What is a mid index lens?
The higher the number, the thinner and lighter the lens. The lower numbers are classified as mid-index lenses. Mid-index lenses, such as 1.54, 1.56, and 1.57, are thinner than glass, and nearly as strong as CR-39. Trivex is an improvement over Polycarbonate.
What are mid and high index lenses?
A higher index means that light travels more slowly through the lens material and more bending of light rays occurs. Because of this, some glass lenses do not require as much lens material as would glass lenses with a lower index. Prescription glasses with a higher lens index will have thinner lenses.
What is 1.56 Mid Index digital free form lenses?
1.56 Mid-Index The 1.56 is 15% thinner than the 1.50 Standard. These work with prescriptions ranging from -3.00 to -3.75 and +3.00 to +3.75. They are recommended for full-rim eyeglass frames and glasses worn when participating in sports. The 1.56 combines great optics with a thin, lightweight design.
What is single vision lens type?
Single vision glasses are designed to help people who require correction of farsightedness, nearsightedness, or astigmatism. These eyeglasses have just a single optical prescription correction and they distribute focus evenly over the entire surface area of the lens. Most people that wear glasses usually get this type.
What is the difference between 1.59 and 1.6 index lenses?
The 1.59 is probably polycarbonate which will be lighter and impact resistant, but does have a little bit of distortion. Versus the 1.6 lens will be more optically clear, but will be heavier and not impact resistant (if that is important for your lifestyle).
What are 1.61 high index lenses?
High-index lenses have good optical clarity, 100% UV protection, and excellent durability. They currently come in indices of 1.61, 1.67, and 1.74. All three lenses are made with similar materials, so the choice of index comes down to your prescription strength. A 1.61 high-index lens is best for +5.00/-7.00 or above.
What does single lens mean?
In short, single vision lenses are glasses lenses that only offer ONE type of vision correction. This means that they are crafted to help people see better at farther or shorter distances (nearsighted or farsightedness), but never both.
What are single vision glasses used for?
Single Vision – Single vision prescription lenses are used to correct a single vision problem such as nearsightedness, farsightedness, astigmatism. They contain the same amount of vision correction throughout the entire lens. In terms of single vision reading glasses, full frame readers are the most common.
What is a 1.57 Mid index lens?
The 1.57 mid index lenses are meant for people with moderately strong prescriptions, and they are thinner and lighter than standard lenses. The lens is a polycarbonate composite made from polycarbonate, other polymers, and resins that keep it thinner and lighter than the standard 1.50 lens.
What does standard 1.5 index lenses mean?
refractive index
A standard index plastic spectacle lens’ refractive index is 1.5. Because higher refractive index lenses reflect about 50% more light that standard index lenses, they are always coated with a multi-anti-reflection coating that will reduce the amount of reflections from the lens surface to less than 1%.
What is a 1.59 index lens?
1.59 index lenses are incredibly resilient, offer UV protection, and are impact resistant. These lenses are made from a unique polycarbonate material and can be tailored to the individual. Coatings such as scratch-resistant or anti-reflective can be applied to 1.59 index lenses for additional security.
What is the difference between mid-index and standard lenses?
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 worn during sports activities are most suitable for this lens index.
What are single vision lenses and Bifocal lenses?
Single vision lenses are the most common type of lens found in prescription eyewear. They feature the same prescription across the entirety of the lens surface and can be tailored for distance, mid-range or close up vision. Bifocal lenses are typically distance lenses that include a distinctively cut semi-circle shaped area for close-range vision.
What are thin and light index lenses?
Thin and Light 1.56 index lenses are up to 15% thinner an lighter compared with our standard 1.5 index lenses, these also include anti-reflective coating, anti-smudge, dust repellent and water repellent treatments as standard. Prescriptions with sphere values from +/-3.00 to +/-3.75.
What is the lens index of prescription glasses?
Prescription glasses with a higher lens index will have thinner lenses. However, prescription glasses with a lower lens index will have thicker lenses. The refractive index of prescription lenses extends from 1.5 standard index to 1.74 high index.