Stress certainly affects every single function in your body. Anxiety itself is known to affect vision. It can cause the pupils to dilate, which lets in more light which can lead to eye pain. It also can contribute to eye strain, which may lead to more vision problems. Anxiety can cause double vision, blurry vision, and in a few rare cases, hallucinations.
But when it comes to whether or not anxiety can cause blindness, the answer is no. There is currently no evidence that anxiety causes true blindness, as in the inability to see.