Normal vision for a achromatopsic colour-blind person. Courtesy NIH National Eye InstituteThe same view when achromatopsic and myopic.
Find information on thousands of medical conditions and prescription drugs.


Myopia is a refractive defect of the eye in which light focuses in front of the retina. Those with myopia are often described as nearsighted or short-sighted in that they typically can see nearby objects clearly but distant objects appear blurred because the lens cannot flatten enough. The opposite of myopia is hyperopia or "farsightedness". more...

Mac Ardle disease
Macular degeneration
Mad cow disease
Maghazaji syndrome
Mal de debarquement
Malignant hyperthermia
Mallory-Weiss syndrome
Malouf syndrome
Marburg fever
Marfan syndrome
MASA syndrome
Mast cell disease
MAT deficiency
Maturity onset diabetes...
McArdle disease
McCune-Albright syndrome
Mediterranean fever
Megaloblastic anemia
Meleda Disease
Meniere's disease
Mental retardation
Mercury (element)
Metabolic acidosis
Metabolic disorder
Methylmalonic acidemia
Microscopic polyangiitis
Microtia, meatal atresia...
Miller-Dieker syndrome
Mitochondrial Diseases
Mitral valve prolapse
Mobius syndrome
MODY syndrome
Moebius syndrome
Molluscum contagiosum
MOMO syndrome
Mondini Dysplasia
Mondor's disease
Monoclonal gammopathy of...
Morquio syndrome
Motor neuron disease
Moyamoya disease
MPO deficiency
Mullerian agenesis
Multiple chemical...
Multiple endocrine...
Multiple hereditary...
Multiple myeloma
Multiple organ failure
Multiple sclerosis
Multiple system atrophy
Muscular dystrophy
Myalgic encephalomyelitis
Myasthenia gravis
Mycosis fungoides
Myelodysplastic syndromes
Myeloperoxidase deficiency
Myoadenylate deaminase...
Myositis ossificans

Myopia is the most common eyesight problem in the world. About one quarter of the adult population in the United States has myopia. In places like Japan, Singapore and Taiwan, as many as 44% of the adult population is myopic.

Myopia is measured in diopters; specifically, the strength of the corrective lens that must be used to enable the eye to focus distant images correctly on the retina. Myopia of 6.00 diopters or greater is considered high, or severe, myopia. People with high myopia are at greater risk of more acute eye problems such as retinal detachment or glaucoma. They are also more likely to experience floaters.

Mainstream ophthalmologists and optometrists most commonly correct myopia through the use of corrective lenses, such as glasses or contact lenses. It may also be corrected by refractive surgery, such as LASIK. The corrective lenses have a negative dioptric value (i.e. are concave) which compensates for the excessive positive diopters of the myopic eye.


A recent Australian study found that less than 1 in 10 (8.4%) children between the ages of 4 and 12 were myopic . According to an American study published in Archives of Ophthalmology, nearly 1 in 10 children between the ages of 5 and 17 have myopia , and a recent Brazilian study found that nearly 1 in 8 (13.3%) of the students in one city were myopic .

A recent study involving first-year undergraduate students in the United Kingdom found that 50% of British whites and 53.4% of British Asians were myopic.

The prevalence of myopia in adults in the United States has been estimated to be approximately 25%, however, a study of Jordanian adults aged 17 to 40 found that over half (53.7%) were myopic .

Myopia is more common in Asians and Jews than in Whites, and more common in Whites than in Blacks (Jensen, 1998).



