Myopia (Greek: μυωπία, muōpia, "nearsightedness" (AmE), "shortsightedness" (BrE))[1] is a condition of the eye where the light that comes in does not directly focus on the retina but in front of it. This causes the image that one sees when looking at a distant object to be out of focus but in focus when looking at a close object.
Eye care professionals most commonly correct myopia through the use of corrective lenses, such as glasses or contact lenses. It may also be corrected by refractive surgery, though there are cases of associated side effects. The corrective lenses have a negative optical power (i.e. are concave) which compensates for the excessive positive diopters of the myopic eye.
Myopia has been classified in various manners.[2][3][4]
Borish and Duke-Elder classified myopia by cause:[3][4]
- Axial myopia is attributed to an increase in the eye's axial length.[5]
- Refractive myopia is attributed to the condition of the refractive elements of the eye.[5] Borish further subclassified refractive myopia:[3]
-
- Curvature myopia is attributed to excessive, or increased, curvature of one or more of the refractive surfaces of the eye, especially the cornea.[5] In those with Cohen syndrome, myopia appears to result from high corneal and lenticular power.[6]
- Index myopia is attributed to variation in the index of refraction of one or more of the ocular media.[5]
Elevation of blood-glucose levels can also cause edema (swelling) of the crystalline lens (hyperphacosorbitomyopicosis) as a result of sorbitol (sugar alcohol) accumulating in the lens. This edema often causes temporary myopia (nearsightedness). A common sign of hyperphacosorbitomyopicosis is blurring of distance vision while near vision remains adequate.[citation needed]
Various forms of myopia have been described by their clinical appearance:[4][7]
- Simple myopia, more common than other types of myopia, is characterized by an eye that is too long for its optical power (which is determined by the cornea and crystalline lens) or optically too powerful for its axial length.[8] Both genetic and environmental factors, particularly significant amounts of near work, are thought to contribute to the development of simple myopia.[8]
- Degenerative myopia, also known as malignant, pathological, or progressive myopia, is characterized by marked fundus changes, such as posterior staphyloma, and associated with a high refractive error and subnormal visual acuity after correction.[5] This form of myopia gets progressively worse over time. Degenerative myopia has been reported as one of the main causes of visual impairment.[9]
- Nocturnal myopia, also known as night or twilight myopia, is a condition in which the eye has a greater difficulty seeing in low-illumination areas, even though its daytime vision is normal. Essentially, the eye's far point of an individual's focus varies with the level of light. Night myopia is believed to be caused by pupils dilating to let more light in, which adds aberrations, resulting in becoming more nearsighted. A stronger prescription for myopic night drivers is often needed. Younger people are more likely to be affected by night myopia than the elderly.[10][11]
- Pseudomyopia is the blurring of distance vision brought about by spasm of the ciliary muscle.[12]
- Induced myopia, also known as acquired myopia, results from exposure to various pharmaceuticals, increases in glucose levels, nuclear sclerosis, oxygen toxicity (e.g., from diving or from oxygen and hyperbaric therapy) or other anomalous conditions.[8] The encircling bands used in the repair of retinal detachments may induce myopia by increasing the axial length of the eye.[13]
-
- Index myopia is attributed to variation in the index of refraction of one or more of the ocular media.[5] Cataracts may lead to index myopia.[14]
- Form deprivation myopia occurs when the eyesight is deprived by limited illumination and vision range,[15] or the eye is modified with artificial lenses[16] or deprived of clear form vision.[17][18] In lower vertebrates, this kind of myopia seems to be reversible within short periods of time.[18] Myopia is often induced this way in various animal models to study the pathogenesis and mechanism of myopia development.[18]
- Nearwork-induced transient myopia (NITM) is defined as short-term myopic far point shift immediately following a sustained near visual task.[19] Some authors argue for a link between NITM and the development of permanent myopia.[20]
Myopia, which is measured in diopters by the strength or optical power of a corrective lens that focuses distant images on the retina, has also been classified by degree or severity:[2]
Myopia is sometimes classified by the age at onset:[2]
- Congenital myopia, also known as infantile myopia, is present at birth and persists through infancy.[8]
- Youth onset myopia occurs in the early childhood or teenage, and the ocular power can keep varying until the age of 21, before which any form of corrective surgery is usually not recommended by ophthalmic specialists around the world.[8]
-
- School myopia appears during childhood, particularly the school-age years.[26] This form of myopia is attributed to the use of the eyes for close work during the school years.[5]
-
- Early adult onset myopia occurs between ages 20 and 40.[8]
- Late adult onset myopia occurs after age 40.[8]
 |
|
 |
|
Near-sighted vision (left), normal vision (right)
|
Myopia presents with blurry distance vision, but generally gives good near vision. In high myopia, even near vision is affected as objects must be extremely close to the eyes to see clearly, and patients cannot read without their glasses prescribed for distance.
A diagnosis of myopia is typically confirmed during an eye examination by an ophthalmologist, optometrist or orthoptist.[27] Frequently an autorefractor or retinoscope is used to give an initial objective assessment of the refractive status of each eye, then a phoropter is used to subjectively refine the patient's eyeglass prescription.
