Test Your Blue Light Glasses: 3 Checks, Ten Minutes 

You cannot measure spectral transmission at home. You can absolutely establish whether your lenses do something or nothing, which is the question most people actually have. 

Test 1: The blue object test 

The simplest and most informative. 

• Find a strongly saturated blue object — a blue book cover, a blue folder, a blue app icon 

• Look at it in good light with your naked eye 

• Look at it through one lens, covering the other eye 

• Compare 

A lens filtering meaningfully makes the blue look noticeably duller, greyer, or shifted toward green. A lens filtering very little leaves it essentially unchanged. 

No difference at all means minimal filtering in the visible blue range. 

 

Test 2: The white screen test 

This indicates overall tint strength. 

• Open a blank white document or plain white image, full screen 

• Set brightness to a comfortable level 

• Look at it through the lens 

Amber and effective lenses render white as distinctly warm, cream or orange-tinged. Light filtering gives a faint warmth. No perceptible change means very little filtering. 

White contains all wavelengths, so removing blue produces an immediately visible warm shift. That is what makes this test useful. 

Test 3: The RGB block test 

The most controlled of the three. 

• Display a pure blue colour block on your screen using a colour picker or solid-colour image 

• Note how it looks normally 

• View it through the lens 

Strong filtering makes pure blue appear substantially darker, greyer, or nearly black. Weak filtering leaves it recognisably blue. 

Repeat with pure red and pure green. Those should change relatively little, since the lens is meant to filter blue specifically. If everything darkens equally, you own sunglasses rather than a selective blue filter. 

 

What these tests cannot tell you 

• They give you 'substantial', 'some' or 'minimal' — not a percentage 

• They cannot identify which specific wavelengths are filtered, and violet-end versus mid-blue matters considerably for sleep 

• They say nothing about UV protection, which is a separate property 

• Your perception adapts within a minute, so make the comparison quick rather than staring through the lens first 

Reading your result 

• Strong change across all three — substantial filtering, suitable for evening sleep use 

• Moderate change — some filtering, likely light amber, modest benefit 

• Minimal or no change — very little filtering in the visible blue range. Not useless as glasses, but unlikely to deliver the sleep effect the research describes. 

 

If yours test weak 

If sleep was the goal, you need a genuinely tinted pair — amber or red — worn in the two to three hours before bed. 

If daytime screen comfort was the goal, the honest answer is that even a strongly filtering pair has weak evidence for that, so the upgrade would not help either. Breaks, ergonomics and an eye examination will. 

This article is for general information and is not medical advice.