my·o·pi·a (M),

short sight

myopia (M)

Refractive condition of the eye in which the images of distant objects are focused in front of the retina when the accommodation is relaxed. Thus distance vision is blurred. In myopia the point conjugate with the retina, that is the far point of the eye, is located at some finite point in front of the eye (Fig. M16). The percentage of myopes in Caucasian populations is about 24-28%, it is much higher among Chinese (70-80%). Syn. nearsight; short sight. See gene-environment interaction; photorefractive keratectomy; orthokeratology; pseudomyopia; lattice degeneration of the retina; Marfan's syndrome; use-abuse theory.
acquired myopia Myopia appearing after infancy, or in adulthood. Almost all myopias are acquired. Those myopias developing in the late teens and adulthood are usually referred to as late-onset myopia (or adult-onset myopia), whereas those occurring earlier are often referred to as early-onset myopia (or juvenile-onset myopia).
myopia control Term used to encompass the various methods aimed at slowing or arresting the progression of myopia. They include bifocals, contact lenses, pharmaceutical agents, incorrect single vision lenses (undercorrection, overcorrection), vision therapy and feedback strategies. None has yet been found to be reliably effective.
degenerative myopia See pathological myopia.
early-onset myopia See acquired myopia.
empty-field myopia See space myopia.
false myopia See spasm of accommodation.
form-deprivation myopia Myopia developing in children when the retina is stimulated by a blurred image during the critical period of development. It may occur as a result of a pathological condition, such as cataract, vitreous haemorrhage, ptosis, eyelid closure, or in inordinately long occlusion therapeutic sessions. See critical period; occlusion therapy.
high myopia Myopias above 6.0 D or more are usually considered as high myopias. See open-angle glaucoma; high index lens; pathological myopia.
hypertonic myopia See spasm of accommodation.
index myopia See lenticular myopia.
instrument myopia A temporary increase in accommodation induced by looking through an optical instrument. See resting state of accommodation.
juvenile-onset myopia; late-onset myopia See acquired myopia.
lenticular myopia Myopia attributed to an increase in the index of refraction of the lens. As a result there is an increase in refractive power. Such a change usually accompanies the development of some cataracts. This type of myopia may also accompany or follow an increase in blood sugar level, in which case it is usually of a transient nature, i.e. the power of the crystalline lens diminishes after the blood sugar level returns to normal. Syn. index myopia. See nuclear cataract; diabetes; micro-spherophakia.
low myopia Myopias of 3.0 D or less are usually considered as low myopias.
malignant myopia See pathological myopia.
medium myopia Myopias between 3.0 and 6.0 D are usually considered as medium myopias.
night myopia An increase in ocular refraction (essentially accommodation) occurring at low levels of illumination. See resting state of accommodation.
pathological myopia Myopia attributed to retinal and choroidal degeneration resulting from excessive elongation of the eye. The myopia usually exceeds 8-10 D, tends to increase rapidly during adolescence and continues to increase during adulthood. Visual acuity is usually subnormal after correction. Pathological myopia is a potential cause of blindness. Syn. degenerative myopia; malignant myopia; progressive myopia. See choroideremia; myopic crescent; macular hole; retinal detachment; sclerochoroiditis; Fuchs' spot; anterior staphyloma; vitreous detachment.
physiological myopia This is the most common type of myopia. It is believed that high myopia is due mainly to genetic factors whereas low myopia is more likely due to environmental influences. It occurs because of a failure in correlation of the refractive power of lens and cornea, and the length of the eye. Thus, the power of the eye is too great for its length. Unlike pathological myopia, this myopia usually stabilizes when the growth process has been completed. It is associated with normal visual acuity after correction. Syn. simple myopia; typical myopia.
progressive myopia See pathological myopia.
senile lenticular myopia See second sight.
simple myopia See physiological myopia.
space myopia An increase in accommodation occurring when viewing a field without any stimuli to accommodation as, for example, a clear sky. Syn. empty-field myopia. See resting state of accommodation.
spurious myopia See spasm of accommodation.
typical myopia See physiological myopia." >Fig. M16 A myopic eye looking at a distant axial point

Table M10 Approximate relationship between uncorrected myopia and visual acuity
		Snellen visual acuity
myopia		(m)		(ft)
−10.0 D		6/600		20/2000
−6.00 D		6/232		20/775
−5.00 D		6/170		50/565
−4.00 D		6/126		20/420
−3.00 D		6/85		20/285
−2.50 D		6/68		20/225
−2.00 D		6/50		20/165
−1.50 D		6/33		20/110
−1.00 D		6/20		20/65
−0.50 D		6/9		20/30

Table M11 Common ocular and systemic diseases with myopia as an associated sign
Marfan's syndrome	retinopathy of prematurity
Ehlers-Danlos syndrome	Stargardt's disease
Down's syndrome	homocystinuria
Cornelia de Lange syndrome	choroideraemia
Weil-Marchesani syndrome	gyrate atrophy
Laurence-Moon-Bardet- Biedl syndrome	rod monochromat
Riley-Day syndrome	ectopia lentis
Turner's syndrome	Fabry's disease
congenital stationary night blindness
Stickler's syndrome	Wagner's syndrome
pigment dispersion syndrome

Patient discussion about short sight

Q. Is there a laser vision correction operation that will correct both near and farsightedness? My optometrist said that typical laservision would require that I wear glasses for reading since it only corrects farsightedness. I'm leery of the technique of doing only one eye for distance and leaving the other "as is" for reading. I seem to recall a brief news report of some new laser vision technique that corrects both near- and farsightedness. Is that true or were they referring to the "one eye for closeup and one eye for distance" type of correction that I'm skeptical about? Thanks!!A. my mother-in-law had that done about a yeara ago,for both near and far,they make them the oppisite,i had my near sightness fixed two years ago and i love it should of done it sooner.....