The National Institutes of Health says there is no known way of preventing myopia, and the use of glasses or contact lenses does not affect its progression.[28] There is no universally accepted method of preventing myopia; proposed procedures have not been studied for effectiveness.[8]
Commonly attempted preventive methods include wearing reading glasses, eye drops and participating in more outdoor activities as described below. Some clinicians and researchers recommend plus power (convex) lenses in the form of reading glasses when engaged in close work or reading instead of using single focal concave lens glasses commonly prescribed.[8] The reasoning behind a convex lens's possible effectiveness in preventing myopia is simple to understand: Convex lenses' refractive property of converging light are used in reading glasses to help reduce the accommodation needed when reading and doing close work. Although accommodation is irrelevant in Medina's quantitative model of myopia, it reaches the same conclusion. The model teaches a very simple method to prevent myopia.[29]
For people with presbyopia, whose eyes' lenses can not accommodate enough for very near focus, reading glasses help converge the light before it enters the eye to complement the refractive power of the eye lens, so near objects focus clearly on the retina.[30] By reducing the focusing effort needed (accommodation), reading glasses or convex lenses essentially relax the focusing ciliary muscles and may consequently reduce chances of developing myopia.[31] Inexpensive nonprescription reading glasses are commonly sold in drug stores and dollar stores. Alternatively, reading glasses fitted by optometrists have a wider range of styles and lens choices.[32]
A recent Malaysian study reported in New Scientist[33] suggested undercorrection of myopia caused more rapid progression of myopia.[34] However, the reliability of these data has been called into question.[35] Many myopia treatment studies suffer from any of a number of design drawbacks: small numbers, lack of adequate control group, failure to mask examiners from knowledge of treatments used, etc.
Pirenzepine eyedrops had a limited effect on retarding myopic progression in a recent, placebo-controlled, double-blind, prospective-controlled study.[36]
Researchers at the University of Cambridge have found that a lack of outdoor play could be linked to myopia.[37]
Glasses are commonly used to address near-sightedness.
Compensating for myopia using a corrective lens.
Eyeglasses, contact lenses, and refractive surgery are the primary options to treat the visual symptoms of those with myopia. Lens implants are now available offering an alternative to glasses or contact lenses for myopics for whom laser surgery is not an option. Orthokeratology is the practice of using special rigid contact lenses to flatten the cornea to reduce myopia. Occasionally, pinhole glasses are used by patients with low-level myopia. These work by reducing the blur circle formed on the retina, but their adverse effects on peripheral vision, contrast and brightness make them unsuitable in most situations.
Glasses may have to potential to make the eyes worse, as they increase the accommodation needed by the eyes to focus. Evidence of this can be seen when people with higher prescriptions have a harder time with activities like reading because their eyes grow tired faster. Stronger prescriptions require a higher accommodation by the eyes to focus through them, which can, over time, worsen eyesight, requiring yet another prescription, in a continuous but quickening cycle. Contact lenses of equivalent prescription may not result in the same effect as eyeglasses, as they are closer to the eyes and may require less accommodation.[38] This form of myopia is attributed to the use of the eyes for close work during the school years.[5]
Glasses work by using optical lenses bringing the image a viewer closer so that it can be focused by their myopic eyes. Large amouts of near work while wearing glasses can be very detrimental to the eyes and can be a cause of worsening nearsightedness. However, the eyestrain caused by not wearing glasses when they are needed can also be a risk factor. The best way to avoid needing new lenses is by reducing the amount of near work, which forces the eyes into a continuous near-focusing position that eventually causes or increases myopia, by taking frequent breaks from near work, and by only wearing glasses when they are needed. Reading glasses can also be worn during near work to decrease the strain on the eye, especially when already wearing corrective lenses, as they work in the opposite fashion to normal lenses[39]. Using this practice may have the potential to prevent nearsightedness or slow its progression.
 |
|
 |
|
Prismatic color distortion shown with a camera set for nearsighted focus, and using −9.5 diopter eyeglasses to correct the camera's myopia. (left) Close-up of color shifting through corner of eyeglasses. The light and dark borders visible between color swatches do not exist. (right)
|
For people with a high degree of myopia, very strong eyeglass prescriptions are needed to correct the focus error. However, strong eyeglass prescriptions have a negative side effect in that off-axis viewing of objects away from the center of the lens results in prismatic movement and separation of colors, known as chromatic aberration. This prismatic distortion is visible to the wearer as color fringes around strongly contrasting colors. The fringes move around as the wearer's gaze through the lenses changes, and the prismatic shifting reverses on either side, above, and below the exact center of the lenses. Color fringing can make accurate drawing and painting difficult for users of strong eyeglass prescriptions.
Strongly nearsighted wearers of contact lenses do not experience chromatic aberration because the lens moves with the cornea and always stays centered in the middle of the wearer's gaze.
Various methods have been employed in an attempt to decrease the progression of myopia.[40] Dr Chua Weihan and his team at National Eye Centre Singapore have conducted large scale studies on the effect of atropine of varying strength in stabilizing, and in some case, reducing myopia. The use of reading glasses when doing close work may provide success by reducing or eliminating the need to accommodate. Altering the use of eyeglasses between full-time, part-time, and not at all does not appear to alter myopia progression.[39][41] The American Optometric Association's Clinical Practice Guidelines for Myopia refers to numerous studies which indicated the effectiveness of bifocal lenses and recommends it as the method for "Myopia Control".[8] In some studies, bifocal and progressive lenses have not shown significant differences in altering the progression of myopia.[40] More recently robust studies on children have shown that Orthokeratology[42] and Centre Distance bifocal contact lenses[43] may arrest myopic development.
