Glasses do not apply after there are three possibilities:
Optometry inaccurate results or Fake oakleys frogskins sunglasses cheap for sale glasses prescription without conversion;
II, lens installation is not appropriate;
Third, the existence of certain optical defects of the lens.
1) result optometry and glasses prescription
Optometry method is divided into two kinds of subjective and objective. Subjective refraction appropriate for simple refractive, and objective view on all refractive error conditions are suitable. Objective view agent before using the ciliary muscle paralysis, which can cause eye fatigue the muscles to rest, role of ciliary muscle disappeared, Mydriasis, recessive refractive errors become dominant, laid the Foundation for us to arrive at a real result. Especially in patients who do not cooperate, we can directly control their refractive conditions. The optometry inaccurate results due, on the one hand the right way, on the ciliary muscle paralysis agents is not used, the subjective objective of Optometry optometry, Hitomi optometry the Mydriatic refractometry, such as objective refraction results for -4.5DS-1.00DCx180=5.0, subjective refraction results likely to be -5.0DS=5.0, by the opticians, patient discomfort is inevitable.
Glasses prescription is not exactly the same as the view results, it must be the latter on the basis of the appropriate "processing", otherwise the patient may not be able to endure. Anisometropia, difference in degrees to control 3.0D, so as to avoid his eyes ranging eye astigmatism axis converted to Parallels or symmetrical, so as not to lead to distortion; lens degree is higher due to lower, while increasing spherical mirror; high hyperopia glasses to reduce the degree for the first time.
2) lens installation
The tilt of the lens. Eye looking down many opportunities, especially when you're tall and read eye in patients with, and perpendicular to the axis of the lens, there must be a certain degree of tilt, usually 10-150.
Distance between lens and cornea. For determining the effectiveness of Cheap Tiffany and Co Necklace Jewelry Outlet lenses and retinal image size plays a very important role. Theory of 15.7mm, 13-14mm, without touching the eyelashes. Because the lens away from the cornea or near or far, can lead to retinal image to zoom in or out, when the difference in eye diopter is large, the eyes cannot blend cause discomfort.
Improper handling of the optical center of the lens and polarizing, Every deputy has to determine the optical center of the lens, optical Center, and install it properly, otherwise the light entering the eye deviation. 10.0D spherical lenses, optical Center offset 1mm, 1 Prism effect caused by poor inspection interference occurs. Centre for optical and geometric center and do not confuse. In actual work in the, we sometimes will intends to let optical Center deviated from Geometry Center, as with glasses to for not symmetric of faces; lenses due to itself weight or nasal bone low led to glasses fell and will optical Center up offset,, is to better to avoid polarizing heart of occurred, also has artificial to polarizing heart installed sense also this, as near with glasses; correction implicit strabismus or overcome collection force insufficient or had strong Shi. Therefore, heart is light or polarized, pros and cons isn't set in stone, but handled properly there will be trouble.
Pupillary distance measurement determination is incorrect or correct lens installation error, Prism effect may also occur, not repeat them here.
3) lenses is optical defects
This problem cannot be avoided, such as a lens or two refractive distortion caused by cataract lenses, such as narrowing of the Visual field, having ruled out other factors still cannot be completely eliminated, but to let patients get used to. Some can be reduced and even eliminated, if oblique astigmatism question, spherical aberrations, such as zoom, which demands for installation and selection of lenses. It is well known that in order to make eyeball in all aspects of vision are clear to see, we should choose a week depending on the type of lens (base arc 1.25D); the most oblique astigmatism, you choose to Crescent-shaped lenses (base arc 6.0D); when the lens is being installed requires concave near the eye forever, to eliminate the spherical aberration, and ranges in order to prevent, also can choose lenses. In practice, the author has such experience, many after the patients switched to another type of lens, Visual disturbance disappear immediately, although the targets exactly the same two pairs of Cheap Oakleys Radar Sunglasses Discount eyeglasses, so selecting the right model, reducing optical defects of the lens itself to eliminating opticians do not apply after is also important.