When you are first diagnosed with AMD you may be shown an Amsler Grid - an array of horizontal and vertical lines - and asked to describe what you see, basically how straight are the lines and where are they most bent.
I found that it was practically impossib le to describe what you see with any accuracy, because if you move your eyes to better image part of the grid, the bends in the lines also move position. So I developed a simpler version, which is just one horizontal and one vertical line, as attached to this post.
Using each eye in turn, keep your gaze fixed on the intersection, note any deviation in the horizontal and vertical lines and write down or draw what you see. Ignore any deviation that you may see in your peripheral vision, just concentrate on the central area.
In general, the worse your condition is, the greater the deviation will be from the straight lines.
One interesting point. I have wet AMD in both eyes and for vertical lines my right eye shows a deviation to the left and my left eye shows a deviation to the right. However, using both eyes, vertical lines appear to be vertical with no deviation - the brain has deduced that both eyes are seeing the same straight line. Horizontal lines are another story though, made worse by my use of varifocal lenses which already distort horizontal lines.
Paul