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.
A refraction test is usually given as part of a routine eye examination. It may also be called a vision test. This test tells your eye doctor exactly what prescription you need in your glasses or contact lenses. Normally, a value of 20/20 is considered to be optimum, or perfect vision. Individuals who have 20/20 vision are able to read letters that are 3/8 of an inch tall from 20 feet away.