Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Did you know?
Atropine was named after the Greek goddess Atropos, the oldest and ugliest of the three sisters known as the Fates, who controlled the destiny of men.
Did you know?
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
Did you know?
The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
Did you know?
If all the neurons in the human body were lined up, they would stretch more than 600 miles.
A Gaze-Direction Cell
Three-cell model
Structure of a typical cell membrane
Climate Change: Volcanoes Timescale
Activation and Clonal Selection of a Cytotoxic T Cell
