Comparing standard lenses and High index lenses

At 2020glasses all our online prescription glasses come complete with standard 1.5 index plastic CR39 lenses with a scratch resistant coating. Our standard lenses are manufactured by industry leading lens manufacturers.

When do you need to consider Hi Index or thin lenses?

High index lenses are recommended when your eyesight prescription begins to increase and using a standard lens would increase the edge of the lens beyond a cosmetically acceptable appearance.

Hi index lenses reduce the overall thickness of the lens both at the centre and at the edge. Making your glasses look aesthetically more appealing. The overall weight of the glasses reduces leaving you with a great looking pair of spectacles you can be proud of. Here at 2020glasses we are please to offer you high quality high index aspheric lenses.

High index lenses are a great choice when you want your spectacles to be thinner, lighter and as comfortable as possible.

Advantages of Higher Index Lenses

  • Thinner and lighter lenses.
  • The higher the index, the lighter and thinner the lenses become.
  • Improved UV protection over CR39 and glass lenses.
  • Flatter lenses compared to 1.50 index

There are many types of Hi Index lenses. The most common types are 1.6 index 1.67 index and 1.74 index lenses.  Below we can show you a visual comparison of a +/- 6.00 lens.

At the bottom of the image we see how a standard 1.5 index lens would appear and as we scan to the top of the image we see how the same lens power would reduce in thickness and weight when a high index lens is used.

Below is a Table to show High index lens thickness comparisons in percentage terms:

High Index lens Percentage % reduction in thickness and weight compared to a standard 1.5 index lens
1.6 Approximately 30 – 36 % thinner
1.67 Approximately 40 – 45% thinner
1.74 Approximately 48% thinner

Factors apart from your prescription which effect the thickness of your lens are:

  1. The size of the glasses.
  2. Material of the spectacle frames.
  3. Shape of the glasses

Smaller frames will reduce the thickness of your lenses because the excess lens is cut away. Less lens means thinner and lighter glasses.

Plastic or acetate frames have thicker edges; hence the edge of the lens is hidden within the frame.

Oval or round frames often yield thinner lens results, because the central part of the lens is used avoiding the edges.

In any case if you are unsure as to what index of lens to choose below is a small guide to help you:

When should I consider using a High Index lens? See below table

Prescription Suitable lens index
Between 0.00 to +/- 2.50 1.5
Between +/- 2.75 to +/- 3.75 1.6
Between +/- 3.75 to +/-5.00 1.67
Above +/- 5.00 1.74

At 2020glasses we use the highest quality plastic lenses. Glass lenses are seldom used in prescription glasses due to the heavy nature and risk of shattering under low impact conditions.

Plastic lenses therefore need to be coated with special coatings.

Coatings

Hard scratch resistant coating

At 2020glasses we provide many different levels of protective coatings for your glasses. All our standard lenses come with scratch resistant hard coatings as standard.

Over the years we have had to remind customers scratch resistant is not quite the same as scratch proof. It is always imperative to carry your glasses in a protective case and clean them using nonabrasive cleaners. Avoid placing them in pockets or face down on any surface as this will cause damage to your lenses.

 

Anti-reflective coatings

Hard Multi-Coating – HMC

HMC- Hard Multi-Coating prevents reflections to ensure bright, clear vision.

This is a multi-layered combination of multiple coatings given principally to plastic lenses. This coating comprises an antireflection coating, a scratch resistant coating, a top hydrophobic coat to prevent water getting smudged on the surface of the lens and a zirconium oxide coating to increase the lens toughness. This not only enhances the optical performance but also the life of the lens.

You can choose to have an anti-reflective coating on your glasses. If you look at any camera lens it has an anti-reflective coating. Anti-reflective coatings allow light to travel through your lens into your eye reducing unwanted reflections from bouncing of the front and back surface of the lens. An uncoated lens creates much reflection and can cause dazzling effects especially for night driving.

2020glasses recommend you consider having an Anti-reflective coating on your lenses to complete your glasses and let you see with absolute clarity.

Non-Coated Lens Coated Lens

 

Blue light Anti reflective coating

Blue Light AR is an advanced anti reflective coating which limits the ability of blue light which enters the eye. Blue light emission is found to be from digital devices such as computers, phones, and tablets.

This has all the benefits of an anti- reflective coating whilst giving you that added comfort of Blue light AR.

 

Honeycomb lenses

Better Vision, Inspired by Nature

2020glasses always love to bring in innovative technology. Honeycomb lenses are a new innovative lens treatment. Using natures design of the honeycomb it allows more light to be distributed from all areas of the lens improving vision and reducing eye fatigue.

Key benefits of honeycomb lenses:

  • Crisper, sharper vision with optimum clarity
  • Reduced glare in bright light and night time driving conditions
  • Improved eye fatigue
  • Full UVA and UVB protection
  • Scratch resistant
  • Easy to clean
  • Anti-reflective qualities to virtually eliminate reflections on the lens surfaces
  • Super-hydrophobic layer to repel water and oils

Ideal for use when:

Honeycomb lenses can be worn in your everyday glasses; however many find they work best when:

  • Working in artificial or low light conditions
  • Driving at night or in bad weather
  • Reading/writing
  • Working on a computer or tablet

What does it look like?

Honeycomb lenses appear completely clear, but the patented mesh technology is just visible under close inspection or when the lens becomes misted.

 

Tinted sunglass lenses

2020glasses offers you a range of tinted glasses. All our sunglasses come with UV400 protection. All lenses are tinted to sunglass level.  Available in Grey, brown and green.

 

Polarised Lenses

Polarised lenses are advanced sunglasses. Standard tinted lenses whilst they offer protection they still suffer from unwanted glare. Polarised lenses eliminate unwanted glare and block UVA and UVB.  Available in Grey Brown and Green

 

Photochromic lenses (Transitions)

Photochromic lenses are great for the outdoor enthusiast who love the flexibility of wanting clear glasses indoors and tinted glasses outdoors. Photochromic lenses offer protection against UVA and UVB. At 2020glasses we have various brands for you to choose from.  Available in grey or Brown.

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