What makes reflective displays more eye-friendly?

1. Low blue light

The first feature you'll likely find advertised in eye care monitors is lower blue light emissions. Acer, for instance, explains how their VisionCare displays "emit at least 30% less high-energy blue light compared to the industry-standard LCDs...Research suggests this range of high-energy blue light has the greatest potential to cause damage to the eye."



International safety and product testing organizations agree that blue light can be a cause for concern when it comes to eye health. EyeSafe, a North American company, offers the EyeSafe Display Standard—"the most comprehensive set of requirements in low blue light management for the display industry"—based on leading research into the health effects of blue light exposure. That standard is now tested and certified by TÜV Rheinland, an international independent testing company. TÜV Rheinland is an important name in the eye-care monitor market, as they also maintain their own Eye Comfort Certification, a certification you'll find advertised on most product pages for eye-friendly monitors. That certification also lists "low blue light" as one of three criteria for eye comfort.

2. Flicker-free

Next in the list of eye-friendly features is one that hasn't received nearly as much attention as blue light: flicker-free dimming.

In a conventional backlit monitor, the brightness is at least partially controlled by flickering the backlight (a technique called Pulse Width Modulation, or PWM). As an oversimplified example, to create a brightness level of 50%, a conventional monitor can cycle the backlight on and off in equal intervals. If it happens quickly enough (i.e. 200 times per second), we can't perceive the flashing; the image looks stable albeit half as bright.

Unfortunately, this imperceptible flickering seems to cause health issues in sensitive individuals. According to ASUS, these issues can include "eye fatigue, irritation and strains." As a result, most eye care monitors dim the screen without relying on PWM. TÜV Rheinland's Eye Comfort Certification requires compliant monitors to exhibit a "flicker free quality" as well.

3. Ambient light matching

If you've bought a smartphone or tablet in the last decade you're likely familiar with a feature called Auto Brightness (and True Tone) on iOS, or Adaptive Brightness on Android. These features use an ambient light sensor (usually near the front-facing camera) to detect illumination levels in your environment, then adjust the screen's brightness (and color temperature, at least with True Tone) to best match it.

This is important for eye comfort, as our eyes adapt to the overall illumination levels of our environment and not just the screen we may be working on. If something we're looking at is excessively bright or dim compared to its surroundings, eye strain can result. (This is the same reason glare on computer monitors is problematic; the stark difference in brightness between it and other objects in our field of view causes discomfort.) This is especially relevant in windowed offices, as natural light levels vary greatly throughout the day; a monitor without auto-brightness can quickly become uncomfortably bright after the sun sets.

Despite their ubiquity in portable electronics, though, these features aren't yet standard on desktop monitors. Fortunately, eye care monitors are helping to change that. BenQ, the "first monitor manufacturer to prioritize eye health", explains their approach to ambient light matching—which they call Brightness Intelligence Plus:

"The [Brightness Intelligence+] sensor detects screen content and environmental lighting, then adapts the display image accordingly. Headaches, eye strain, and fatigue become a thing of the past."

Samsung and Acer offer similar features in some of their products.

4. Low dimming

Ideally, in low-lit environments, monitors would be able to dim to very low brightness levels to prevent eye strain. Unfortunately, many sufferers of screen-related eye issues find even the lowest brightness settings on most monitors too high for comfort. The users on LEDStrain, for example, a forum dedicated "to help with the impact light-emitting devices have on our health - particularly eye health", list "Minimal brightness is too high" as one of 5 common problems in monitors.

Some manufacturers have taken notice. Acer, in particular, advertises "Low-dimming Technology" on its VisionCare page, a feature which promises "up to 15% darker brightness levels, all adjustable through the on-screen display to best fit your ambient environment".