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glasses of poor quality are likely to cause astigmatism

from:e.uuuwell.com  2017-3-21 04:10

   

now available in many shapes new glasses, you can know the quality of these glasses it? poor glasses to bring great harm to children will affect the axial astigmatism, amblyopia nose developmental and therapeutic effect on young people will affect the progress of myopia, while adults will also affect the appearance and cause visual fatigue.

in general, bad glasses unlicensed production plant from the ground, poorly equipped, low cost, the price is particularly low. in terms of lens material, bad glasses resin matrix impurities, which can cause visual distortion or dizziness. dispersion effect large, prone to cause visual fatigue. adverse stress inside presence, impact resistance is poor, friable. low light transmittance, light distribution uniform. the refractive index of not up to standard its propaganda, exaggerating the extent of the lens thin. in addition, you can not only prevent a small amount of uv or ultraviolet light.

meanwhile, the lens surface treatment, surface treatment inferior good, hard defense without adding flowers function. poor coating technology, easy stripping. mainly the film, antireflection capacity, and no water, pollution, fog and other special features.

in terms of frame materials, bad glasses metal smelting process is poor, low purity, containing impurities, and may even contain harmful radioactive elements to the head, a large proportion of the strong role of the nose oppression, is not conducive to nose section development of young children. poor flexibility, brittle and easily broken. surface gloss and color difference, poor corrosion resistance, rust, and easy to change. there is also great for skin irritation, prone to cause allergies, soft, easy deformation.

for the frame process, he also pointed out that bad glasses rough surface, color gray. poor plating technology, easy to bleaching. poor welding technology, solder is not strong, easy desoldering. hinges and threaded easily damaged.

bad glasses on the assembly also less than the national quality standards. binocular lens optical center one high and one low, left or right, ipd is not accurate, not accurate axial astigmatism, will result in inappropriate prism effect, affecting the normal visual function.

optometric knowledge

1, first of all, must be approved by more assured medical units to check whether the eye disease.

2, refraction lens case, glasses shop focimeter are all basic and necessary measuring instruments, which must be approved by the national legal metrology institutes certified by and within the validity of test results before normal use. otherwise, there is no accurate measuring instruments value this premise, optometrist optometry will be difficult to obtain accurate data, the quality of the assembly out of the optical shop glasses will also be difficult to be guaranteed.

3, consumers should actively cooperate with the optometrist optometry in accordance with relevant procedures, should not experience light to determine the parameters related to prescription based on their experience or estimates, do not arbitrarily change requires experienced optometrists optometry prescription determined or require any glasses store by themselves determine the technical parameters set with glasses.

4, computer refractor optometry with its comfortable, fast, easy, intuitive display, etc. and much people welcome. many consumers also tend to have a computer optometry machine is judged as a grade level optician important factor, in fact, this judgment is not comprehensive. in fact, the computer is only optometry optometry only as a reference method, whereby not directly issued by the optometry prescription, but can not use the results of optometry machine print output directly instead of optometry prescription. must follow to obtain reference data and then make a subjective type of specimen examination computer optometry optometry. in the end, the optometrist will consider each factor is given a suitable optometry prescription.

optometry prescription glasses quantitative accuracy is given premise and condition of acceptable quality, the lack of this factor, the quality of the question set with glasses. therefore, in this sense, the importance of optometry prescription and no less accurate given the importance of the quality of glasses.

5, is an essential part of the frames set with glasses. selected frames, ipd are factors to be considered first, followed in order to consider the individual's face, frame style, color, material, weight and other factors. of course, as the average consumer is concerned, after all, not the choice of knowledge about the spectacle frame and consider it very comprehensive, it accepts the guidance of specialists in store glasses and try them.

6, eyeglass lenses is the core set of glasses of constituent. optical resin lenses are another popular lens is used, it has a high visible light transmittance, low specific gravity, good impact resistance, the use of safety features. consumers do not have a plastic lens and there are any concerns, rest assured to use, because it is after all an optical resin is not an ordinary optical plastic material, but the index of refraction, optical homogeneity, dispersion, transmission performance characteristics to meet the requirements etc. lens material. it is particularly suitable for young children.

7, the problem of glass lens thickness and weight are also more concerned about consumer, generally want the thinner the lens, the more light is better. but after all the important parameters and optical thickness values, appearance and mechanical strength have a relationship of thickness values ​​such as too small, it is difficult to ensure the mechanical strength of the lens and at least safe to use. therefore, the lens is not as thin as possible, consumers do not require the use of unlimited thickness values ​​of small lenses.

8, for the assembled set with glasses, should be properly checked assembly quality under glasses: between the lens and the lens ring no obvious gaps, the lens should not be loose; the left and right lens surface remain relatively flat ; two mirror legs zhang kaiping put even remain flat or inverted shape, frames, etc. without distortion phenomenon. for half-frame (no bottom frame) glasses, should pay attention to thread no abrasions or broken phenomenon, the same line hole location. for frameless glasses should be noted that edge quality, screw fastening, screw cap is not damaged and the like. should also understand some of the glasses use common sense: do as general convex lens down directly on the table or other surface roughness of the surface, in order to avoid accidental scratches and wear lenses; glasses to take with both hands, in order to avoid mirror frame deformation and damage; wearing glasses should be to keep the correct position, not to fall style glasses on his face, as much as possible to reduce the pupil and the lens optical center position in the vertical direction of the difference between each other; loosen the screws should be timely tightened to avoid unnecessary lens shedding problem.

9, glasses glasses store voucher is valid credentials show characteristics of glasses shops glasses are assembled. first, it shows that the assembly of the spectacles store behavior recognition. can doubt that in the future when there is quality, rely on technical supervision or other relevant administrative departments to properly help them solve the problem, once again, but optometry and optician after all, two separate programs, optometry optometry prescription only credentials, and can not represent issued the optometry prescription glasses store certain activities carried out. therefore, consumers must be careful not to replace prescription glasses credentials. finally, it should be noted the request by the optometrist vision be reviewed on a regular basis, when relevant parameters optometry prescription changes, should be replaced right lenses or glasses.