There are a number of eye-conditions that affect our eyes and vision. A comprehensive list of eye-conditions can be can be found within our A-Z of eye-care. Here are some common visual conditions:

Farsightedness

Farsightedness, or Hyperopia, as it is medically termed, is a vision condition in which distant objects are usually seen clearly, but close ones do not come into proper focus. Farsightedness occurs if your eyeball is too short or the cornea has too little curvature, so light entering your eye is not focused correctly.

Common signs of farsightedness include difficulty in concentrating and maintaining a clear focus on near objects, eye strain, fatigue and/or headaches after close work, aching or burning eyes, irritability or nervousness after sustained concentration.

Common vision screenings, often done in schools, are generally ineffective in detecting farsightedness. A comprehensive optometric examination will include testing for farsightedness.

In mild cases of farsightedness, your eyes may be able to compensate without corrective lenses. In other cases, your optometrist can prescribe eyeglasses or contact lenses to optically correct farsightedness by altering the way the light enters your eyes.

Nearsightedness

Near-sightedness, or myopia, as it is medically termed, is a vision condition in which close objects are seen clearly, but objects farther away appear blurred. near-sightedness occurs if the eyeball is too long or the cornea, the clear front cover of the eye, has too much curvature. As a result, the light entering the eye isn’t focused correctly and distant objects look blurred.

Generally, near-sightedness first occurs in school-age children. Because the eye continues to grow during childhood, it typically progresses until about age 20. However, near-sightedness may also develop in adults due to visual stress or health conditions such as diabetes.

A common sign of near-sightedness is difficulty with the clarity of distant objects like a movie or TV screen or the chalkboard in school. A comprehensive optometric examination will include testing for near-sightedness. An optometrist can prescribe eyeglasses or contact lenses that correct near-sightedness by bending the visual images that enter the eyes, focusing the images correctly at the back of the eye. Depending on the amount of near-sightedness, you may only need to wear glasses or contact lenses for certain activities, like watching a movie or driving a car. Or, if you are very near-sighted, they may need to be worn all the time.

What causes near-sightedness?

The exact cause of near-sightedness is unknown, but two factors may be primarily responsible for its development:

  • heredity
  • visual stress

There is significant evidence that many people inherit near-sightedness, or at least the tendency to develop near-sightedness. If one or both parents are near-sighted, there is an increased chance their children will be near-sighted.

Though the tendency to develop near-sightedness may be inherited, its actual development may be affected by how a person uses his or her eyes. Individuals who spend considerable time reading, working at a computer, or doing other intense close visual work may be more likely to develop near-sightedness.

Near-sightedness may also occur due to environmental factors or other health problems:

    • Some people may experience blurred distance vision only at night. This “night myopia” may be due to the low level of light making it difficult for the eyes to focus properly or the increased pupil size during dark conditions, allowing more peripheral, unfocused light rays to enter the eye.
    • People who do an excessive amount of near vision work may experience false or “pseudo” myopia. Their blurred distance vision is caused by over use of the eyes’ focusing mechanism. After long periods of near work, their eyes are unable to refocus to see clearly in the distance. The symptoms are usually temporary and clear distance vision may return after resting the eyes. However, over time constant visual stress may lead to a permanent reduction in distance vision.
    • Symptoms of near-sightedness may also be a sign of variations in blood sugar levels in persons with diabetes or an early indication of a developing cataract.

An optometrist can evaluate vision and determine the cause of the vision problems.

How is near-sightedness treated?

Persons with near-sightedness have several options available to regain clear distance vision. They include:

  • eyeglasses
  • contact lenses
  • orthokeratology
  • laser and other refractive surgery procedures
  • vision therapy for persons with stress-related near-sightedness.

Eyeglasses are the primary choice of correction for persons with near-sightedness. Generally, a single vision lens is prescribed to provide clear vision at all distances. However, for patients over about age 40, or children and adults whose near-sightedness is due to the stress of near vision work, a bifocal or progressive addition lens may be needed. These multifocal lenses provide different powers or strengths throughout the lens to allow for clear vision in the distance and also clear vision up close.

