Roca cape lighthouse in Portugal, West most point of Europe ( Cabo da Roca) Vertical. Roca cape lighthouse in Portugal, West most point of Europe ( Cabo da Roca) Vertical. The obelisk with a large white cross at Cabo da Roca. It is a cape which forms the westernmost extent of mainland Portugal and continental Europe.
The other rows contain letters that are progressively smaller. During an eye exam, your eye doctor will ask you to find the smallest line of text letters that you can make out, and ask you to read it. If you can read the bottom row of letters, your visual acuity is very good.
The tumbling E chart tests the visual acuity of young children and others who can't read letters aloud. [Read more about children's eye exams.] 20/20 vision is considered normal vision, meaning you can read at 20 feet a letter that most human beings should be able to read at 20 feet.