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.
Eye Strain and Reading in Dim Light. When you walk into a room where light is low, your eye adjusts in several ways. First, the rod and cone cells on the retina begin to produce more light-sensitive chemicals. These chemicals detect light, convert it to an electrical signal and transmit that signal to the brain.o do this, the iris, as well as the muscles that control the shape of your lens, must contract to keep the focused image on the retina. If you read in low light, your visual muscles get mixed signals: Relax to collect the most light, but at the same time, contract to maintain the focused image.