In fact, convex lenses used to correct farsightedness came along nearly 300 years before the concave lenses to correct nearsightedness did.
Farsightedness and nearsightedness are two common eyesight deficiencies.
Farsightedness means the individual has problems seeing close-up and nearsightedness occurs when the individual has problems seeing far away.
The use of concave lenses (lenses that depress inward) to correct nearsightedness is attributed to Nicholas of Cusa and the thought that specific lenses were required to ease various problems with vision prevailed for centuries.
Roughly 145 million of those people could have normal vision with the help of eyeglasses and are simply suffering from problems like nearsightedness, farsightedness, and astigmatism, and many are in low-income countries.
In addition, a child with undiagnosed nearsightedness related to Marfan may have difficulty seeing the blackboard or reading printed materials, and thus do poorly in school.
Most children with Marfan develop nearsightedness, usually in childhood.
Children with Marfan should have a thorough eye examination, including a slit-lamp examination, to test for dislocation of the lens as well as nearsightedness.
The purpose of eyeglasses and contact lenses is to correct or improve the vision of people with nearsightedness (myopia), farsightedness (hyperopia), presbyopia, and astigmatism.
Nearsightedness and lazy eye are also common.
There may be unequal amounts of nearsightedness, farsightedness, or astigmatism, so that one eye will be in focus while the other will not.
Myopia, or nearsightedness, is a condition in which objects in the distance are blurred either because the eye is too long or too strong.
But if a child has become at least 0.25 diopters myopic at this age then there is a 60 percent chance that the child will require spectacle correction for nearsightedness by age 13.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.