Scleral reinforcement surgery is a surgical procedure aimed to cover the thinning posterior pole with a supportive material to withstand intraocular pressure and prevent further progression of the posterior staphyloma. The strain is reduced, although damage from the pathological process cannot be reversed. By stopping the progression of the disease, vision may be maintained or improved.[44]
A number of alternative therapies exist including eye exercises and relaxation techniques, such as the Bates method. However, the efficacy of these practices is disputed by scientists and eye care practitioners.[45] A 2005 review of scientific papers on the subject concluded that there was "no clear scientific evidence" that eye exercises were effective in treating myopia.[46]
In the 1980s and 1990s, biofeedback created a flurry of interest as a possible treatment for myopia. A 1997 review of this biofeedback research concluded "controlled studies to validate such methods ... have been rare and contradictory."[47] One study found that myopes could improve their visual acuity with biofeedback training, but that this improvement was "instrument-specific" and did not generalise to other measures or situations.[48] In another study, an "improvement" in visual acuity was found, but the authors concluded this could be a result of subjects learning the task.[49] Finally, in an evaluation of a training system designed to improve acuity, "no significant difference was found between the control and experimental subjects".[50]
The global prevalence of refractive errors has been estimated from 800 million to 2.3 billion.[51] The incidence of myopia within sampled population often varies with age, country, sex, race, ethnicity, occupation, environment, and other factors.[25][52] Variability in testing and data collection methods makes comparisons of prevalence and progression difficult.[53]
The prevalence of myopia has been reported as high as 70–90% in some Asian countries, 30–40% in Europe and the United States, and 10–20% in Africa.[52] Myopia is less common in African people and associated diaspora.[25] In Americans between the ages of 12 and 54, myopia has been found to affect African Americans less than Caucasians.[54]
In some parts of Asia, myopia is the norm.
Singapore is believed to have the highest prevalence of myopia in the world; up to 80 percent of people there have myopia. But the accurate figure is unknown.[55]
China's myopia rates is 31 percent: 400 million of its 1.3 billion people are myopic. The prevalence of myopia in high school in China is 77.3%, and in college is more than 80%.[56]
In some areas, such as China, India and Malaysia, up to 41% of the adult population is myopic to −1.00 dpt,[57] up to 80% to −0.5dpt.[58]
A study of Jordanian adults aged 17 to 40 found over half (53.7%) were myopic.[59]
However, some research suggests the prevalence of myopia in India in the general population is only 6.9%.[60][61]
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.[62]
In Greece, the prevalence of myopia among 15 to 18 year old students was found to be 36.8%.[60]
A recent review found that 26.6% of Western Europeans aged 40 or over have at least −1.00 diopters of myopia and 4.6% have at least −5.00 diopters.[63]
Myopia is common in the United States, with research suggesting this condition has increased dramatically in recent decades. In 1971-1972, the National Health and Nutrition Examination Survey provided the earliest nationally representative estimates for US myopia prevalence, and found the prevalence of myopia in persons aged 12–54 was 25.0%. Using the same method, in 1999-2004, myopia prevalence was estimated to have climbed to 41.6%.[64]
A study of 2,523 children in grades 1 to 8 (age, 5–17 years) found nearly 1 in 10 (9.2%) have at least − 0.75 diopters of myopia .[65] In this study, 12.8% had at least +1.25 D hyperopia (farsightedness), and 28.4% had at least 1.00-D difference between the 2 principal meridians (cycloplegic autorefraction) astigmatism. For myopia, Asians had the highest prevalence (18.5%), followed by Hispanics (13.2%). Caucasian children had the lowest prevalence of myopia (4.4%), which was not significantly different from African Americans (6.6%).[65]
A recent review found 25.4% of Americans aged 40 or over have at least −1.00 diopters of myopia and 4.5% have at least −5.00 diopters.[63]
In Australia, the overall prevalence of myopia (worse than −0.50 diopters) has been estimated to be 17%.[66] In one recent study, less than 1 in 10 (8.4%) Australian children between the ages of 4 and 12 were found to have myopia greater than −0.50 diopters.[67] A recent review found that 16.4% of Australians aged 40 or over have at least −1.00 diopters of myopia and 2.5% have at least −5.00 diopters.[63]
In Brazil, a 2005 study estimated that 6.4% of Brazilians between the ages of 12 and 59 had −1.00 diopter of myopia or more, compared with 2.7% of the indigenous people in northwestern Brazil.[68] Another found nearly 1 in 8 (13.3%) of the students in the city of Natal were myopic.[69]
A number of studies have shown the incidence of myopia increases with level of education,[60][54] and many studies[70] have shown a correlation between myopia and a higher intelligence quotient (IQ).
A 2008 literature review writes that studies in several nations have found a relationship between myopia and higher IQ and between myopia and school achievement. A common explanation for myopia is near-work. Regarding the relationship to IQ, several explanations have been proposed. One is that the myopic child is better adapted at reading, and reads and studies more, which increases intelligence. The reverse explanation is that the intelligent and studious child reads more, which causes myopia. Another is that myopic children have an advantage at IQ testing which is near-work because of less eye strain. Still another explanation is that pleiotropic gene(s) affect the size of both brain and eyes simultaneously. According to the two most recent studies, higher IQ may be associated with myopia in schoolchildren, independent of books read per week.[71]
Other personal characteristics, such as value systems, school achievements, time spent in reading for pleasure, language abilities and time spent in sport activities correlated to the occurrence of myopia in studies.[72][73][74]
Heredity appears as an important factor associated with juvenile myopia, with smaller contributions from more near work, higher school achievement and less time in sports activity.[75]
The terms "myopia" and "myopic" (or the common terms short sightedness or 'short sighted' or "near sighted") have been used metaphorically to refer to cognitive thinking and decision making that is narrow in scope or lacking in concern for wider interests or longer-term consequences.[76] It is often used to describe a decision that may be beneficial in the present, but detrimental in the future, or a viewpoint that fails to consider anything outside a very narrow and limited range. Hyperopia, the biological opposite of myopia, is also used as a metaphor for those who exhibit "far-sighted" behavior; that is, overprioritizing long-term interests at the expense of present enjoyment.[77]
Many instances of myopic individuals have emerged in popular culture, though not always accurately. One such instance is in William Golding's Nobel Prize-winning novel Lord of the Flies, which features a character named Piggy who is very nearsighted, and as a result, wears thick glasses. The children (who are marooned on an isolated island alone) use Piggy's glasses in the same manner as a magnifying glass might be used to start fires. However, if Piggy is truly myopic and not hyperopic, starting fires with his glasses would be impossible. Myopia is corrected through the use of diverging lenses to properly focus light on the retina.[78] These lenses do not converge light in a single point—as would be required to start a fire—but rather scatter it. If Piggy were hyperopic, he would have convex, converging lenses, so they would theoretically be able to serve this purpose.[79]
Normally eye development is largely genetically controlled, but it has been shown that the visual environment is an important factor in determining ocular development.
