在英文中，眼镜度数的单位是diopter /daɪˈɒptə(r)/（屈光度）。

释义：a unit for measuring the power of a lens to refract light (= make it change direction)

屈光度

大家在视力检验报告上就能看到屈光度，如果是-3.5D，这里的D就是diopter的缩写。而-3.5D代表的也就是近视350度。

A "plus" (+) sign in front of the number means you are farsighted, and a "minus" (-) sign means you are nearsighted. These numbers represent diopters, the unit used to measure the correction, or focusing power, of the lens your eye requires. Diopter is often abbreviated "D".

数字前的加号就意味着你是远视，减号则意味着你是近视。这些数字代表屈光度，指能够矫正你眼睛聚焦能力的镜片的单位。Diopter常缩写为"D"。

例句：

I am nearsighted with 2.0 diopters.

我近视200度。

How strong are your glasses?

你的眼镜多少度?/你近视多少度?

*注意这里要用strong来修饰，度数越高，镜片越厚。

How good is your vision?

你视力怎么样?

如果你在对话中和朋友正在围绕着眼镜问题来聊，你也可以直接这么问：

What prescription are your glasses?