Yellow-tinted glasses: fashion or necessity?

Is the blue light from screens actually a hazard for your eyes? 

There has been growing concern over recent years about the blue light from electronic devices (such as computers and mobile phones). However, much of this concern is based on studies of limited scientific rigour. 

It’s important to realise that blue light is part of the visible light spectrum and is naturally present in sunlight. It is also found in artificial sources, such as LED screens, fluorescent lights and electronic devices. However, the amount of blue light emitted by screens is much lower than that from the sun, so its impact on eye health is minimal. 

The intensity of blue light from digital devices is between 100 and 1,000 times lower than that from the sun. 

 How do yellow-tinted glasses work? 

Yellow-tinted glasses are designed to filter out part of the blue light, which has a shorter wavelength and scatters more inside the eye. The yellow colour of the lenses is filtered and thus reduces the amount of blue light reaching the eyes.  

However, in practice it’s a bit more complicated than that. To actually protect against blue light, experts explain that a simple yellow tint is not enough.  To block this radiation effectively, a very specific filter is needed to remove a particular wavelength within the blue spectrum. So, in fact, most commercial glasses only filter a small portion of that light.  

 But what does the science say? 

The main ophthalmology societies have made it clear there is no scientific evidence to show that yellow-tinted or blue-light-filtering glasses protect vision or help prevent eye damage. 

One clinical trial investigated whether these filters were effective in reducing the signs and symptoms of digital eye strain (also known as computer vision syndrome), which appears after long sessions in front of a screen. The results showed there were no differences between the filtered glasses and standard clear lenses. 

According to Dr Martí, “Spending many hours in front of screens can tire the eyes because we blink less and may have difficulty focusing. This can lead to dry eyes, itching and eye fatigue; but this is not connected to blue light. The supposed harmful effects of blue light have been spread by studies of little scientific rigour.”  

He also points out that both the Spanish Ophthalmology Society and the American Academy of Ophthalmology “have stated there is no evidence to support these filters. I don’t know of any ophthalmologist who uses or recommends them.” 

What has been demonstrated is that blue light influences the circadian rhythm, the cycle that regulates wakefulness and sleep. Exposure to screens in the evening can make it harder to fall asleep, as it reduces the secretion of melatonin, the hormone that induces sleep. 

 Good habits for protecting your eyesight 

Before buying glasses with filters of unproven effectiveness, the best prevention is to take care of your visual habits. Ophthalmologists recommend: 

1. The 20-20-20 rule. After every 20 minutes of work in front of a computer, look about 20 feet (or 6 m) into the distance for 20 seconds.  

2. Blink often. This helps keep the cornea (the transparent layer of the eye) well hydrated. 

3. Distance and lighting. Keep a minimum distance of 40-50 cm (about 16-20 inches) between your eyes and the screen; and make sure the lighting is adequate. 

4. Limit screen use at night, especially if you have trouble sleeping. 

INFORMATION DOCUMENTED BY: 

Dr Pablo Martí, Ophthalmology Department at Hospital Clínic Barcelona