Ads
related to: are astigmatism glasses more expensiveglassesusa.com has been visited by 100K+ users in the past month
The quality of the glasses was outstanding. - Bizrate
warbyparker.com has been visited by 10K+ users in the past month
GQ Calls it the Netflix of Eyewear - Huffington Post
Search results
Results from the WOW.Com Content Network
Astigmatism (optical systems) An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances. The term comes from the Greek α- (a ...
Progressive lenses are corrective lenses used in eyeglasses to correct presbyopia and other disorders of accommodation. They are characterised by a gradient of increasing lens power, added to the wearer's correction for the other refractive errors. The gradient starts at the wearer's distance prescription at the top of the lens and reaches a ...
People with astigmatism have more difficulty with night driving and can have a decreased productivity due to errors. However, there are many ways to help correct astigmatisms: The use of glasses or contacts, Toric intraocular lenses, Toric implantable Collamer lenses, and/or corneal refractive surgery have been shown to correct astigmatisms.
Since ignition can be achieved even with a poorly made lens, lenses have been used as burning-glasses for at least 2400 years. [6] A modern application is the use of relatively large lenses to concentrate solar energy on relatively small photovoltaic cells, harvesting more energy without the need to use larger and more expensive cells.
Adjustable focus eyeglasses are eyeglasses with an adjustable focal length. They compensate for refractive errors (such as presbyopia) by providing variable focusing, allowing users to adjust them for desired distance or prescription, or both. Current bifocals and progressive lenses are static, in that the user has to change their eye position ...
In glasses with powers beyond ±4.00D, the vertex distance can affect the effective power of the glasses. [4] A shorter vertex distance can expand the field of view, but if the vertex distance is too small, the eyelashes will come into contact with the back of the lens, smudging the lens and causing annoyance for the wearer.
Ads
related to: are astigmatism glasses more expensiveglassesusa.com has been visited by 100K+ users in the past month
The quality of the glasses was outstanding. - Bizrate
warbyparker.com has been visited by 10K+ users in the past month
GQ Calls it the Netflix of Eyewear - Huffington Post