How Can You Tell if Your Glasses Have High-Index Lenses?

In summary, the speaker recently purchased glasses from a privately owned optic store and requested hi-index lenses. However, the lenses they received are thicker than expected. They are wondering if there are other ways to determine if the lenses are high-index or plain regular, and also mention seeing "rings" on the edge when looking parallel to the surface. One possible explanation for the thickness is if the front surface is flat, as some plastic lenses only have one curved surface. The speaker also mentions difficulty finding technical information about high-index eyeglass material, with some ads claiming n = 1.70 or 1.74 but without sufficient quantitative information.
  • #1
driedupfish
27
0
Recently, I purchased a pair of glasses from a privately owned optic store. I specifically asked for hi-index lens (1.56 or 1.60, I am not sure). The lens I got, however, is kind of thick (around 5 mm thick on the edges).My eye -sight is poor though, -5.00 sphere, -1.25 cylinder on the worst eye. Are there ways to tell if the lens is high-index or just plain regular lens, besides the thickness? Also, there are "rings" on the edge when I look parallel to the surface of the lens.
 
Science news on Phys.org
  • #2
one reason the lens could be thicker than you expect is if the front surface is flat- some plastic lenses only have one curved surface. This increases the thickness.

I was not able to easily find any technical information about "high index" eyeglass material. I found a few ads claiming n =1.70 or 1.74, but without quantitiatvie information it's hard to separate fact from fantasy.
 
  • #3


I cannot provide a definitive answer without examining the lens myself. However, I can provide some information about high-index vs. regular lenses that may help you determine the type of lens you have.

High-index lenses are made from materials that have a higher refractive index, meaning they bend light more efficiently than regular lenses. This allows them to be thinner and lighter than regular lenses, making them a popular choice for people with high prescriptions like yours.

One way to determine if your lens is high-index is to look for markings on the lens itself. High-index lenses typically have a number, such as 1.56 or 1.60, imprinted on them to indicate their refractive index.

Another way to tell is by comparing the thickness of your lens to that of a regular lens with the same prescription. High-index lenses should be noticeably thinner and lighter.

The "rings" you are seeing on the edge of your lens may be a result of the manufacturing process and not necessarily an indicator of the type of lens. However, if you are concerned, I recommend consulting with your optometrist or the store where you purchased the glasses for clarification.

In conclusion, while there are some ways to determine if your lens is high-index or regular, the best way to know for sure is to consult with a professional. Your optometrist or the store where you purchased the glasses should be able to provide you with more information about the specific lens you have.
 

Related to How Can You Tell if Your Glasses Have High-Index Lenses?

1. What is the difference between high-index and regular lenses?

High-index lenses are made from a material that allows them to be thinner and lighter than regular lenses. They also have a higher refractive index, which means they can bend light more efficiently, resulting in clearer vision. Regular lenses, on the other hand, are made from standard plastic materials and have a lower refractive index.

2. Are high-index lenses more expensive than regular lenses?

Yes, high-index lenses are typically more expensive than regular lenses due to the advanced materials and manufacturing processes used to make them.

3. Do high-index lenses provide better vision than regular lenses?

While high-index lenses can provide clearer vision due to their ability to bend light more efficiently, the difference may not be noticeable for all individuals. It ultimately depends on the individual's prescription and their specific visual needs.

4. Can high-index lenses be used for all types of prescriptions?

Yes, high-index lenses can be used for most types of prescriptions, including those for nearsightedness, farsightedness, and astigmatism. However, they may not be suitable for very strong prescriptions, as the lenses may become too thick and heavy.

5. Are there any downsides to using high-index lenses?

One potential downside to high-index lenses is their increased cost. They may also be more prone to scratching compared to regular lenses. Additionally, some individuals may experience a slight distortion of peripheral vision with high-index lenses, but this can often be corrected with proper lens fitting.

Hot Threads

Recent Insights

Back
Top