1.56 High Definition ASP HMC Green Coating Optical Lens from China Suppliers and Factory for Myopia and Astigmatism Correction
Data
| Product | High Definition lens | Index | 1.553 |
| Material | Resin | Abbe Value | 34 |
| Diameter | 65/70 | Coating | HMC Green coating |
Performance
Anti-fingerprint
Waterproof
High transmittance
Wear resistance
Anti reflection
UV protection
Lens refractive index
It refers to the ratio of the propagation speed of light in vacuum to the propagation speed of light in the lens material.
It reflects the refractive power of the lens towards light.
The higher the refractive index, the stronger the refractive power of the lens towards light.
- For low myopia below 200 degrees, a refractive index of 1.50 or 1.56 can be chosen;
- For myopia between 200-400 degrees, a refractive index of 1.56 or 1.60 can be chosen;
- For myopia between 400-600 degrees, a refractive index of 1.60 or 1.67 is more suitable;
- For high myopia at 600-1000 degrees, it is recommended to choose a refractive index of 1.67 or 1.71.
- For myopia exceeding 1000 degrees, glass lenses with refractive indices of 1.71 or 1.74, or even higher, can be considered.
If you choose a larger frame, in order to ensure that the edges of the lens are not too thick, you may need to choose a slightly higher refractive index.
Assuming all other parameters are the same, the higher the refractive index of the lens, the thinner the edge thickness of the lens, and the lighter the lens.
High refractive index lenses can make the lenses thinner, lighter, and more comfortable to wear.
However, high refractive index lenses are usually more expensive and the dispersion phenomenon may be more pronounced.
With the advancement of material technology, this law is gradually being broken,
For example, the Abbe number of lenses with a refractive index of 1.71 is higher than that of most lenses with a refractive index of 1.56 and 1.67.
Frequently Asked Questions
Q: What is the refractive index of a lens?
The refractive index refers to the ratio of the speed of light in a vacuum to its speed inside the lens material. It measures the lens's ability to bend light. A higher refractive index indicates a stronger light-bending capability.
Q: How does refractive index affect lens thickness and weight?
Assuming all other parameters are identical, lenses with a higher refractive index will have thinner edges and a lighter overall weight, making them more comfortable for daily wear.
Q: Which refractive index is suitable for high myopia (600 to 1000 degrees)?
For high myopia between 600 and 1000 degrees, it is highly recommended to choose a refractive index of 1.67 or 1.71 to keep the lenses thin and lightweight.
Q: Does the size of the glasses frame affect the choice of refractive index?
Yes. Choosing a larger frame typically requires a slightly higher refractive index to prevent the outer edges of the lens from becoming excessively thick.
Q: Are higher refractive index lenses always subject to more dispersion?
Not necessarily. While high refractive index lenses historically had more pronounced dispersion, modern material technology is breaking this pattern. For instance, 1.71 index lenses feature an Abbe number higher than most 1.56 and 1.67 index lenses.