If the length of your eyeball is too short or the cornea has too little curvature, near objects cannot be brought into a sharp and clearly focused image. Some theorists believe that farsightedness is hereditary and others believe that it may result from environmental factors. If you are farsighted, you involuntarily exert extra effort to maintain clear distance vision and even greater effort to see clearly at close range. This extra effort can cause fatigue, tension and discomfort. If the crystalline lens of the eye cannot bring the object into focus, blurred vision occurs.
Many people have some degree of far sightedness.
The condition is only a problem if it significantly affects a person's ability to see. It is estimated that over half the people who wear glasses are wearing them because of a focusing problem due to farsightedness or presbyopia, a natural decrease in focusing ability. Farsightedness can be effectively diagnosed during a comprehensive optometric examination. Common vision screenings, often done in schools, are generally ineffective in detecting farsighted people. This is because these individuals can identify the letters on an eye chart with little difficulty.