader/smartphone use in both the OSDI and the CVS-Q questionnaire, tear meniscus height, Schirmer test results, and tear break up time. Tear film osmolarity (a measurement of inflammation) and conjunctival injection (redness) was highest after computer use, followed by e-reader use, and then smartphone use. 

Interestingly, the study also compared these results with and without the use of artificial tears. Using artificial tears had no statistically significant effect on any of the ocular surface findings. 

Why does using an e-reader or a smartphone help reduce dry eye signs and symptoms over reading on a computer?

Study author Cristian Talens-Estarelles, MSc writes that the improved dry eye results with e-readers and smartphones are most likely "attributed to a lower gaze angle and the enhanced optical properties of the e-reader," noting that "the e-reader reflects rather than emits light from behind the screen, similar to how a printed paper behaves." 

The advantages of reading from a smartphone or e-reader on the comfort and ocular surface health of our eyes include:

• Smaller screen size. While it may be tempting if your eyes are bothering you to request a larger or even second monitor for work, thinking that a bigger viewing area will make things easier, the science actually shows making monitors larger or using multiple screen monitors is much more uncomfortable for the eyes. In a survey of more than 10,000 adults, only 53% of Americans working on a single screen experienced digital eye strain symptoms, compared to 75% of Americans who used multiple screens.  Larger or multiple screen monitors require our eyes to be open wider and slow blink rate down as our brain focuses on peripheral vision to scan between multiple displays.
• Lower angle of gaze. Research shows that viewing screens with a downward gaze is the most comfortable for the eyes because it encourages a more natural blink rate.  Ergonomic research suggests and optimal screen height of 15-20 degrees below eye level. A disadvantage of larger and multiple screen monitors is that they are typically positioned directly at eye level instead of in this downward position of gaze which increases discomfort significantly.
• Lower brightness levels. Reflections from our screens can cause significant visual discomfort, and studies show the screen we are looking at should never be brighter than the ambient room lighting. E-readers and smartphones, especially when Night-Shift mode is enabled, are superior options at reducing reflections and screen brightness to create a more natural viewing environment. 

And with any screen use, don't forget taking breaks is the most important thing you can do. For every 20 minutes that you are working, reading, or playing on a screen, you should take a 20 second break to blink and look down a hallway or out a window (20 feet away). This is called the 20/20/20 Rule and research shows it's our best protection to keep eyes comfortable and blinking more naturally!

It's all about the blinking when it comes to keeping eyes happy. Study link here