Genetically, linkage studies have identified 18 possible loci on 15 different chromosomes that are associated with myopia, but none of these loci are part of the candidate genes that cause myopia. Instead of a simple one-gene locus controlling the onset of myopia, a complex interaction of many mutated proteins acting in concert may be the cause. Instead of myopia being caused by a defect in a structural protein, defects in the control of these structural proteins might be the actual cause of myopia.[80]
To induce myopia in lower as well as higher vertebrates, translucent goggles can be sutured over the eye, either before or after natural eye opening.[81] Form-deprived myopia induced with a diffuser, like the goggles mentioned, shows significant myopic shifts.[82] Anatomically, the changes in axial length of the eye seem to be the major factor contributing to this type of myopia.[83] Diurnal growth rhythms of the eye have also been shown to play a large part in form-deprived myopia. Chemically, daytime retinal dopamine levels drop about 30%.[84]
Normal eyes grow during the day and shrink during the night, but occluded eyes are shown to grow both during the day and the night. Because of this, form-deprived myopia is a result of the lack of growth inhibition at night rather than the expected excessive growth during the day, when the actual light-deprivation occurred.[85] Elevated levels of retinal dopamine transporter (which is directly involved in controlling retinal dopamine levels) in the RPE have been shown to be associated with FDM.[86]
Dopamine is a major neurotransmitter in the retina involved in signal transmission in the visual system. In the retinal inner nuclear layer, a dopaminergic neuronal network has been visualized in amacrine cells. Also, retinal dopamine is involved in the regulation of electrical coupling between horizontal cells and the retinomotor movement of photoreceptor cells.[87] Although FDM-related elongations in axial length and drops in dopamine levels are significant, after the diffuser is removed, a complete refraction recovery is seen within four days in some laboratory mice. Although significant, what is even more intriguing is that within just two days of diffuser removal, an early rise and eventual normalization of retinal dopamine levels in the eye are seen. This suggests dopamine participates in visually guided eye growth regulation, and these fluctuations are not just a response to the FDM.[88]
L-Dopa has been shown to re-establish circadian rhythms in animals whose circadian rhythms have been abolished. Dopamine, a major metabolite of levodopa, releases in response to light, and helps establish circadian clocks that drive daily rhythms of protein phosphorylation in photoreceptor cells. Because retinal dopamine levels are controlled on a circadian pattern, intravitreal injection of L-dopa in animals that have lost dopamine and circadian rhythms has been shown to correct these patterns, especially in heart rate, temperature, and locomotor activity.[84] The occluders block light completely for the animals, which does not allow them to establish correct circadian rhythms, which leads to dopamine depletion. This depletion can be rectified with injections of L-dopa and hopefully contribute to the recovery from FDM.
- L-Dopa metabolism is important to consider due to its extensive presystemic metabolism, rapid absorption in the proximal small intestine and short plasma half-life. The major metabolites of L-dopa are dopamine, dihydroxyphenylacetic acid, homovanillic acid, and 3-O-methyldopa and 3-methoxytyramine.[89] Levodopa can be converted into dopamine in the presence of aromatic L-amino acid decarboxylase (L-AAAD).[90] L-AAAD activity in rat retinas is modulated by environmental light,[91] and this modulation is associated with dopamine D1 receptors[92] and alpha 2 adrenoceptors.[93] Also, the synthesis and release of dopamine are light dependent, and light accelerates the formation of dopamine from exogenous L-Dopa.
- Past treatments with dopamine has been used as the gold-standard drug in the treatment of Parkinson's disease and low-dose administration of the drug has been the most effective treatment of Parkinson’s. Possible treatments involving dopamine in preventing a decrease in visual acuity have shown to be successful in the past. L-Dopa treatment in children with amblyopia showed an improvement in visual acuity.[94] In rabbits, injections of dopamine prevented the myopic shift and vitreous chamber and axial elongation typically associated with FDM.[95] In guinea pigs, systemic L-dopa has been shown to inhibit the myopic shift associated with FDM, and has compensated for the drop in retinal dopamine levels.[96] These experiments show promise in treating myopia in humans.
- Side effects of L-dopa have been experimentally determined. L-Dopa and some of its metabolites have been shown to have pro-oxidant properties, and oxidative stress has been shown to increase the pathogenesis of Parkinson's disease.[97] This promotion of free-radical formation by L-dopa does seem to directly affect its possible future treatment of myopia because free-radicals could cause further damage to those proteins responsible for controlling structural proteins in the eye. Levodopa and some of its metabolites such as dopa/dopamine quinone have also been shown to be toxic for nigral neurons.[98] This toxic effect must be analyzed before treatment with levodopa for myopia to prevent damaging effects to these neurons.
