Those with Emmetropia have perfect vision. They can see clearly both far and near with a minimum effort so there's no visual interference at any distance.

Astigmatism is the streaking of vision both far and near. This condition is usually present all of the individual’s life so they're unaware of the distortion.  Individuals with astigmatism often develop an amazing ability to recognize very distorted letters on a snellen chart. Because of this they're frequently given a 
false sense of security about their vision by a driving or school screening. The extra effort required to recognize distorted text, where every letter of a word is streaked, often greatly reduces their comprehension of written material. These individuals often do a minimal of reading or near tasks, sometimes resulting in reduced academic performance. Astigmatism is rarely identified by a snellen screening and professional eye examinations are needed for detection.  Glasses or contacts provide correction both far and near.

Hyperopia, inaccurately called "farsightedness" varies throughout an individuals life.

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  1.  Of the Young

Children affected by Hyperopia can often see reasonably well both far and near, However, they have to focus more at near resulting in a shorter attention span. This can result in an individual who does little reading and hurried homework resulting in reduced academic performance.  Rarely are these children identified by a school screening so professional visual examinations are the only method of detecting this visual problem. Glasses or contact lenses are needed for near concentration


    2.  Of Middle Age

These individuals can see well at far, but may experience eye strain when concentrating on far tasks. They often cannot focus clearly at near so multifocal or reading glasses are needed to correct their near vision.


   3.  Of Later Life

These individuals cannot see well far or near as they've lost their focusing ability to overcome the extra effort required  by Hyperopia. Multifocal glasses or contact lenses are needed to correct this condition.
          both far and near.

Individuals with Myopia also referred to as "nearsightedness" have various degrees of far blurriness. They can see clearly and easily at near, and enjoy reading. These individuals are usually good students, but often fail a school screening.  Glasses or contact lenses are utilized to provide clear far vision.

Aging eyes, medically known as presbyopia, is a condition in which the lens of the eye gradually loses its flexibility, making it harder to focus clearly on close objects such as printed words. Distance vision, on the other hand, is usually not affected.

Unfortunately, presbyopia is an inevitable part of aging and cannot be prevented by diet, lifestyle or visual habits. However, it is treatable with several types of corrective lenses, including progressives, bifocals and trifocals, single-vision reading glasses, multifocal contact lenses and monovision therapy.