Types of Lens Materials
1.5 Standard Index
Individuals with a weak prescription who want to save money on lenses may opt for a 1.5 standard index lens. This type of lens is suitable for prescriptions with an SPH correction of +/- 2.25 and less, or a CYL correction of +/- 1.50 and less.
1.56 Mid-Index (Thin & Light)
The difference between 1.56 mid-index and 1.50 standard lenses is thinness. Lenses with this index reduce lens thickness by 15 percent. Full-rim eyewear frames and glasses are worn during sports activities are most suitable for this lens index.
Individuals with a somewhat stronger eye prescription may be interested in this type of lens. 1.57 thin & light index lenses are thinner and more durable. Prescriptions for these lenses include an SPH correction between +/- 5.00 and +/- 4.00 and a CYL correction of +/- 3.00 and less.
Polycarbonate lenses offer complete UV protection. The unique polycarbonate material makes lenses stronger and impact-resistant.
With these lenses, individuals can choose lens coatings, such as scratch-resistant or anti-reflective coating, to make up for any possible color differences or add further protection.
1.61 High Index
For those looking for a more modern look, 1.61 high-index lenses may just fit the bill. These ultra-thin lenses are suitable for relatively thin eyewear frames or prescriptions that have an SPH correction between +/- 4.25 and +/- 6.75, and a CYL correction between +/- 2.25 and +/- 3.00.
1.67 High Index
1.67 high-index lenses surpass in thinness and lightness when compared to 1.61 high-index lenses. It helps with eye distortion caused by stronger prescriptions and is ideal for individuals with an SPH correction between +/- 7.00 and +/- 9.00, and a CYL correction between +/- 3.25 and +/- 4.00.
1.74 High Index
Prescriptions in need of the highest lens power may find favor with this type of lens. 1.74 high-index lenses are suitable for individuals with a prescription of an SPH correction of +/- 9.25 and more, and a CYL correction between +/- 4.25 and +/- 6.00.
There are various types of lens materials and they're used depending on the degree of correction needed. These include 1.56 Standard Index, 1.57 Mid-index, 1.59 Thin & Light Index, 1.59 Polycarbonate, 1.61 High Index, 1.67 High Index, and 1.74 High Index.
It is always best to speak with an optician to determine whether you need high-index lenses for your prescription.
Individuals with a relatively strong prescription may find high-index lenses ideal for vision correction. Other additional reasons that may influence the need for high-index lenses include:
- Possibility with semi-rimless or rimless frames
- Reduction of the “coke bottle” effect caused by thicker lenses
However, individuals whose daily life includes strenuous labor or contact sports may find that other, more durable lenses are better suited.
What is the Difference Between 1.57 and 1.61 Index Lenses?
The main difference between 1.57 and 1.61 index lenses is the thickness of the lens material. An individual’s prescription lens power may also influence which type of lens to use for eyewear.
For example, if the lens power is approximately -2.00, it may be more suitable to opt for 1.56 index lenses. The thickness is around 3mm. If the lens power is approximately -4.00, it may be more suited to opt for 1.61 index lenses. The thickness is around 3mm to 4mm.
What Lens Index Is Best for You?
It is best to speak with your eye doctor first to determine the best lens index. They can assess your case and provide you with a prescription that is suitable for your needs.
While high-index lenses are popular nowadays, specific refractive errors or daily lifestyle habits may make another lens index a better option.
Undergoing an eye examination will be the first step to correcting your vision and improving your overall eye health.
An optician is the best person who will help you determine the right lens index depending on your needs. You will first need to undergo a thorough eye exam, so you get the correct prescription according to the results of your exam.