In guinea pigs, intraperitoneal injections of L-dopa have shown to inhibit the myopic shift associated with FDM and have compensated to the drop in retinal dopamine levels. In this study specifically, 60 animals were used and the L-dopa treatments inhibited the myopic shift (from −3.62 ± 0.98 D to −1.50 ± 0.38 D; p < 0.001) due to goggles occluding and compensated retinal dopamine (from 0.65 ± 0.10 ng to 1.33 ± 0.23 ng; p < 0.001). Daily L-dopa (10 mg/kg) was shown to increase the dopamine content in striatum. The axial length and retinal dopamine changes were positively correlated in the normal control eyes, deprived eyes, and L-dopa-treated deprived eyes. The increase in retinal dopamine and subsequent retardation of myopia may be associated with the fact that exogenous L-dopa was converted into dopamine. This suggests retinal dopaminergic function in the development of form-deprivation myopia in guinea pigs. The inhibitory effect of L-dopa on FDM may be associated with the fact that retinal L-AAAD can convert it into dopamine to balance the deficiency in the retina of the deprived eyes.[96]
- Areas of future research include intraperitoneal injection of L-dopa; its use at 10 mg/kg could not completely suppress the development of form-deprivation myopia. Perhaps the dose may be too low to completely suppress myopia. Another possibility of the incomplete suppression of myopia may be because it is a complex process, and retinal dopamine content is only one factor. It is also unclear whether systemic application of L-dopa is able to suppress the development of form-deprivation myopia.
- ^ "Online Etymology Dictionary". Etymonline.com. http://www.etymonline.com/index.php?term=myopia. Retrieved 2010-07-29.
- ^ a b c Grosvenor T (July 1987). "A review and a suggested classification system for myopia on the basis of age-related prevalence and age of onset". Am J Optom Physiol Opt 64 (7): 545–54. PMID 3307441.
- ^ a b c Borish, Irvin M. (1949). Clinical Refraction. Chicago: The Professional Press.
- ^ a b c Duke-Elder, Sir Stewart (1969). The Practice of Refraction (8th ed.). St. Louis: The C.V. Mosby Company. ISBN 0-7000-1410-1.
- ^ a b c d e f g h i j k Cline, D; Hofstetter HW; Griffin JR (1997). Dictionary of Visual Science (4th ed.). Boston: Butterworth-Heinemann. ISBN 0-7506-9895-0.
- ^ Summanen, P; Kivitie-Kallio, S; Norio, R; Raitta, C; Kivelä, T (2002). "Mechanisms of myopia in Cohen syndrome mapped to chromosome 8q22". Invest. Ophthalmol. Vis. Sci. 43 (5): 1686–1693. PMID 11980891.
- ^ Goss, DA; Eskridge JB (1988). "Myopia". In Amos, JB (ed). Diagnosis and management in vision care. Boston: Butterworths. p. 445. ISBN 0-409-95082-3. OCLC 14967262.
- ^ a b c d e f g h i j American Optometric Association. Optometric Clinical Practice Guideline: Care of the patient with myopia. 1997.
- ^ Li CY, Lin KK, Lin YC, Lee JS (March 2002). "Low vision and methods of rehabilitation: a comparison between the past and present". Chang Gung Med J 25 (3): 153–61. PMID 12022735.
- ^ The Eyecare Trust. Night Driving – The Facts. OR Eye care advice for driving in the dark January 26, 2005. [PDF]
- ^ Chen JC, Schmid KL, Brown B. The autonomic control of accommodation and implications for human myopia development: a review. Ophthalmic Physiol Opt. 2003 Sep;23(5):401–22
- ^ Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainsville, Florida: Triad Publishing Company, 1990.
- ^ Vukojević, N; Sikić J, Curković T, Juratovac Z, Katusic D, Saric B, Jukic T (2005). "Axial eye length after retinal detachment surgery". Collegium antropologicum 29 (Suppl 1): 25–27. PMID 16193671.
- ^ Metge, P; Donnadieu M (1993). [Myopia "and cataract"] (in French). La Revue du praticien 43 (14): 1784–1786. PMID 8310218. Myopia.
- ^ Young, FA (1962). "The effect of nearwork illumination level on monkey refraction". Am J Optom and Arch Am Acad Optom 39 (2): 60–67.
- ^ Zhu, Xiaoying; Tae Woo Park, Jonathan Winawer, and Josh Wallman (2005). "In a Matter of Minutes, the Eye Can Know Which Way to Grow". Investigative Ophthalmology and Visual Science 46 (7): 2238–2241. DOI:10.1167/iovs.04-0956. PMID 15980206.
- ^ Wallmann, J; MD Gottlieb, V Rajaram, LA Fugate-Wentzek (1987). "Local retinal regions control local eye growth and myopia". Science 237 (4810): 73–77. DOI:10.1126/science.3603011. JSTOR 1699607. PMID 3603011.
- ^ a b c Shen, W; Vijayan M, Sivak JG (2005). "Inducing form-deprivation myopia in fish". Invest. Ophthalmol. Vis. Sci. 46 (5): 1797–1803. DOI:10.1167/iovs.04-1318. PMID 15851585. http://www.iovs.org/cgi/content/full/46/5/1797.
- ^ Ong, E; KJ Ciuffreda (1995). "Nearwork-induced transient myopia: a critical review". Doc Ophthalmol. 91 (1): 57–85. DOI:10.1007/BF01204624. PMID 8861637.
- ^ Ciuffreda, KJ; B. Vasudevan (2008). "Nearwork-induced transient myopia (NITM) and permanent myopia—is there a link?". Ophthalmic Physiol Opt. 28 (2): 103–114. DOI:10.1111/j.1475-1313.2008.00550.x. PMID 18339041.
- ^ "Glaucoma." EyeMDLink.com. Retrieved August 27, 2006.
- ^ Larkin GL. "Retinal Detachment." eMedicine.com. April 11, 2006.
- ^ "More Information on Glaucoma." AgingEye Times. Retrieved August 27, 2006.
- ^ Messmer, DE (1992). "Retinal detachment" (in german). Schweiz Rundsch Med Prax. 81 (19): 622–625. PMID 1589678.
- ^ a b c Verma A, Singh D. "Myopia, Phakic IOL." eMedicine.com. August 19, 2005.
- ^ Morgan I, Rose K (January 2005). "How genetic is school myopia?". Prog Retin Eye Res 24 (1): 1–38. DOI:10.1016/j.preteyeres.2004.06.004. PMID 15555525.
