312013Jul

10-point guide to prescription glasses lenses

When it comes to buying prescription eyewear, there are many decisions to make. Will you want stylish Silhouette glasses, or the lightweight elegance of Lindberg? Or can you get rimless prescription glasses for a more minimalist look?

But even more important than the frames are the lenses themselves. This article explains 10 common types of lenses and features in prescription glasses, so you can have an informed discussion with your optometrist about your eyewear needs.

1. Single Vision Stock Lenses

These are prescription lenses used for patients that need correction for either distance or near vision. The optical focal power or prescription is the same over the entire lens, which makes them ideal for lower prescriptions. Stock lenses are pre-made and straight off the shelf, which cuts down the time and cost involved in their production. Stock lenses are limited to the following powers:

  • Minus: zero to -3.50D
  • Plus: zero to +2.75D
  • Cylinder (Astigmatsm) zero to -2.00D

2. Single Vision Grind Lenses

Like single vision stock, grind lenses have one focal length over the entire lens. However they are custom made for the patient’s prescription, making them suitable for people with higher prescriptions. Grind lenses are effective with different types of spectacle frames, especially semi-rimless or rimless prescription glasses.

3. High-Index

High-Index describes a category of plastic lens material that is lighter and thinner than standard (CR39) plastic, enabling people with stronger prescriptions to achieve a more aesthetically pleasing look. The higher the index, the thinner and lighter the lens.

UV protection is also inherent in High-Index plastic lenses.

High-Index levels include:

  • 1.53
  • 1.55
  • 1.59
  • 1.60
  • 1.67
  • 1.70
  • 1.74 (known as Ultra High-Index)

4. Transitions Lenses

These everyday lenses change colour when exposed to UV light, providing optimal balance between outdoor darkness, indoor clarity and speed of activation. Suitable for both children and adults, they are perfect for those with a heightened sensitivity to light. Transitions lenses work with virtually all prescriptions in single vision, progressive and bifocal designs and materials.

5. Bifocal Lenses

Bifocal lenses provide clear vision at two viewing distances, distance and near, with has a visual line separating the viewing zones. As a very old design, bifocals are do not provide intermediate (computer) vision.

6. Multifocal Lenses

Also called progressive or graduated lenses, multifocal lenses are the modern-day replacement for bifocals. As people approach the ages of 40 and 50, their near vision begins to deteriorate, causing problems with tasks such as reading, sewing and other close work.

While single vision reading lenses will give people clear vision up-close, distant objects like the television will be blurry. Multifocal lenses provide the ideal solution: they cosmetically look exactly like single vision lenses, yet they allow wearers to see clearly at close, intermediate and long distances.

It usually takes a short while to adapt to multifocal lenses, but the long-term advantages are significant. The easiest way to adjust to them is point your nose where you are looking.

7. Extended Readers

Extended readers are a type of near multifocal lens that provides a large intermediate and reading zone with less distance vision. This option delivers significant benefits and flexibility for people who work in an office environment or spend time on a computer. This lens can be used all day at the office, but is not recommended for driving.

8. Anti-reflective or Multi-coating

This is a multi-layer protective coating on both surfaces of the lens, which enhances visual performance, comfort, and appearance. Glare from computer screens, overhead lights and night driving can cause eyestrain. Anti-reflective coatings alleviate discomfort by reducing unwanted glare and reflection, allowing the eye to see in precise detail.

9. UV Coating

Regular plastic spectacle lenses block the majority of UV light, but with UV coating, you can boost this protection to 100%. This is not required for polycarbonate lenses and other high index plastic lenses as they already have built-in 100% UV protection.

10. Blue Control

Blue Control is a coating added to prescription lenses that neutralises blue light to prevent eye fatigue and eye strain. This keeps the eyes in better condition whilst offering more comfortable and relaxed vision.

From early morning to late at night, people use all kinds of blue light-emitting digital devices, such as computers, smart phones, tablets, and television screens. A small amount of blue light is present in daylight and helps keep people awake, but excessive amounts can have an adverse effect and cause:

  • Eye strain and fatigue
  • Red and irritated eyes
  • Blurry vision
  • Back, neck and shoulder pain
  • Headaches

For the best prescription lenses, visit Insight Optometrists next to Indooroopilly Shopping Centre

At Insight Optometrists, you know you will be getting the perfect prescription eyewear for your needs. When you combine our highly regarded optometrist Dr Jan Coetzee, our extensive range of designer frames, and our highly trained staff to help you choose the perfect frame and lense comination, you can be assured of glasses that meet your vision needs and make you look fantastic. For more information contact our office next to Indooroopilly Shopping Centre on (07) 3878 2655.