The distance between the lenses is for a "standard" person. Generally, this will not be a problem, but if a patient is sensitive or has more closely set eyes, for example, it may pose a problem. Persons buying ready-made sunglasses or reading glasses should hold them up to see if they appear clear. They should also hold the lenses to see an object with straight lines reflected off of the lenses. If the lines don''t appear straight, the lenses may be warped or inferior.Patients may sometimes need a few days to adjust to a new prescription; however, problems should be reported, durasoftcolorscontacts because the glasses may need to be rechecked.contact

(Lenses made from polycarbonate, the same durasoftcolorscontacts type of plastic used for the space shuttle windshield, are about 50 times stronger than other lens materials.) Also, people at risk of receiving electric shock should avoid metal frames.People employed in certain occupations durasoftcolorscontacts may be prohibited from wearing contact, or may be required to wear safety eyewear over the contact. Some occupations, such as construction or auto repair, may require safety lenses and safety frames. Physicians and employers should be consulted for recommendations. Description Eyes are examined by optometrists (O.D.) or by ophthalmologists durasoftcolorscontacts (M.D. or D.O.--doctor of osteopathy). Prescriptions, durasoftcolorscontacts if necessary, are then given to patients for glasses. The glasses are generally made by an optician. A separate lenses-fitting exam is necessary durasoftcolorscontacts if the patient wants contact, because an lenses prescription is not the same as a lenses prescription.

lensesesOver 140 million people in the United States wear durasoftcolorscontacts lenseses. People whose eyes have refractive errors do not see clearly without glasses, because the light emitted from the objects they are observing does not come into focus on their retinas. For people who are farsighted, images come into focus behind the retina; for people who are nearsighted, images come into focus in front of the retina. Lenses work by changing the direction of light so that images come into focus on the retina. The greater the index of refraction of the lens material and the greater the difference in the curvature between the two surfaces of the lens, the greater the change in direction of light that passes through it, and the greater the correction.Lenses can be unifocal, with one correction for all distances, or they can be correct for more than one distance (multifocal). One type of multifocal, the bifocal, has an area of the lens (usually at the bottom) that corrects for nearby objects (about 14 in durasoftcolorscontacts from durasoftcolorscontacts the eyes); the remainder of the lens corrects for distant objects (about 20 ft from the eyes).