... any symptoms or vision changes. But without treatment, peripheral (side) vision is usually lost first. Closed-angle ... device with a light and magnifying lens. Your peripheral (side) vision. A visual field test , also called perimetry , measures how well you can see using your side vision. There are different ways to do the test. In general, you'll look straight ahead. Objects will be ... won't cure the disease or restore any vision you have already lost. But it can prevent more vision loss. Your eye care specialist may recommend one or ...