Lenses are all the same! Aren’t they?

James Brooks examining a lens after surfacing

Why are lenses so expensive? They’re just bits of plastic, aren’t they?

These are questions we are often asked. The simple answer is no, lenses are not all the same. In this blog we will try our best to explain the difference between the many different types of lenses.

Different types of lenses: Digital, HD, and stock.

Have you ever wondered how your spectacle lenses are made? Advanced technologies can be used to make lenses in two main ways.
  1. Pre-manufactured Lenses
  2. Custom Manufactured Lenses

Pre-manufactured Lenses

These types of lenses also commonly known as “Stock” lenses are manufactured to a standard prescription and all lenses made to that prescription in that way are exactly the same. Once manufactured the lenses are polished. These lenses are pre-manufactured with a certain base curve, prescription and blank size. Lenses can then be coated with anti-glare, anti-scratch or both, and packaged for glazing into a frame. Once the lens is finished, optical or optometry retailers will offer these lenses for customers based on their visual needs.

Custom Manufactured Lenses

A surfaced lens is created by taking a blank piece of plastic (without any prescription) and grinding the prescription into the plastic. These lenses are custom made and are manufactured with a custom base curve, prescription and blank size.  Digital lenses utilise state-of-the-art technology to enhance quality and performance. In our digital lenses, we use camber technology to create a single vision lens that delivers superior clarity and performance. With 1/100th diopter precision, this technology allows for ultra-clear vision with minimal edge distortion. Free form lenses provide the absolute best optical quality of any digital lens. A revolutionary digital manufacturing process, Free Form uses computer-aided design and surfacing to produce high-quality, customised lenses providing the viewer with an unsurpassed visual experience.  

Just like a HD TV

Remember the first time you saw high-definition television. Do you recall how your old analog TV picture seemed pixelated and blurry? With high-definition, you can see more detail and colours appear brighter, shapes are sharper, and everything is in sharp focus. Just imagine how your glasses would feel in that situation. With your current lenses, you can probably see fine, much like watching analogue TV was fine, but what if you could see in high-definition? Try our free form digital lenses if you are looking for a better clarity of vision. Just imagine how your HD TV screen will look then! Pre-manufactured Lenses Benefits:
  • Ideal for single vision prescriptions (SPH: +3.75 to -6.00 & CYL: 0.00 to  -2.00)
  • Turnaround times that are faster (convenience)
  • The least expensive (affordable)
Negatives:
  • Size restrictions for prescriptions and blanks
  • A lens with average optical quality due to internal stress
  • After manufacturing, different parts of the lens  harden at different rates, resulting in minor vision distortions. Especially noticeable for certain prescriptions and  eye sensitivity.
  • Measures OC/seg height, pantoscopic tilt, wrap angle, and back vertex distance aren’t taken into account

Custom Manufactured Lenses

Benefits:
  • With this method, we can create almost any prescription (high SPH, CYL, ADD, Prism, etc.)
  • Have a better optical quality, since they are not subject to internal stress
  • Custom prescriptions with base curves and OC/seg heights
  • Adaptable to any frame shape with wrap for less distortion (any size blank can be made)
Negatives:
  • Custom lenses cost more, but they are well worth the extra cost due to improved visual performance

Free Form HD Lenses

Advantages:
  • Night and low light vision is exceptional with free-form lenses. Some sources of light at night, like headlights, can cause glare and halo effects.
  • Exceptional contrast perception: Freeform lenses enhance vision
  • Exceptional colour vision: By optimizing the optics inside your lenses, you’re able to enjoy brighter, more intense colors
  • With this method, we can create almost any prescription (high SPH, CYL, ADD, Prism, etc.)
  • The optical quality of these lenses is better than stock ones because they are not stressed internally
  • Custom prescriptions with base curves and OC/seg heights
  • Prescriptions based on eyewear measurements, like pantoscopic tilt, wrapping, and back vertex distance
  • Adaptable to any frame shape with wrap for less distortion (any size blank can be made)
Negatives:
  • There is an additional cost for these high definition lenses because they were custom made, but it is definitely worth it
The stock lens is like an off-the-rail suit, the digital/surfaced lens is like getting a tailored suit, and freeform lenses are like buying a suit in your size. We offer all of these lens options to our customers, and we want to educate you about the various types of lenses that are available.

A multi-award-winning approach

So successful has Allegro Optical been in helping clients to achieve optimum quality of vision that in 2020 we were awarded the SME News West Yorkshire’s Most Trusted Family Run Eye Care Clinic. In 2019 we scooped no less than five national and regional awards. These awards include National ‘Best New Arts & Entertainment Business of the Yearat a gala event in London. Managing Director Sheryl Doe was awarded the 2019 ‘Dispensing Optician of the Yearand the company has been featured in many national publications including The Times 4BarsRest, The British Bandsman and Music Teacher Magazine. Sheryl has recently been named as a judge in this years SME National Business Awards Are you struggling with your vision? If so call us at either Greenfield on 01457 353100 or Meltham on 01484 907090.

The dangers of mascara

Halloween, Bonfire night, Christmas, New Years – there’s so much going on during this time of year, and it’s filled with parties, meals out, and

Read More »