The Lowdown about Lenses

Lenses and everything you need to know!

You might think the clinical part of glasses wearing finishes with the end of the eye test and that after that it’s all just about finding the perfect pair of designer frames to flatter your face, but think again!

The type of lenses you chose to have fitted in your glasses can have a significant impact on how well you see in different conditions and how comfortable your glasses are to wear.

In the past, lenses were made of glass and there wasn’t much to differentiate them – technological advances in lens manufacturing mean that there are now lots of options, all designed to offer you different benefits and suitable for different activities and types of frames.

Lett us give you a quick run down!


As we’ve already mentioned, in the past all lenses were made from glass. Although glass lenses can offer exceptional optics, they can also be heavy – particularly in higher prescriptions and can be broken easily, potentially exposing the eye to injury.  For these reasons, glass has fallen out of favour.


In the late 1940s, the first lightweight plastic lenses were introduced in America.  The development was so good that the polymer used (CR-39) is still a popular choice for lenses now.  It’s light weight, good optical qualities and low cost mean that it’s been a firm favourite ever since it’s invention.


The Gentex Corporation introduced the first safety glasses with polycarbonate lenses back in the early 70s. They were originally developed as visors for the Air Force and have been used for various safety applications such as bullet proof glass for banks. Polycarbonate is lighter and more resistant to impact than the CR-39 plastic described above, so has become popular for children’s eyewear, sports and safety glasses.


As recently as 2001, Trivex, a new, an even lighter weight lens material with similar properties to polycarbonate, has been introduced. Impact resistant and offering a better optical experience to some people, this has quickly become established as a firm favourite.

High Index Plastic

If you wear a high prescription, these may be the right lenses for you.  With the properties of polycarbonate in a thinner and lighter lens, this recent development has significantly improved the experience of glasses wearing for some people.

So, there you have it – even though we talk about ‘glasses’ chances are your lenses are made of one of the types of plastics described above.  Our knowledgeable staff can guide you through the selection of lenses suitable for both your prescription and the frame you’ve chosen.

Keep an eye out for a further blog discussing coatings and tints, as these can add a whole additional dimension to your glasses wearing experience.

If you’d like some professional guidance, don’t hesitate to pop into the practice and chat to our expert dispensing team who will be more than happy to help.

You can contact the HBD team online, or by calling our Holborn branch:

HOLBORN – 020 7831 0032