Choosing the correct lenses for your frame is important to maximise the comfort and efficiency of your prescription. There are different types of lenses and coatings for different applications. Lens technology is very complicated, but we have tried to simplify it as best we can.
It is strongly advised that you discuss with your optician exactly what you need your glasses for. He/she will then tell you what type of lenses and coatings are best for you.
Below we have listed some information that applies to all prescription lenses.
Single Vision Lenses
For the correction of:
- Short-sightedness, near-sightedness or myopia.
- Long-sightedness , far-sightedness or hypermetropia.
- And/or astigmatism, which occurs when the cornea has an irregular curve.
Bi-Focal, Progressive, Varifocal or Multi-Focal Lenses
for the correction of:
- Presbyopia or age related long sight usually occurs around the age of 45 when people start to experience blurred near vision.
- Glass – very rarely used these days because they are heavy and can break/chip easily.
- Resin – known as CR-39 and made from a plastic polymer which is about 50% lighter than glass.
- Polycarbonate lenses – lighter and significantly more impact-resistant than CR-39. Great for safety glasses and sports glasses.
- High refractive Index lenses – Basically, the higher the refractive index, the thinner/lighter the lens, but the higher the cost.
“Thin” – 1.6 index – “Extra thin” – 1.67 index – “Ultra-thin” – 1.74 index
- All of our lenses are pre-coated with a hard (anti-scratch) coating.
Anti-Reflective (AR) Coating
- These coatings greatly reduce reflections onto lenses that cause a reduction in clarity and contrast (glare). This is very beneficial for night driving and prolonged time spent looking at computer terminals.
- There are two main qualities of coating: Standard AR coating and a greatly improved “Blue Light Filter”
- This coating blocks harmful ultra-violet rays which is associated with age-related eye problems including cataracts and macular degeneration over a long period of time.
Fortunately, almost all high-index and polycarbonate lenses come with 100% UV protection. However, the standard CR-39 lens, due to its construction, does not give the same protection as the high-index lenses.
Photochromic (Transition Lenses)
- These lenses are treated to react to the sun’s UV rays. The stronger the rays the darker the lenses become. Photochromic lenses are available on nearly all types of lenses and come in grey or brown tints.
- Specially treated, fixed tinted lenses, available in grey, brown and green. There lenses are designed to cut out surface glare and are ideal for water and snow sports.