Value Village ／ Clothing
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Sunglasses are often assumed to protect the eyes in proportion to how dark they are. In fact it is the UV-blocking rate, not the tint, that protects your eyes. Japan has a JIS standard for sunglasses, and knowing how to read its labels changes how you choose. Storage precautions are covered too.
| Label | Meaning | Note |
|---|---|---|
| UV transmittance 1.0% or less (紫外線透過率1.0%以下) | Blocks 99% or more of UV. Japan's JIS label | |
| UV400 | Blocks UV up to a wavelength of 400 nm (international / industry label) | |
| Visible light transmittance (可視光線透過率) | The darkness of the lens. For driving, 8% or more (JIS: under 8% is unsuitable for driving); for night driving, 75% or more | |
| Polarised (偏光) | Reduces reflected glare (water, road surface) | LCD screens can be hard to see |
| Photochromic (調光) | Tint changes with the amount of UV | Changes little inside a car (UV-cut glass) |
[Verify] Check the labelling items and figures in JIS T 7333, and the wording of the Ministry of the Environment manual.
UV protection has nothing to do with tint. A dark lens without UV protection opens the pupil and lets more UV in, so it is worse. Look for "UV transmittance 1.0% or less" or "UV400" on the label.
Regardless of price, if it is labelled, it blocks UV. The differences are lens distortion, durability and frame quality. Avoid unlabelled ones.
Visible light transmittance under 8% is unsuitable for driving (JIS). Dark lenses are dangerous at night and in tunnels. Polarised lenses can make the sat-nav screen hard to read.
A car interior in summer reaches 60–70°C, cracking the coating on plastic lenses and warping the frame. Take them with you, in a case.
Dust scratches them and the coating peels. As with spectacles, rinse with water first, then use a lens cloth (see the glasses-care article). Don't put them in the case lens-down.
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https://www.jisc.go.jp/
https://www.env.go.jp/chemi/uv/uv_manual.html
https://www.megane-japan.or.jp/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
Follow the care label and the maker's instructions for any garment, shoe or bag. For expensive or sentimental items, ask a specialist cleaner or repairer.
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