Can the eye doctor know the vision distortion is caused by astigmatism or cataracts?

[Bordeaux]

As we all know, astigmatism can cause vision blurry. However, cataracts will also cause vision distortion. I am wondering how can the doctor tell from them?

[Bordelonville]

The eye doctor can tell them easily because they are two different things. The doctor can view the changes in the eye through the pupil. While astigmatism is one type of refractive error caused by an irregular curvature of the eye's cornea.

[Borden]

It is quite easy for the doctor to tell as they are quite different things. You can see cataract through the pupil because it is a physical change in the lens of the eye, while astigmatism are caused by light refracting. They can't be confused.