Preventing dry itchy eyes and maintaining normal vision.

预防眼球干燥、作痒等症状，维持正常的视力。

Another is to look at the image cross-eyed and then shift back to normal vision.

第二种方法是斜着看图，然后转回到正常视角。

The left eye was entirely normal, with normal vision and refraction for his age.

以年龄而言，他的左眼视力和屈折度完全正常。

Normal vision can usually be restored by wearing corrective glasses or contact lenses.

一般视力通常可以经由配戴矫正眼镜或隐形眼镜而恢复。