Make sure your glasses have both UVA and UVB protection and that they block light from the top and sides.

你的眼镜要能防uva还能防uvb，眼镜的上面及两边都不能透光哦。

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Baby falls asleep and gets restful sleep with our Sleepy hat because the flip-down mask works to block light and visual stimulation out.

有我们的安睡帽子，宝贝可以轻松进入梦乡，并得到优质的睡眠，因为翻下来的帽子可以遮挡光线和视觉刺激。

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LCD displays also use shutters, in effect, consisting of liquid-crystal elements whose polarisation can be changed to block light or let it pass.

实际由液晶分子组成的LCD显示屏也采用了百叶窗，分子的极化转变可阻挡光或让其通过。

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In light of threats from the Israelis to block the flotilla of ships, Zehra Ozturk says she and her fellow pro-Palestinian activists from Turkey are not thinking about a blockade.

VOA: standard.2010.05.28

Sandwiching the solar cells inside the device would block some light out and knock down power conversion efficiency even further, Filler cautioned.

FORBES: Magazine Article

The microtrichia are believed to block stray light from reaching the eyelets in much the same way as matte-surfaced hoods around camera lenses.

BBC: 100-eyed bug surprises scientists

But it also carries a coronagraph to block the light from bright objects so it can see more easily nearby, dimmer targets - such as planets circling their stars.

BBC: Science & Environment