A large selection of lens types and frame designs are now available for patients of all ages. Eye glasses are no longer just a medical device that provides needed vision correction, but can also be a fashion statement. They are available in a wide variety of sizes, shapes, colors and materials that not only correct for vision problems but also may enhance appearance.

For some individuals, contact lenses can offer better vision than eyeglasses. They may provide clearer vision and a wider field of view. However, since contact lenses are worn directly on the eyes, they require regular cleaning and care to safeguard eye health.

Presbyopia

Presbyopia is a vision condition in which the crystalline lens of your eye loses its flexibility, which makes it difficult for you to focus on close objects.

Presbyopia may seem to occur suddenly, but the actual loss of flexibility takes place over a number of years. Presbyopia usually becomes noticeable in the early to mid-40s. Presbyopia is a natural part of the aging process of the eye. It is not a disease, and it cannot be prevented.

Some signs of presbyopia include the tendency to hold reading materials at arm’s length, blurred vision at normal reading distance and eye fatigue along with headaches when doing close work. A comprehensive optometric examination will include testing for presbyopia.

To help you compensate for presbyopia, your optometrist can prescribe reading glasses, bifocals, trifocals or contact lenses. Because presbyopia can complicate other common vision conditions like nearsightedness, farsightedness and astigmatism, your optometrist will determine the specific lenses to allow you to see clearly and comfortably. You may only need to wear your glasses for close work like reading, but you may find that wearing them all the time is more convenient and beneficial for your vision needs.

Because the effects of presbyopia continue to change the ability of the crystalline lens to focus properly, periodic changes in your eyewear may be necessary to maintain clear and comfortable vision.

Astigmatism

Astigmatism is a vision condition that causes blurred vision due either to the irregular shape of the cornea, the clear front cover of the eye, or sometimes the curvature of the lens inside the eye. An irregular shaped cornea or lens prevents light from focusing properly on the retina, the light sensitive surface at the back of the eye. As a result, vision becomes blurred at any distance.

Astigmatism is a very common vision condition. Most people have some degree of astigmatism. Slight amounts of astigmatism usually don’t affect vision and don’t require treatment. However, larger amounts cause distorted or blurred vision, eye discomfort and headaches.

What causes Astigmatism?

Astigmatism occurs due to the irregular shape of the cornea or the lens inside the eye. The cornea and lens are primarily responsible for properly focusing light entering your eyes allowing you to see things clearly.

The curvature of the cornea and lens causes light entering the eye to be bent in order to focus it precisely on the retina at the back of the eye. In astigmatism, the surface of the cornea or lens has a somewhat different curvature in one direction than another. In the case of the cornea, instead of having a round shape like a basketball, the surface of the cornea is more like a football. As a result, the eye is unable to focus light rays to a single point causing vision to be out of focus at any distance.

Sometimes astigmatism may develop following an eye injury or eye surgery. There is also a relatively rare condition called keratoconus where the cornea becomes progressively thinner and cone shaped. This results in a large amount of astigmatism resulting in poor vision that cannot be clearly corrected with spectacles. Keratoconus usually requires contact lenses for clear vision, and it may eventually progress to a point where a corneal transplant is necessary.

How is astigmatism treated?

Persons with astigmatism have several options available to regain clear vision. They include:

  • eyeglasses
  • contact lenses
  • orthokeratology
  • laser and other refractive surgery procedures

Eyeglasses are a common form of correction for persons with astigmatism. Eyeglasses are the primary choice of correction for persons with astigmatism. They will contain a special cylindrical lens prescription to compensate for the astigmatism. This provides for additional lens power in only specific meridians of the lens.

For some individuals, contact lenses can offer better vision than eyeglasses. They may provide clearer vision and a wider field of view. However, since contact lenses are worn directly on the eyes, they require regular cleaning and care to safeguard eye health.

Astigmatism can also be corrected by reshaping the cornea using a highly focused laser beam of light. Two commonly used procedures are photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).

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