When it comes to choosing sunglasses, it's essential to understand the concept of Visible Light Transmission (VLT). VLT refers to the amount of light that passes through the lens and reaches your eyes. It is often represented as a percentage and determines the darkness or lightness of the lenses. While many people assume that higher VLT means better sunglasses, that's not necessarily the case.
The VLT of sunglasses is crucial, as it affects your vision and comfort in different lighting conditions. To make an informed decision, it's essential to consider the specific purpose for which you'll be using the sunglasses. Let's explore the various VLT categories and their respective applications.
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Category 0: 80-100% VLT |
Virtually clear lenses suitable for very dim or night conditions, making them more commonly used in ski goggles, eyeglasses, and fashion eyewear rather than sunglasses. |
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Category 1: 40-80% VLT |
Medium-tinted lenses are ideal for overcast and low-light conditions, such as during dusk. They may come in colors like yellow, rose, or amber. |
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Category 2: 18-40% VLT |
Recommended for all-purpose use, especially if your eyes are not sensitive. They are suitable for mixed conditions with intermittent sunshine. |
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Category 3: 10-18% VLT |
Dark and best suited for bright, sunny days and activities like water sports and snow sports. They provide protection against glare and are legal for daytime driving, although they might be too dark for some individuals. |
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Category 4: 0-10% VLT |
Very dark lenses are primarily designed for high altitude trekking, mountaineering, and specialised activities like welding. However, they are not suitable for regular sunglasses and are not legal for driving in the UK due to their limited light transmission. |
When it comes to driving, it's important to choose sunglasses with a VLT between 10-100% during the day. Anything less than 10% may not allow enough light for safe driving and might even be illegal. Consider opting for polarized lenses, which reduce glare from flat surfaces like the road, enhancing visual clarity. However, it's crucial to avoid wearing sunglasses while driving at night or dusk.
Remember, selecting the right VLT for your sunglasses ensures optimal vision and eye protection in different lighting conditions. So, before making a purchase, consider your specific needs and activities to find the perfect pair of sunglasses that offer both style and functionality.
