Before revision: To see it, one needs to look at the right edge of a small red light in a dark room with the right eye (left eye closed) after dark-adapting for about 30 seconds , Then one should see two faint blue arcs starting at the light and heading towards the blind spot.
After revision: To see it, one needs to look at the right edge of a small red light in a dark room with the right eye (left eye closed) after dark-adapting for about 30 seconds ; one should see two faint blue arcs starting at the light and heading towards the blind spot.