How Do Polarised Spectacle Lenses Work?
Polarised spectacle lenses work by filtering out specific orientations of light waves to reduce glare and improve visual comfort.
Here's how the process works:
The Physics of Light
Light normally vibrates in all directions perpendicular to its path of travel. When light reflects off surfaces like water, roads, snow, or car hoods, it becomes horizontally polarized - meaning the light waves are vibrating primarily in horizontal planes. This horizontally polarised light creates intense glare that can be uncomfortable and reduce visibility.
The Polarising Filter
Polarised lenses contain a special chemical film with molecules aligned in vertical chains, creating what's essentially a microscopic "venetian blind" effect. This filter allows vertically oriented light waves to pass through while blocking horizontally oriented waves.
The Result
By blocking the horizontally polarised reflected light (glare) while allowing vertically polarised light through, polarised lenses significantly reduce glare from reflective surfaces. This makes them particularly useful for:
Driving (reduces glare from roads and other vehicles)
Water activities (cuts glare from water surfaces)
Snow sports (reduces reflection from snow)
General outdoor activities on bright days
Limitations
Polarised lenses can make it difficult to see LCD screens (phones, car dashboards, some digital displays) because these screens often emit polarised light that gets filtered out. They can also make it harder to judge ice conditions while driving, as the reduced glare might mask icy patches on roads.
The technology is quite elegant - it's essentially using the organized molecular structure of the lens material to selectively filter light based on its orientation.