WHAT ARE SINGLE VISION LENSES?
Single vision lenses have just one prescription power across the whole lens. They are a solution for refractive errors such as myopia (near-sightedness) or hypermetropia (long-sightedness). If you only need lenses for one type of vision, you will likely be advised to wear single vision lenses.
Single vision lenses will provide clear vision for seeing things close up or far away, depending on your prescription. Single vision lenses for near-sightedness are usually slightly thicker at the edges, while single lenses for far-sightedness are slightly thicker at the centre of the lens. Whatever your prescription, Ardor single vision lenses are designed to meet your needs perfectly.
How to choose the right lenses index for your glasses
Common eyeglasses lenses can be classified into glass lens, resin lens, special lens and space lens, and the 1.50, 1.53 1.60, 1.67 and 1.74 labelled on lenses are their refractive indexes.
What's index lens?
The refractive index of the lens indicates the efficiency of lens material on bending or refracting light. A higher refractive index indicates that light is more bended and spends more time on passing through the lens. Also, a higher refractive index can deal with higher prescription glasses. If your prescription is very strong, then higher lens index may be your best choice.
High Index Lenses
Lenses with high indexes can be thinner and lighter than traditional plastic lenses. Compared with traditional lenses, highly index lenses can bend the light more efficiently, so they can be thinner while maintaining the same correction power.
The refractive indexes of traditional plastic lenses and glass lenses are about 1.5 and 1.52 respectively. Any lens material with a refractive index higher than these numbers are considered a highly index lens material.
How to Choose the Right Glasses Lens
Differences among different lens indexes can generate great impacts. Thicker lenses are more affordable, but they can only handle lower vision correction demand. Thinner lenses are lighter and more fashionable, but the price is also higher. They can satisfy various vision correction demands, including higher prescriptions. This guidance will teach you how to read the prescription.
1.5 Index Lens – Standard lens
If you are looking for a more cost-efficient lens with a weak prescription, these lenses may be your correct answer. Lenses with this index can deal with prescriptions with an SPH correction of +/- 2.25 and lower or a CYL correction of +/- 1.50 and lower.
1.53 Index Lens
Lenses with this index are made from special polycarbonate materials. This means that they can provide 100% UV protection. They are more durable and resistant to shock, which make them an ideal choice for most people.
These lenses are thinner and stronger than lenses with a 1.5 index and can deal with prescriptions with an SPH correction of +/- 2.25 and lower or a CYL correction of +/- 1.50 and lower
1.6 Index Lens
These fashionable ultra-thin lenses are ideal for strong prescriptions or very thin eyeglasses frame. These lenses are suitable for prescriptions with an SPH correction between +/- 2.50 and +/- 5.00 and a CYL correction between +/- 2.00 and lower
1.67 Index Lens
These lighter and thinner lenses can avoid distortion of eyes due to stronger prescriptions. If you have a very strong prescription, this may be your best choice. We usually recommend that these lenses are applicable to prescriptions with an SPH correction between +/- 5.00 and +/- 7.00 and a CYL correction between +/- 2.25 and +/- 4.00.
1.74 Index Lens
Our thinnest lenses are designed for prescriptions with the highest power. These lenses are applicable to prescriptions with an SPH correction of +/- 7.00 and above and a CYL correction between +/- 3.00 and +/- 6.00.
Although lenses with high refractive indexes are thinner than traditional lenses, their final thickness still depends on your prescription and some other factors, including: your Pupillary Distance(How to Measure Your PD(Pupillary Distance) ), shape of the glasses frame, correction power, astigmatism power and axis, spherical or aspherical lenses.