What does 20/20 vision mean?
20/20 does not mean perfect vision, it means sharp or clear vision measured at a distance of 20 feet.
Astigmatism is a vision condition that causes blurred vision due to an irregular shape of the cornea (the clear front cover of the eye) or an irregularly shaped lens inside the eye. Regular astigmatism usually can be corrected with glasses, contact lenses or refractive surgery. Irregular astigmatism is usually caused by eye injury, eye surgery or keratoconus. These conditions require specialty contact lens fitting.
Computer Vision Syndrome
Computer vision syndrome is a group of problems caused by prolonged computer use, such as eyestrain, headaches, blurred vision and dry eyes. Uncorrected vision problems, such as farsightedness and astigmatism or presbyopia, can lead to computer vision syndrome.
Farsighted, or hyperopia, is a condition that causes difficulty focusing objects that are up close. This condition can cause headaches, eye strain and squinting. Farsightedness and presbyopia both cause blurry vision up close but for different reasons (see below).
Nearsightedness, or myopia, is a vision problem that causes difficulty reading signs or seeing objects at a distance. This condition can also cause headaches, eyestrain and squinting.
Presbyopia usually develops around age 40, where people lose the ability to perform near tasks, such as reading, sewing or working on the computer. People might find themselves holding books or newspapers further out than normal to see clearly. It is different from farsightedness in that it is an age-related condition.
Strabismus (eye turn)
Strabismus is a condition where one or both eyes turn in, out, up or down. It may be all the time or ocassionally. This condition is most common in children and they will not outgrow it.