- ^ "ranzco". Ranzco.edu. http://www.ranzco.edu/orthoptists-and-prescribing-in-nsw/view?searchterm=None. Retrieved 2010-07-29.
- ^ National Institutes of Health. "Nearsightedness". 2010. [1]
- ^ Medina A. (1987). "A model for emmetropization The effect of Corrective lenses". Acta ophthalmologica 65: 555–7.
- ^ "Presbyopia". Aoa.org. http://www.aoa.org/x4697.xml. Retrieved 2010-07-29.
- ^ "Myopia (Nearsightedness)". Aoa.org. http://www.aoa.org/myopia.xml#1. Retrieved 2010-07-29.
- ^ "Reading Glasses: What You Should Know". AllAboutVision.com. http://www.allaboutvision.com/over40/readers.htm. Retrieved 2010-07-29.
- ^ Andy Coghlan and Michael Le Page (20 November 2002). "Eye correction is seriously short sighted". New Scientist. http://www.newscientist.com/article.ns?id=dn3082.
- ^ Chung K, Mohidin N, O'Leary DJ (October 2002). "Undercorrection of myopia enhances rather than inhibits myopia progression". Vision Res. 42 (22): 2555–9. DOI:10.1016/S0042-6989(02)00258-4. PMID 12445849. http://linkinghub.elsevier.com/retrieve/pii/S0042698902002584.
- ^ The Wildoset Lab.. "Controlling Myopia Progression – A Confusing Story". Archived from the original on December 25, 2005. http://web.archive.org/web/20051225120626/http://vision.berkeley.edu/wildsoet/myopiaNews/controllingMyopia.html. Retrieved 2006-09-01.
- ^ Siatkowski R, Cotter S, Miller J, Scher C, Crockett R, Novack G (2004). "Safety and efficacy of 2% pirenzepine ophthalmic gel in children with myopia: a 1-year, multicenter, double-masked, placebo-controlled parallel study.". Arch Ophthalmol 122 (11): 1667–74. DOI:10.1001/archopht.122.11.1667. PMID 15534128.
- ^ Dr Justin Sherwin (2011-10-25). "Lack of outdoor play linked to short-sighted children". BBC News. http://www.bbc.co.uk/news/health-15427954. Retrieved 2011-10-25.
- ^ Morgan I, Rose K (January 2005). "How genetic is school myopia?". Prog Retin Eye Res 24 (1): 1–39. DOI:10.1016/j.preteyeres.2004.06.004. PMID 15555525.
- ^ a b Ong E, Grice K, Held R, Thorn F, Gwiazda J (June 1999). "Effects of spectacle intervention on the progression of myopia in children". Optom Vis Sci 76 (6): 363–9. DOI:10.1097/00006324-199906000-00015. PMID 10416930.
- ^ a b Saw SM, Gazzard G, Au Eong KG, Tan DT (November 2002). "Myopia: attempts to arrest progression". Br J Ophthalmol 86 (11): 1306–11. DOI:10.1136/bjo.86.11.1306. PMC 1771373. PMID 12386095. http://bjo.bmj.com/cgi/pmidlookup?view=long&pmid=12386095.
- ^ Pärssinen O, Hemminki E, Klemetti A (July 1989). "Effect of spectacle use and accommodation on myopic progression: final results of a three-year randomised clinical trial among schoolchildren". Br J Ophthalmol 73 (7): 547–51. DOI:10.1136/bjo.73.7.547. PMC 1041798. PMID 2667638. http://bjo.bmj.com/cgi/pmidlookup?view=long&pmid=2667638.
- ^ The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Cho P, Cheung SW, Edwards M. Curr Eye Res. 2005 Jan;30(1):71–80.
- ^ Aller TA, Wildsoet C (July 2008). "Bifocal soft contact lenses as a possible myopia control treatment: a case report involving identical twins". Clin Exp Optom 91 (4): 394–9. DOI:10.1111/j.1444-0938.2007.00230.x. PMID 18601670.
- ^ Ward, B., Tarutta, E., & Mayer, M. (2009). The efficacy and safety of posterior pole buckles in the control of progressive high myopia. Eye, 23(12), 2169-2174.
- ^ Robyn E. Bradley (September 23, 2003). "ADVOCATES SEE ONLY BENEFITS FROM EYE EXERCISES" (PDF). The Boston Globe (MA). http://visioneducators.com/articles/advocates_see_only_benefits_from_eye_exercises.pdf.
- ^ Rawstron JA, Burley CD, Elder MJ (2005). "A systematic review of the applicability and efficacy of eye exercises". J Pediatr Ophthalmol Strabismus 42 (2): 82–8. PMID 15825744.
- ^ G Rupolo, M Angi, E Sabbadin, S Caucci, E Pilotto, E Racano and C de Bertolini (1997). "Treating myopia with acoustic biofeedback: a prospective study on the evolution of visual acuity and psychological distress". Psychosomatic Medicine 59 (3): 313–317. PMID 9178342.
- ^ Randle RJ (1988). "Responses of myopes to volitional control training of accommodation". Ophthalmic Physiol Opt 8 (3): 333–340. DOI:10.1111/j.1475-1313.1988.tb01063.x. PMID 3269512.
- ^ Gallaway M, Pearls SM, Winkelstein AM, et al. (1987). "Biofeedback training of visual acuity and myopia: A pilot study". Am J Optom Physiol Opt 64 (1): 62–71. PMID 3826280.
- ^ Koslowe KC, Spierer A, Rosner M, et al. (1991). "Evaluation of accommotrac biofeedback training for myopia control". Optom Vis Sci 68 (5): 252–4. PMID 1852394.
