Blue light has become one of the most talked-about topics in eye care over recent years. But between marketing claims and genuine science, it's easy to get confused. Let's separate fact from fiction.

What is blue light, exactly?

Blue light is part of the visible light spectrum, with wavelengths between 380 and 500 nanometres. It's emitted by the sun (the biggest source by far), but also by LED screens, smartphones and artificial lighting.

Not all blue light is harmful. In fact, blue-turquoise light (around 480 nm) is essential for regulating your sleep cycle and mood.

Do screens damage your eyes?

Here's the honest truth: current scientific evidence does not support the idea that screens cause permanent eye damage from blue light alone. What screens do cause is digital eye strain — but that's mostly due to:

• Reduced blink rate (we blink 60% less when staring at screens)
• Poor working distance
• Inadequate ambient lighting
• Extended uninterrupted focus time

When does a blue-light filter actually help?

Blue-light filtering lenses can be genuinely useful in specific situations:

• Heavy screen users (8+ hours daily) who experience end-of-day fatigue.
• Night-time screen use: reducing blue-violet light before bed can help with sleep quality.
• Light sensitivity: some people simply feel more comfortable with a slight warm tint.

When it's probably unnecessary

• If you spend most of your day outdoors
• If you already have good visual hygiene habits
• If someone tells you it will "prevent eye damage" — that's overblown

Frequently asked questions

Our professional recommendation

At Óptica Francés, we recommend blue-light filters based on your actual needs, not trends. We'll assess your screen habits, your working environment and your prescription to tell you honestly whether you'd benefit from one.

Have questions about screen fatigue or blue light? Come see us — we'll give you practical, no-nonsense advice.