How astigmatism to optical correction

Astigmatism is a refraction of the eye is not normal conditions, related to the curvature of the cornea. The human eye is not perfect, if the cornea more curved in a certain angle in radians, while others relatively flat angle, the light will not be accurately focused on the retina, in which case it is called astigmatism.

Ordinary glasses can correct rule astigmatism:

Ordinary glasses can correct rule astigmatism, irregular astigmatism can not use it to correct, and the best way is the use of rigid contact lenses to correct, to good effect. Ordinary lens correction rule astigmatism effect is not the same, the greater the degree of astigmatism worse the effect of mild to moderate astigmatism can generally be corrected to normal, and a high degree of astigmatism correction is more difficult to good effect.

The astigmatic not is corrected will develop into moderate myopically:

High hypertrophy, astigmatism, far and near vision can not see the objects dependent regulation if not corrected as soon as possible, the development of visual function in early childhood will be some inhibition, grew up with Fake Oakleys glasses before until corrected visual acuity worse tend to form moderate myopically. Highly myopic astigmatism, although the look is far from clear, but near vision is also better visual function may also get some exercise is not completely suppressed, corrected visual acuity is generally better than the highly hypertrophy astigmatism. Whatever high astigmatism, corrected the sooner the better. Because the error corrected early, not only to promote the development of visual function, and deformation of objects and spatial orientation reaction to a small degree, the patient can withstand.

Astigmatism prescription glasses according to the following principles to give:

General hyperopic astigmatism less than +0.5 D, 90-degree axial myopia and astigmatism less than-0.5D axial at 180 degrees (the cornea by the oppression of the upper and lower eyelids, the degree of curvature of the cornea to the vertical direction than the horizontal radial the vertical radial refractive power, horizontal weak refraction) generally do not affect vision, can not correction; visual fatigue or affect vision, astigmatism should be corrected to the mirror.

Premise eliminate symptoms or do not affect vision, astigmatism should be low corrosively particularly high degree of astigmatism, astigmatic axis tilt in the direction, should be low corrosively, found that the shape of the object or to see things due to the full correction patients changes and the size of this case, hypertrophy astigmatism change than myopic astigmatism.

Within 3.00D axis myopic astigmatism, adolescents and isotropic should be given to correct. The individual oblique axis with different axis based on the ability to adapt appropriate by many more. Than 3.00D axis hypertrophy astigmatism, Fake Oakley Sunglasses, juveniles and isotropic who should be appropriately reduced by 0.50 ~ 1.00D; the individual oblique axis or hard-axis recipients, should be cut some, wearing glasses after 3 to 6 months in increase should be cut more hypertrophy astigmatism. Oblique axis, different axis degrees on the high, although the degree of reduction trials of patients, the symptoms are mild, but the prescription should be talking to customers to understand the phenomenon of deformation of objects and spatial error will undergo wear, wearing some time 'all adapt.

Under normal circumstances, if the spherical 1.00 ~ 3.00D, astigmatism 0.25 ~ 0.50D; spherical 3.25 ~ 6.00D, astigmatism 0.50D; spherical 6.25 to 8.00D, astigmatism 0.75D; ball 10.00D more astigmatism 1.00D column-plus vision to promote small and ignore the fatigue, you can not mirror column; appropriate given a certain degree of the cylinder, where the column more than value. Some patients with poor sensitivity can be difficult to distinguish Axial given close to the axial shaft. In summary astigmatism of the mirror: mild astigmatism, asymptomatic without astigmatism, have symptoms should wear full correction of astigmatism increase; highly astigmatism, wearing glasses for the first time to be appropriate, to reduce the glasses, to be then used to completely corrected; 2.00D following a simple astigmatism can be fully corrected, 2.00D more simple astigmatism can be divided into secondary correction; complex astigmatism where spherical in 3.00D cylinder 0.50D or less spherical in 6.00 above D, astigmatism 0.75D or more, or spherical in more than 10.00D cylinder 1.00D, where vision enhance required plus astigmatism correction.

If a patient is first wearing Replica Oakley Sunglasses, and high degree of astigmatism, if not meet, according to the ball column equivalents rules to reduce astigmatism, the so-called ball column equivalents rules: add 1/4 of the original column diapers spherical As a new spherical, 1/2 of the original column diapers constant as the axial direction of the rod lens. Example:-1.00DS to-6.00DC of * 90d, patients wear discomfort, the ball column equivalent of rules can be used to do the following changes:-2.50DS to-3.00DC * 90d.