myopic astigmatism


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Related to myopic astigmatism: hyperopic astigmatism

astigmatism

 [ah-stig´mah-tizm]
an error of refraction in which a ray of light is not sharply focused on the retina, but is spread over a more or less diffuse area; it is due to differences in curvature in the refractive surfaces (cornea and lens) of the eye. adj., adj astigmat´ic. Its exact cause is not known; some common types of astigmatism seem to run in families and may be inherited. Probably everyone has some astigmatism, since it is rare to find perfectly shaped curves in the cornea and lens, but the defect is rarely serious. If the refractive error is troublesome, corrective lenses may be needed.
compound astigmatism that in which both principal meridians are either hyperopic (compound hyperopic astigmatism, with rays coming into focus behind the retina) or myopic (compound myopic astigmatism, with rays coming into focus in front of the retina).
corneal astigmatism that due to the presence of abnormal curvatures on the anterior or posterior surface of the cornea.
hypermetropic astigmatism hyperopic astigmatism.
hyperopic astigmatism that in which the light rays are brought to a focus behind the retina.
irregular astigmatism that in which the curvature varies in different parts of the same meridian or in which refraction in successive meridians differs irregularly.
lenticular astigmatism astigmatism due to defect of the crystalline lens.
mixed astigmatism that in which one principal meridian is hyperopic and the other myopic.
myopic astigmatism that in which the light rays are brought to a focus in front of the retina.
regular astigmatism that in which the refraction changes gradually in power from one principal meridian of the eye to the other, the two meridians always being at right angles; this condition is further classified as being against the rule when the meridian of greatest refractive power tends toward the horizontal, with the rule when it tends toward the vertical, and oblique when it lies 45 degrees from the horizontal and vertical.

my·o·pic a·stig·ma·tism

that form of astigmatism in which one meridian is myopic and the one at right angle to it is without refractive error.

my·o·pic a·stig·ma·tism

(mī-op'ik ă-stig'mă-tizm)
An astigmatism in which both meridians are myopic.
References in periodicals archive ?
Q-factor customized ablation profile tor the correction of myopic astigmatism.
Q-factor customized ablation profile lor the correction of myopic astigmatism.
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A 20-year-old woman underwent uncomplicated bilateral Wavelight LASIK for treatment of compound myopic astigmatism.
A 52-year-old man underwent bilateral CustomVue LASIK for treatment of compound myopic astigmatism.
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keratectomy for moderate to high myopic astigmatism.
Laser in situ keratomileusis for the correction of myopia and myopic astigmatism.
The treatment of myopic astigmatism on the VISX STAR Excimer Laser System will provide consumers with the first safe, effective, non-invasive alternative to other surgical techniques currently being used for the correction of astigmatism.
NASDAQ/NMS:VISX) announced today that the FDA Ophthalmic Devices Advisory Panel has recommended approval of its Excimer Laser Systems for use in the treatment of low to moderate nearsightedness with myopic astigmatism.
PARK is the correction of myopic astigmatism by use of the excimer laser.