Sunglasses and the real reason we should wear them.Written by Timothy Gorman
Although majority of nations people wear sunglasses for fashion reasons, sunglasses were invented to serve as protection for eyes against UV Rays produced by natural sunlight.
There are three different types of Ultra Violet Radiation. The first is UVC rays. These rays are mostly absorbed by upper atmosphere and show us no reason to be concerned with them. Next are UVA rays. The human eye directly absorbs UVA rays, however, there seems to be little or no evidence that these rays cause any type of eye disorders. The last of ultra Violet Rays is UVB rays and they are most dangerous rays that cause damage to eyes. Studies conducted by Sunglass Association show that people who wear sunglasses on a regular basis, were less likely to have cataracts later on in life. When choosing a pair of sunglasses, make sure that they indicate on them that they protect from ultra violet rays. Sunglasses can provide 100% of Ultra Violet protection that a person needs. If there is any question about level of protection that your sunglasses offer, take them to your optometrist and they can put them on a machine that will tell how much Ultra violet rays can be absorbed from your sunglasses.
Different types of prescription eyeglassesWritten by Timothy Gorman
Prescription eyeglasses are glasses that have been prescribed by an optometrist to be worn by someone who has been diagnosed with a certain eye condition. Depending on condition, a different lens will be prescribed.
Prescription eyeglasses are broken down into four different categories.
The Single Vision Lens has same focal power from top of lens to bottom of lens. People who have been diagnosed as farsighted, nearsighted or with having astigmatism can wear single vision lenses to correct these types of eye disorders. Astigmatism is a condition that doesn't allow light to reflect on retina, thus causing distorted images.
A Bifocal Lens is used to correct a condition call Presbyopia. This disorder usually occurs in people in their late 40's. If a person has been diagnosed with Presbyopia, they can't focus in on close objects. That is where Bifocal Lens is helpful. The top of lens is used for distant vision and bottom of lens is helpful with close vision. People with Presbyopia need both types of Focal View on their prescription eyeglasses.