  • Genetic Factors - The most widely held theory of the cause of myopia is that it is mainly hereditary. Measures of the heritability of myopia have yielded figures as high as 89%, and recent research has identified genes that may be responsible: defective versions of the PAX6 gene seem to be associated with myopia in twin studies . Under this theory, the eye is slightly elongated front to back as a result of faults during development, causing images to be focused in front of the retina rather than directly on it. It is usually discovered during the pre-teen years between eight and twelve years of age. It most often worsens gradually as the eye grows during adolescence and then levels off as a person reaches adulthood. Genetic factors can work in various biochemical ways to cause myopia, a weak or degraded connective tissue is a very essential one. Genetic factors include an inherited, increased susceptibility for environmental influences like excessive near work, and the fact that some people do not develop myopia in spite of very adverse conditions is a clear indication that heredity is involved somehow in any case.
  • Environmental Factors - Another theory is that myopia is caused by a weakening of the ciliary muscle which controls the eye's lens. The weak muscle is unable to adjust the lens enough to see far distances, causing far-off things to be blurred. This theory states that the muscle's weakness is usually caused by doing lots of "nearwork", like reading books or using a computer screen. Since the eye rarely has to focus on far distances, the muscle is rarely used and, as a result, becomes weak. Since corrective lenses do the ciliary muscle's work for it, proponents of this theory suggest that they make it even weaker, increasing the problem. Instead, they recommend a variety of eye exercises to strengthen the muscle. A problem with this theory is that mainstream ophthalmology and medicine hold that the ciliary muscle is used when focussing at close distances, and is relaxed when accommodating for distant vision. Other theories suggest that the eyes become strained by the constant extra work involved in "nearwork" and get stuck in the near position, and eye exercises can help loosen the muscles up thereby freeing it for far vision. These primarily mechanical models appear to be in contrast to research results, which show that the myopic elongation of the eye can be caused by the image quality, with biochemical processes as the actuator. Common to both views is, however, that extensive near work and corresponding accommodation can be essential for the onset and the progression of myopia. A variation of this theory was touted by William Bates in the early 1900s. Bates claimed that with nearwork and other "stresses", the extraocular muscles would squeeze the eyeball causing it to elongate.
  • Near work. Near work has been implicated as a contributing factor to myopia in many studies. New research from NSU College of Optometry shows that students exposed to extensive "near work" are at a higher risk of developing myopia, whereas taking summer or winter vacations (which amount to extended breaks from near work) will either reduce or stop myopic progression .
  • Combination of Genetic and Environmental Factors - Regardless of the accuracy of the ciliary muscle theory, a high heritability of myopia (as for any other condition) does not mean that environmental factors and lifestyle have no effect on the development of the condition. High heritability simply means that most of the variation in a particular population at a particular time is due to genetic differences. If the environment changes - as, for example, it has by the introduction of televisions and computers - the incidence of myopia can change as a result, even though heritability remains high. From a little bit different point of view it could be concluded that – determined by heritage – some people are at a higher risk to develop myopia when exposed to modern environmental conditions with a lot of extensive near work like reading. In other words, it is often not the myopia itself, which is inherited, but the reaction to specific environmental conditions - and this reaction can be the onset and the progression of myopia. In China, myopia is more common in those with higher education background ; some studies suggesting that nearwork may exacerbate a genetic predisposition to develop myopia .
  • Diet and nutrition - One 2002 article suggested that myopia may be caused by over-consumption of bread in childhood, or in general by diets too rich in carbohydrates, which can lead to chronic hyperinsulinemia. Various other components of the diet, however, were made responsible for contributing to myopia as well, as summarized in a documentation.


[List your site here Free!]

Complex Cases with LASIK: Advanced Techniques and Complication Management $295.00 Short-Term America: The Causes and Cures of Our Business Myopia $23.97
Marketing Myopia $6.00 The Myopia Myth: The Truth About Nearsightedness and How to Prevent It $10.00
Broken Date $0.01 How I Cured My Myopia : Prevent and reverse nearsightedness without glasses, contact lenses and surgery $19.29
The Ostrich Factor : Our Population Myopia $1.00 Excimer Laser Refractive Surgery: Practice and Principles $7.60
Optometric Management of Nearpoint Vision Disorders $77.73 The Art of Lasik $197.65

Clearing up blurry vision: scientists gaze toward causes of myopia
Next time you can't make out a distant highway sign, blame your parents. Scientists in the United Kingdom have found that myopia, or nearsightedness, ...
Myopia and diet - nearsightedness - Nutritional Influences on Illness
Undernutrition Several studies have investigated the relationship between body stature as an index of nutritional status and myopia. While the findings ...
Myopia is the medical term for nearsightedness. People with myopia see objects more clearly when they are close to the eye, while distant objects appear ...
Myopia is the medical term for nearsightedness. People with myopia see objects more clearly when they are close to the eye, while distant objects appear ...
Shortsightedness: a review of causes and interventions - Tips from Other Journals - myopia treatment
The prevalence of myopia (or "shortsightedness") is about 30 to 40 percent in the United States and Europe but reaches 70 to 90 percent in some Asian ...
Is Myopia Genetic?
Research on the human genome is bringing us closer to an answer. For many years the ophthalmic community has debated whether refractive myopia is genetically ...
Demographics * Age range at presentation: 50 years and older * Gender trends: None * Racial trends: None * Refractive error trends: High myopia * Associated ...
HOW ADVERTISING PRACTITIONERS VIEW ETHICS: Moral Muteness, Moral Myopia, and Moral Imagination
ABSTRACT: This study examines how advertising agency personnel perceive, process, and think about ethical issues. We conducted in-depth, elite interviews ...

Home Contact Resources Exchange Links ebay