At Noosa Optical, we work with a full range of prescription optical lenses. Importantly, we are an independent Optometrist, so we’re not limited to a narrow range of corporate or retail franchise lenses. So, whether you need a simple lens or a highly complex lens, we’re your lens expert.
Optical lenses aren’t all the same
Optical lenses may all look the same, but every lens is subtly different. Some will work well for you, while others will work okay for someone else. Some optical lenses use today’s cutting edge technology while others use old technology from years gone by. The thing is, even a lens expert like us can’t easily tell the difference without referring to industry lens guides. These guides provide us with detailed information about every lens available to us in Australia.
The common adage “you get what you pay for” is true when it comes to lenses. Firstly, less expensive lenses are mostly basic, mass produced and one-size-fits-all. In contrast, precision optical lenses are individually produced to order. They are produced from higher quality materials that will withstand wear and tear better. Furthermore, they will also be thinner, lighter and clearer to look through.
Types of optical lenses for glasses
Two main categories of optical lens exist. Lenses can be either single vision, or multifocal in design. Most prescription optical lenses are now manufactured from plastic resin. Although we can still access glass prescription lenses, high quality plastic resin is generally more suitable, much lighter weight and doesn’t smash when dropped.
Single Vision Lenses
Single vision, or single focus lenses are a common lens type. Designed to correct one type of vision only, single vision lenses provide a single focal distance. In other words, they will allow you to see at one distance only. For example, up close (reading glasses) or over long distance (driving glasses). Consequently, these lenses are restrictive where multiple vision distances are required. So you can’t drive in reading glasses and driving glasses won’t be great for reading a book.
These lenses are simple to produce and come in a wide range of powers to suit almost any prescription type. The best type of single vision lens is made specifically for the wearer. It will precisely account for your exact prescription, eye movements and position and also the unique differences in your frame of choice.
Multifocal lenses allow multiple focusing distances. Bifocal lenses and progressive addition lenses are the two most common types of multifocal lens. The complexities of multi-tasking means these lenses generally cost more to produce. When you need prescription lenses for both long vision and near vision, a multifocal lens is the most convenient solution. As a result, you may not need to have quite so many pairs of glasses as one pair of glasses will achieve more.
The latest and most sophisticated progressive lens designs deliver more seamless and natural vision. As a result, we prefer to prescribe these designs. Progressive Lenses are made with two or three target focal points that gradually and smoothly change throughout the lens. This allows you to achieve natural vision up close, at arms length and at long distance.
Extended Near Lenses
Also know as vocational lenses or office lenses, extended near vision lenses are designed to help you read both up-close and at arm’s length, such as on the computer screen. This eliminates the need to constantly remove, or swap glasses to focus on objects at different distances. They are ideal in an indoor of office situation and can be tailored to match your specific environment, visual tasks and ergonomics.
Bifocal Lenses are similar to progressive lenses except there is no gradual transition, there is a line on the lens. So, two separate focal powers are produced by splitting the lens into two distinct and fixed parts. Today progressive lenses have largely replaced bifocal lenses. The use of technology means almost everyone now works with multiple and varying focus distances.
The optics of prescription glasses lenses
Different manufacturers use different techniques to generate a prescription lens. When it comes to optical precision, you get what you pay for. A precision lens optimises the prescription over a greater area, rather than just the center of the lens. This makes a difference to your peripheral vision and the level of vision comfort provided by the lens.
Optical lens index
The index of a lens determines the thickness and weight of a lens. Generally speaking, the higher the index, the thinner and therefore the lighter the lens. In contrast, a hi-index glass lens may be super thin, but it will be comparatively heavier (and more breakable). So, it’s not as straightforward as choosing the highest index.
Furthermore, different resin types can have the same index number, but have different:
- clarity factor (Abbe number)
- crack resistance
- bending resistance
- chipping resistance
- UV light resistance
- chemical resistance (e.g. metho and acetone)
- heat resistance
We’ll prescribe a lens index that matches your prescription, frame choice and lifestyle needs. We won’t compromise on lens qualities that will place your eyes or glasses at risk.
Abbe value defines lens clarity. This is the lens feature that determines the optical quality of the lens. It’s also the feature that chain stores and discount lens makers don’t talk about. The Abbe number refers to the degree of chromatic aberration (light scatter) caused by a lens material. The higher the number, the better the quality of the lens material. In our view, a large number of lenses available to consumers have an unacceptable Abbe number. We prescribe lenses with high Abbe numbers because this translates to better vision.
Lens finishes and coatings
Lens options including photochromatic (change colour), anti-reflective, tinting and polarising technology will enhance your visual performance and the look of your lenses. Good quality lenses will have lens treatments automatically built into them. Cheaper lenses won’t and you’ll have to pay extra to have them added on.
Tinting a prescription optical lens has come a long way. You can choose from a wide range of colours and include a polarising filter for added glare reduction.
Commonly referred to as “Transitions”, these lenses react to light and/or UV by changing from clear to dark and back to clear again. This allows for a smooth transition from indoors to outdoors without the need to change from spectacles into sunglasses.
Multicoated lenses have undergone a number of finishing treatments. It depends on the manufacturer, but multicoated lens will include at least an anti-reflective coating and a hard coating. Better multi coats are thicker, have more layers and include additional features like UV protection, dust replence, hydrophobic and oleophobic layers. A good multi coat will also last longer.
Anti-reflective treatments improve the visual performance, comfort and look of your lenses by reducing unwanted glare and reflection.
Scratch resistant coatings
Automatically applied to all our lenses at no extra cost, this improves durability. So lenses are less likely to become scratched. There are vast differences in the level of scratch protection provided by different coatings. No lens is completely scratch proof. To prevent scratches, a little care is still required.
UV coatings are automatically built into all of our lenses at no extra cost. So you will get 100% UV protection.
Easy clean coatings
A bit like a teflon pan, they help to repel dirt, water and oil. So your lenses require less frequent cleaning and are easier to clean.
Optical lenses are complex!
The lenses are arguably the most important part of your glasses, and they are the most complex part. Invest in a precision optical lens and your eyes will be happy.
Need more information? Visit us today!