Glass 1.9 or Plastic 1.74 Double Aspheric, which is the thinnest lens?

Glass 1.9 or Plastic 1.74 Double Aspheric, which is the thinnest lens?

People with strong or complex prescriptions are always looking for the thinnest possible lenses to avoid embarrassingly thick glasses where the lenses either stick out from the side of the frame or bulge in the centre.  Until recently their choice of lenses was limited, but now thanks to the latest advances in thin lens technology they have more than just one option available. 

As well as regular Plastic High Index Lenses, Plastic 1.74 Double Aspheric lenses and Glass 1.9 High Index lenses are also available. In this article we will explain about the various lens options available to help you to decide which lenses will be best for you.

 

Plastic 1.74 Double Aspheric Lenses

Also known as Bi Aspheric Lenses or DA Lenses, Double Aspheric Lenses differ from regular Plastic High Index Lenses, as they are surfaced on both sides of the lens, hence the name Double Aspheric lenses. This makes them significantly flatter and thinner than regular Plastic High Index Lenses which are only surfaced on one side of the lens. This flatter design also helps to reduce optical distortion and improves peripheral vision. For people who are long sighted with a strong plus prescription, they help to reduce the magnification effect of their eyes appearing enlarged when someone is looking directly at them. The opposite applies for people who are short sighted with a strong minus prescription, they reduce effect of their eyes appear smaller than they actually are when someone is looking at them.

Key facts about Double Aspheric Lenses 

  • Double Aspheric Lenses have a thinner and flatter look than standard High Index Lenses. They will give a better result than the equivalent aspheric High Index Plastic Lenses.
  • Double Aspheric Lenses are lightweight and durable, and are suitable for all types of frame including rimless, semi rimless and full rim frames. They are also safe to use for sporting activities. 
  • Double Aspheric Lenses are available for both single vision and varifocal prescriptions. 
  • Double Aspheric Lenses can also be tinted and made into sunglass lenses. 

 

Glass 1.9 High Index Lenses

Glass lenses have been around for a number of years and are the thinnest lens material available. They give excellent visual clarity and are almost impossible to scratch. They are ideal for people who are short-sighted with strong minus prescriptions as Glass 1.9 index lenses will be thinner than any plastic lenses including the new 1.74 DA lenses.

Key facts about Glass High Index Lenses

  • For a strong “-” prescription Glass High Index Lenses will be thinner than any plastic lenses including Double Aspheric Lenses
  • Glass High Index Lenses are more difficult to scratch than plastic lenses
  • Glass High Index Lenses have superior visual clarity compared to plastic lenses   
  • Glass High Index Lenses are available for both single vision and varifocal prescriptions. 
  • Glass lenses are more fragile and slightly heavier (approx. 10 to 12 grams) than plastic lenses
  • Glass lenses cannot be tinted in anyway (so no sunglasses or Transitions)

 

How can you tell which of these lenses will be best for you?

There are pros and cons with both types of lenses but ultimately the lens choice will come down to two factors, your individual prescription and what you use your glasses for. To help you decide there is a general rule of thumb to follow:

If you are short sighted (near) and have a strong “-“ prescription, the thinnest lenses available are Glass 1.9 Index Lenses.

If you are long sighted (far) and have a strong “+“ prescription, the thinnest lenses available are Plastic 1.74 Index Double Aspheric Lenses.

Despite their excellent qualities many High Street opticians still do not stock Glass High Lenses or Double Aspheric Lenses. Those that do tend to charge a substantial premium for them. The good news is that both the Glass 1.9 High Index lenses and the new 1.74 DA lenses are available online, click here for more information. For information on how to choose the right High Index Lenses and frame for your prescription please contact one of our customer service team on 020 8150 3484 or customerservice@thinlenses.co.uk.


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