Esotropia is a condition in which one or both eyes turn towards the nose at different times due to an inability to work together. It is a type of strabismus or misalignment of the eyes. Esotropia has three main causes. Muscular esotropia involves weakness of the medial and lateral rectus, the muscles on the sides of the eyes. When muscles are weak, they don't hold the eye in the correct position, causing misalignment. This is the most common type of esotropia. Farsightedness, or farsightedness, also causes esotropia. A hyperopic person can clearly see objects at a distance but has difficulty seeing objects at close range. When a person is severely farsighted, looking at objects up close can cause the eyes to roll. This type of eye misalignment is called accommodative esotropia. The third cause of esotropia is the least common and least studied. This type involves the brain's inability to use both eyes at the same time because one eye is weaker or blind. When one eye doesn't work properly, the brain focuses its efforts on the functioning eye, severing the connection with the damaged one. If not corrected, this can lead to permanent blindness. Many people with esotropia have a combination of the three types, but all lead to strabismus and impair vision. Sometimes, esotropia is genetic. Scientists have found that it can run in families, often skipping a generation. For example, a grandparent may have it, but his children will not be affected. Later, esotropia will manifest itself in his grandchildren. Scientists continue to research this genetic tendency because they don't know what causes it. When one eye crosses inward toward the nose, diplopia, or double vision, occurs. A person suffering from esotropia sees the...... in the center of the sheet superimposed ......onard Press, Dr. "Esotropia." Strabismus.org. Optometrist Network, 2014. Web. May 17, 2014. .Dorland, W.A. Newman. Dorland's Illustrated Medical Dictionary. 27th edition. Philadelphia: Saunders, 1988. Print."Eye Disorders." The Merick Handbook of Medical Information. Ed. Robert Berkow, MD Whitehouse Station, New Jersey: Merick Research Laboratories, 1997. 1314-315. Print.Miller, Jonathan. The human body. Library of Congress: Dark Horse Production Limited, 1983. Print.Rutstein, Robert P., O.D. “Strabismus: Esotropia and Esotropia.” American Optometric Association. American Optometric Association, 2011. Web. May 17, 2014. “Strabismus.” United States National Library of Medicine. ADAM, Inc., September 17, 2012. Web. May 17 2014. .