Refractive index and thickness of the eyeglasses lens

Consumers with glasses, are often very concerned about the fitted look into the mirror after. The factors that determine whether or not the optical appearance is one of the thin and thick lenses. For this reason, many consumers hesitate to spend a little money choose a high refractive index material lenses. The problem is that some of the high refractive index of the lens is not equipped to meet consumer expectations, after the effect of the thickness of the lens material and general seems no significant difference. As a result, business disputes and disputes with the result.

What is a high refractive index of the lens? Refractive index and thickness of the relationship?

Traditional glass lenses, the refractive index of about 1.523 in general. With the scientific and technological progress, there was 1.7, and even the refractive index of 1.8 and 1.9 lenses. Compared with the refractive index of 1.523, 1.7,1.8 and 1.9 of course, known as a high refractive index lenses.

Since the advent of resin lenses, and glass lenses compared with both light and strong impact resistance benefits, consumers will soon get the market share every year. The first CR39 resin lenses, refractive index of only 1.49 or so, and later been found in 1.52,1.62 and 1.67 and other high refractive index lenses. Compared with the refractive index of 1.49, 1.52,1.62 and 1.67, of course they can be called the high refractive index. But if the glass with 1.7,1.8 or 1.9 lenses compared to the only known medium refractive index.

From this, the level of the lens refractive index is a relative term.

Solely from the perspective of the refractive index, high refractive index lens center thickness should be thinner. However, the refractive index is not the only factors that determine the thickness of the lens. Determine the lens material is another important factor is the impact of its own force. Really good lens material can be both light and thin, and impact resistance. Almost the lens material, often by increasing the thickness of the lens center to improve its impact resistance.

Internationally accepted method of impact resistance test lens is drop ball method and extrusion method. Falling ball method is mainly applied to high-quality resin lenses. A fixed weight of the ball free fall from a specific height, hit the center of the lens, and watch his smashed to determine whether the broken lens impact resistance.

Extrusion material for glass lenses or poor resin lenses. Specific approach is to probe a particular round of its load and slowly squeeze the lens, the view of its deformed state.Although a good lens material after compression deformation will occur, but the lens does not crack. Poor compression of the lens material deformation will occur once the crack.

In addition, the ability of UV is an important indicator of assessment of the lens.

From the foregoing, the decision a good or bad quality of the eyeglasses by many factors.Consumers may be able to understand why the brand and non brand lenses lenses between a big price difference.

A regular optical shop, the sales price is determined by its experience with the development of technical content, frames and glasses of the material, whether from formal channels, and quality assurance, whether to provide after-sales service and other factors.The eyes are the most important body organs. Suggest that consumers matching glasses, you should pay full attention to the quality of fitting eyeglasses and performance and price ratio, rather than based solely on price factors to determine the trade-offs.