Selecting the right lenses for your glasses is the most crucial part of buying eyeglasses. The quality of the lenses, coatings, and attributes will go a long way in making you contented with the glasses. While frames are essential for their aesthetics and comfort, lenses are as important since they dictate the safety and vision clarity of the glasses.
With several options in the market today, it can be challenging to settle on the type of lens that suits your eyes and lifestyle. Eye care professionals like Spectera will help you choose the best lenses for your problem.
Here are the top things to put in mind when buying eyeglasses.
1. Visual Needs
Eyeglasses are primarily used to correct different vision problems. So, when choosing lenses, you need to consider their vision-correcting properties. The two main categories here is multifocal or single-vision lenses.
Let’s look at the types of lenses for different visual needs;
- Single Vision Lenses
These lenses typically have an inward curve and are used to correct near-sightedness (myopia) and far-sightedness (hyperopia).
- Bifocal Lenses
They consist of two lenses that correct both myopia and hyperopia. You can clearly see a line dividing the two.
- Progressive Lenses
These lenses correct vision at far, middle and near distances without a visible division or transition zone.
- Trifocal Lenses
It consists of three lenses that correct near and far-sightedness as well as middle-distance focus (presbyopia).
- Prism Lenses
Corrects heterophoria, a condition where eyes look in different directions when at rest.
- Toric Lenses
These single-vision lenses correct astigmatism.
Choosing the right lenses depending on your problem as evaluated by Spectera will go a long way in giving a clearer and undisturbed vision.
2. Lens Material
Lens material and coating customizes your eyeglasses to fit different environments. This can be colour change with the lighting or sun protection. What’s interesting is that some coatings are resistant to scratches! The list below helps you understand the various types of lens material.
- Glass
Glass lenses are of high quality and scratch-resistant, although they’re heavier and have an increased risk of breaking even with slight falls.
- Polycarbonate
This material is lighter and impact resistant.
- CR-39 Plastic
Plastic polymer is thermal-cured to produce lightweight lenses that are also quite affordable.
- High-index Plastic
This material makes the lens lighter and thinner, allowing more light to pass through.
With the above primary materials used to make eyeglass lenses, you can have additional coating features which protect your eyes against several things. These coatings are like;
- Anti-scratch coating
- Colour tint
- Anti-reflective coating
- Gradient tint coating
- UV rays coating
- Light-adjusting
3. Lens Thickness
The centre and edge thickness of the lens determines the vision problem it is going to correct. The shape and size of frames will also dictate the thickness of the lenses. When choosing glasses, go for small and well-centred frames as they will reduce the weight and thickness of the lenses regardless of the material.
4. Abbe Value
This is a measure of the width of light wavelengths dispersion as it goes through the glasses. Low Abbe value means a high distribution, which can lead to coloured halos, especially around lights.
Abbe value of the lens falls between a high of 59 to a low of 30. The lower this number, the higher the chances you’ll experience chromatic aberration.
5. Aspheric Design
Aspheric design, together with refraction index, give your lens a slimmer and more attractive look. Aspheric design refers to the gradual lens curvature from the centre towards the edges.
Manufacturers prefer this design as it guides them to use flatter curves without lowering the lenses optical performance.
Since aspheric lenses are flatter than spherical lenses, user’s eyes will often experience little to no unwanted magnification and clearer peripheral vision.
6. Index of Refraction
Refractive index is a measure of how efficient the lens material bends light. It depends on the speed of light through the material. The lower the refractive index, the faster light travels through it, which means greater refraction.
In simpler terms, lens materials with a high refractive index are usually thinner than those with a low refractive index. While it may sound Greek, experts at Spectera will help you calculate this to find the perfect lens material for your eye problem.
Final Thoughts
Buying eyeglasses is a daunting process. You want to get the best value and maximum benefits from your valuable eyewear. You should get accurate information from reputable sources like Spectera before settling for the right lenses.