- ^ Dunaway D, Berger I. "Worldwide Distribution of Visual Refractive Errors and What to Expect at a Particular Location.". Retrieved August 31, 2006.
- ^ a b Fredrick DR (May 2002). "Myopia". BMJ 324 (7347): 1195–9. DOI:10.1136/bmj.324.7347.1195. PMC 1123161. PMID 12016188. http://bmj.com/cgi/pmidlookup?view=long&pmid=12016188. >
- ^ National Research Council Commission. "Myopia: Prevalence and Progression." Washington, D.C. : National Academy Press, 1989. ISBN 0-309-04081-7
- ^ a b Sperduto RD, Seigel D, Roberts J, Rowland M (March 1983). "Prevalence of myopia in the United States". Arch. Ophthalmol. 101 (3): 405–7. DOI:10.1001/archopht.1983.01040010405011. PMID 6830491.
- ^ http://www.disabled-world.com/disability/types/vision/nearsighted-gene.php
- ^ http://news.xinhuanet.com/politics/2010-01/03/content_12745349.htm Xinhua News Agency
- ^ Chandran S, Comparative study of refractive errors in West Malaysia, J Brit Ophthalmol 1972; 56: 492–495, and
- ^ Wu HM et al. (2001). "Does education explain ethnic differences in myopia prevalence? A population-based study of young adult males in Singapore". Optom Vis Sci 78 (4): 234–239. DOI:10.1097/00006324-200104000-00012. PMID 11349931.
- ^ Mallen EA, Gammoh Y, Al-Bdour M, Sayegh FN (July 2005). "Refractive error and ocular biometry in Jordanian adults". Ophthalmic Physiol Opt 25 (4): 302–9. DOI:10.1111/j.1475-1313.2005.00306.x. PMID 15953114. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0275-5408&date=2005&volume=25&issue=4&spage=302.
- ^ a b c Mavracanas TA, Mandalos A, Peios D, et al. (December 2000). "Prevalence of myopia in a sample of Greek students". Acta Ophthalmol Scand 78 (6): 656–9. DOI:10.1034/j.1600-0420.2000.078006656.x. PMID 11167226. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1395-3907&date=2000&volume=78&issue=6&spage=656.
- ^ Mohan M, Pakrasi S, Zutshi R (1988). "Myopia in India". Acta Ophthalmol Suppl 185: 19–23. PMID 2853533.
- ^ Logan NS, Davies LN, Mallen EA, Gilmartin B (April 2005). "Ametropia and ocular biometry in a U.K. university student population". Optom Vis Sci 82 (4): 261–6. DOI:10.1097/01.OPX.0000159358.71125.95. PMID 15829853. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=1040-5488&volume=82&issue=4&spage=261.
- ^ a b c Kempen JH, Mitchell P, Lee KE, Tielsch JM, Broman AT, Taylor HR, Ikram MK, Congdon NG, O'Colmain BJ (April 2004). "The prevalence of refractive errors among adults in the United States, Western Europe, and Australia". Arch. Ophthalmol. 122 (4): 495–505. DOI:10.1001/archopht.122.4.495. PMID 15078666.
- ^ Vitale S, Sperduto RD, Ferris FL III (2009). "Increased Prevalence of Myopia in the United States Between 1971-1972 and 1999-2004". Arch Ophthalmol 127 (12): 1632–9. DOI:10.1001/archophthalmol.2009.303. PMID 20008719. http://archopht.ama-assn.org/cgi/content/full/127/12/1632.
- ^ a b Kleinstein RN, Jones LA, Hullett S, et al. (August 2003). "Refractive error and ethnicity in children". Arch. Ophthalmol. 121 (8): 1141–7. DOI:10.1001/archopht.121.8.1141. PMID 12912692.
- ^ Wensor M, McCarty CA, Taylor HR (May 1999). "Prevalence and risk factors of myopia in Victoria, Australia". Arch. Ophthalmol. 117 (5): 658–63. PMID 10326965.
- ^ Junghans BM, Crewther SG (2005). "Little evidence for an epidemic of myopia in Australian primary school children over the last 30 years". BMC Ophthalmol 5: 1. DOI:10.1186/1471-2415-5-1. PMC 552307. PMID 15705207. http://www.biomedcentral.com/1471-2415/5/1.
- ^ Thorn F, Cruz AA, Machado AJ, Carvalho RA (April 2005). "Refractive status of indigenous people in the northwestern Amazon region of Brazil". Optom Vis Sci 82 (4): 267–72. DOI:10.1097/01.OPX.0000159371.25986.67. PMID 15829854. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=1040-5488&volume=82&issue=4&spage=267.
- ^ Garcia CA, Oréfice F, Nobre GF, Souza Dde B, Rocha ML, Vianna RN (2005). "[Prevalence of refractive errors in students in Northeastern Brazil."] (in Portuguese). Arq Bras Oftalmol 68 (3): 321–5. DOI:10.1590/S0004-27492005000300009. PMID 16059562. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-27492005000300009&lng=en&nrm=iso&tlng=en.
- ^ Mark Rosenfield, Bernard Gilmartin (1998). Myopia and nearwork. Elsevier Health Sciences. p. 23. ISBN 978-0-7506-3784-8. http://books.google.com/?id=mNT577S8uywC&pg=PA24
- ^ Czepita, D.; Lodygowska, E.; Czepita, M. (2008). "Are children with myopia more intelligent? A literature review". Annales Academiae Medicae Stetinensis 54 (1): 13–16; discussion 16. PMID 19127804. edit
- ^ SL, Beedle; Young FA (1976). "Values, personality, physical characteristics, and refractive error". Am J Optom Physiol Opt. 53 (11): 735–9. PMID 998715. http://www.ncbi.nlm.nih.gov/pubmed/998715.
