Refractive Errors

Farsightedness

Farsightedness or hyperopia is a is a refractive error like astigmatism and myopia. About 25 percent of the population is farsighted. People with hyperopia have difficulty seeing near objects closely, such as reading or sewing.

Farsighted people experience blurry near vision because light rays entering the eye focus behind the retina, the light-sensitive part of the eye, rather than directly on the retina. This happens because the eyeball of a hyperopic person is shorter than normal.

Farsightedness should not be confused with presbyopia. This is a condition that affects the lens usually in the early forties. The eye loses its ability to focus up close so bifocals are needed. Many children are born with farsightedness, which may slowly disappear as the child grows and the eyeball lengthens. However, not all children outgrow their hyperopia. Farsighted patients may complain of headaches, eyestrain, squinting or fatigue when reading, sewing, working on a computer or performing other work in close range. If you experience these symptoms while wearing your glasses or contact lenses, you may need a comprehensive eye examination as well as a new prescription.

This refractive error can be corrected with glasses or contact lenses, which change the way light rays bend into the eyes. If your glasses or contact lens prescription begins with plus numbers, like +2.50, you are farsighted. You may need to wear your vision correction all the time, or only when performing close work.

Refractive surgery is another option for correcting hyperopia, and it may reduce or eliminate your need to wear glasses or contact lenses.

 

Nearsighted and Farsighted

Being nearsighted or farsighted are two of the most common reasons people need glasses and contacts. These two conditions are caused when the eye sees an object inaccurately.

The first condition is myopia. Myopia is more commonly referred to as “Nearsightedness”. This terminology accurately describes this refractive error, in that objects at near are clear, and objects at a distance are blurred. Myopia tends to be somewhat progressive in nature. The bulk of myopic progression seems to occur in the growth and maturation phase of childhood and adolescence.

Additionally, nearpoint work in significant amounts may also promote and increase myopic progression. The blurred vision that is associated with myopia is easily compensated for by glasses, contact lenses or refractive surgery.

The second condition is known as hyperopia. Hyperopia is more commonly referred to as “Farsightedness”. This terminology accurately describes this refractive error, in that objects in the distance are generally more clear than objects at near. Depending on the amount of hyperopia that exists, an individual patient may experience everything from no blur at distance or near, to blur at both distance and near. At lower levels hyperopia may be accommodated for by the focusing muscles in the eye. Higher levels of hyperopia left uncorrected may cause eyestrain, and headaches in addition to blurred vision.

 

Presbyopia

Many people find that their arms are simply too short when they hit the age of 40 – 45 years old. Small print is getting increasingly difficult to read. What is happening to the person’s vision is called presbyopia.

This is a condition that involves the crystalline lens located just behind the iris or colored part of the eye. The lens consists of many layers much like an onion. In childhood and early adulthood it is very flexible providing us with comfortable vision at all distances.

In time the layers of the lens increase to the point of being difficult to focus at near. At the same time the tissues around the lens become less elastic. As a result, it becomes increasingly difficult to focus at near. It is at this time that a near addition lens is needed in aiding near activities.

There are many options now available for the presbyope to help in seeing clearly at near. Bifocals are the most common in which the top of the lens is used for distance and a near area separated by a line is used to focus at near. Reading glasses can also be used for the purpose of near activities only.

An innovative alternative to bifocals or reading glasses is the progressive addition lens or “no line bifocal”. This lens has the distance and near lenses blended which provides clear vision at distance, intermediate, and near.

Contact lenses can also be used for presbyopia in the form of bifocal contacts or monovision where one eye is set for distance viewing and one is set for near viewing. As you can see there are many options available other than getting ones arms lengthened.