High-index lenses are an alternative choice to standard, plastic eyeglass lenses. Although high-index lenses are more expensive than plastic lenses, they can reduce the thickness and weight of an eyeglass lens, particularly for individuals with a strong prescription.
High-index lenses are able to bend light to a stronger degree than a lens with a lower index, therefore the higher the index of the lens the less material needed to achieve a given prescription.
High index lenses are categorized according to how strongly they bend light. The higher the index, 1.53 to 1.74 for high-index lenses, the better the lens is at bending light.
High index lenses are 20 percent to 65 percent thinner than standard plastic lenses. In general, the stronger the prescription, the greater the difference in thickness between standard plastic and high-index plastic.
A reduction in lens thickness and weight will occur in high-index lenses for prescriptions stronger than +2.00 or -2.50. Weaker prescriptions are not thinner than standard lenses when made with high-index materials.
Polycarbonate lenses offer the same aesthetic benefits as high-index lenses, but polycarbonate lenses scratch easier, are difficult to coat or tint and are more likely to create distortions in colors and vision.
Standard index 1.5 lenses Standard index 1.5 lenses are the basic CR-39 lenses, come with anti-scratch hard coating, and are shatter-resistant, suitable for spherical power +/- 2.00 or below, and cylindrical power +/- 1.50 or below. Index 1.57 mid index spherical lenses Index 1.57 spherical lenses are with anti-scratch hard coating. This higher index lens greatly reduces the thickness of the lens edge. This is suitable for spherical power of +/- 4.00 or below with cylindrical power +/- 2.00 or below. Index 1.57 mid index aspherical lenses Index 1.57 aspherical lenses are even thinner and lighter than 1.57 spherical lenses. These lenses come with anti-scratch and anti-reflective coating, greatly reducing the image distortion, suitable for spherical power of +/- 4.00 or below, and cylindrical power of +/- 2.00 or below. High index would be anything greater than the 1.57 lenses, like 1.61 or 1.67 and so on. Each having a degree of benefits and drawbacks unique to it's making.
What are the difference's between contour interval and index contour?
Their lenses are adapted to the lesser difference of refractive index between their lens and the surrounding water. Therefore they can see sharper in the water than land animals, which have lenses that are adapted to a dryer lifestyle.
1.57 mid index single vision lenses means that the lens is thinner than standard plastic lenses. It is not the thinnest possible, nor is it impact resistant like Trivex 1.53 mid index lenses, or polycarbonate. It will be thinner than either of those materials. Single vision means that there is one range of vision. If a bifocal lens is not prescribed, then this is what the vision is. When the prescription is a bifocal prescription, then either distance only or reading only must be chosen.
Half of the difference between the two positions is called the "index error".
yes there iis
… by changing the index of reflection
describe the destination index
A glossary defines words, while the index tells what pages certain topics are on in the book.
the contour interval is the difference in elevation between contour lines that are next to each other
index file is organized with the help of any key as index number at rondomly but index sequencial file organized with the help of any index sequentialy rajesh patel
an index shows where a certain word or phrase is in a book, the glossary tells the definition of words in a book.
Index funds are a type of mutual fund that invests in the stocks of a specific market index, attempting to maintain a value per unit that tracks that index.
The refractive index is different.
what the defrent between BMI and IDW
Viscosity is resistance to flow of oil Viscosity Index is a scale to measure viscosity
any type of crime
There are boys and girls. They are different
The index of refraction varies for different colors of light (i.e., for different wavelengths or frequencies), therefore, a source of white light, like rays from the Sun, can get separated into their components. White light isn't "pure" (monochromatic) light - it is really a mixture of many different colors.
It would be the difference between the two darker lines, or index lines, and then divide the space in between with your difference.
the difference between a developed and developing country is the latter has advanced technology , improvrd or modern infrastructure and a higher human development index
HE DIED yesterday have some respect
Language, culture, Human Development Index.
While it is common to find a table of contents at the beginning of the book and an index in the back of the book, actually placement has no bearing on the difference between these two. Contents is a sequential listing of items contained within a publication and an Index is an alphabetical listing. There may be several different forms of Indexes---words found in a publication, Index of Authors, of Articles, of References ... etc. but each Index is an alphabetical listing ... and non-sequential.