- ^ Mutti, Donald O.; G. Lynn Mitchell, Melvin L. Moeschberger, Lisa A. Jones, and Karla Zadnik (2002). "Parental Myopia, Near Work, School Achievement, and Children's Refractive Error". Investigative Ophthalmology & Visual Science 43 (12).
- ^ http://pingpong.ki.se/public/pp/public_courses/course05877/published/1291044572089/resourceId/4019767/content/infoweb/node-3216918/Myopia,%20Lifestyle,%20and%20Schooling%20in%20Students.pdf
- ^ Mutti, D. O.; Mitchell, G. L.; Moeschberger, M. L.; Jones, L. A.; Zadnik, K. (2002). "Parental myopia, near work, school achievement, and children's refractive error". Investigative Ophthalmology & Visual Science 43 (12): 3633–3640. PMID 12454029. edit
- ^ David Brooks "Perverse Cosmic Myopia" New York Times March 19, 2009. Retrieved 2011-10-25
- ^ Thompson, Clive (2009-09-17). "Don't Work All the Time". Wired 17 (08). http://www.wired.com/culture/lifestyle/magazine/17-08/by_work. Retrieved 2009-08-14.
- ^ InnerBody: Corrective Lenses - Myopia. Retrieved 2011-10-25
- ^ InnerBody: Corrective Lenses - Hyperopia. Retrieved 2011-10-25
- ^ Jacobi FK, Pusch CM. A decade in search of myopia genes. Front Biosci. 2010 Jan 1;15:359-72.
- ^ Shen W, Vijayan M, Sivak JG. Inducing form-deprivation myopia in fish. Invest Ophthalmol Vis Sci. 2005 May;46(5):1797-803.
- ^ Ji FT, Li Q, Zhu YL, Jiang LQ, Zhou XT, Pan MZ, Qu J. Form deprivation myopia in C57BL/6 mice. Zhonghua Yan Ke Za Zhi. 2009 Nov;45(11):1020-6.
- ^ Tejedor J, de la Villa P. Refractive changes induced by form deprivation in the mouse eye. Invest Ophthalmol Vis Sci. 2003 Jan;44(1):32-6.
- ^ a b Boulamery A, Simon N, Vidal J, Bruguerolle B. Effects of L-Dopa on circadian rhythms of 6-OHDA striatal lesioned rats: a radiotelemetric study. Chronobiol Int. 2010 Jan;27(2):251-64.
- ^ Weiss S, Schaeffel F. Diurnal growth rhythms in the chicken eye: relation to myopia development and retinal dopamine levels. J Comp Physiol A. 1993 Apr;172(3):263-70.
- ^ Xi X, Chu R, Zhou X, Lu Y, Liu X. Retinal dopamine transporter in experimental myopia. Chin Med J (Engl). 2002 Jul;115(7):1027–30.
- ^ McMahon DG, Brown DR. Modulation of gap-junction channel gating at zebrafish retinal electrical synapses. J Neurophysiol 1994;72:2257–68.
- ^ Pendrak K, Nguyen T, Lin T, Capehart C, Zhu X, Stone RA. Retinal dopamine in the recovery from experimental myopia. Curr Eye Res. 1997 Feb;16(2):152-7.
- ^ Fernandez N, Garcia JJ, Diez MJ, Sahagun AM, Díez R, Sierra M. Effects of dietary factors on levodopa pharmacokinetics. Expert Opin Drug Metab Toxicol. 2010 May;6(5):633-42.
- ^ O'Malley KL, Harmon S, Moffat M, Uhland-Smith A, Wong S. The human aromatic L-amino acid decarboxylase gene can be alternatively spliced to generate unique protein isoforms. J Neurochem 1995;65:2409–16.
- ^ Hadjiconstantinou M, Rossetti Z, Silvia C, Krajnc D, Neff NH. Aromatic L-amino acid decarboxylase activity of the rat retina is modulated in vivo by environmental light. J Neurochem 1988;51:1560–4.
- ^ Rossetti ZL, Silvia CP, Krajnc D, Neff NH, Hadjiconstantinou M. Aromatic L-amino acid decarboxylase is modulated by D1 dopamine receptors in rat retina. J Neurochem 1990;54:787–91.
- ^ Rossetti Z, Krajnc D, Neff NH, Hadjiconstantinou M. Modulation of retinal aromatic L-amino acid decarboxylase via alpha 2 adrenoceptors. J Neurochem 1989;52:647–52.
- ^ Leguire LE, Komaromy KL, Nairus TM, Rogers GL. Long-term follow-up of L-dopa treatment in children with amblyopia. J Pediatr Ophthalmol Strabismus. 2002 Nov–Dec;39(6):326-30; quiz 345-6.
- ^ Gao Q, Liu Q, Ma P, Zhong X, Wu J, Ge J. Effects of direct intravitreal dopamine injections on the development of lid-suture induced myopia in rabbits. Graefes Arch Clin Exp Ophthalmol. 2006 Oct;244(10):1329–35. Epub 2006 Mar 21.
- ^ a b Mao J, Liu S, Qin W, Li F, Wu X, Tan Q. Levodopa inhibits the development of form-deprivation myopia in guinea pigs. Optom Vis Sci. 2010 Jan;87(1):53–60.
- ^ Martignoni E, Blandini F, Godi L, Desideri S, Pacchetti C, Mancini F, Nappi G. Peripheral markers of oxidative stress in Parkinson's disease. The role of L-DOPA. Free Radic Biol Med. 1999 Aug;27(3–4):428-37.
- ^ Hattoria N, Wanga M, Taka H, Fujimura T, Yoritaka A, Kubo S, Mochizuki H. Toxic effects of dopamine metabolism in Parkinson's disease. Parkinsonism Relat Disord. 2009 Jan;15 Suppl 1:S35-8.
