如果长时间玩手机，你的视力可能会下降。

Rúguǒ cháng shíjiān wán shǒujī, nǐde shìlì kěnéng huì xiàjiàng.

If you play on your phone for a long time, your eyesight may worsen.

他的视力很好，看远处的字也很清楚。

Tā de shìlì hěn hǎo, kàn yuǎnchù de zì yě hěn qīngchu.

His eyesight is very good; he can see characters in the distance clearly.

为了保护视力，读书时要保持合适的距离和光线。

Wèile bǎohù shìlì, dúshū shí yào bǎochí héshì de jùlí hé guāngxiàn.

To protect your eyesight, you should keep a proper distance and lighting when reading.