Single Vision lenses are the standard eyeglass prescription.
These glasses have only one viewing area throughout
the entire lens and the correctional area
can be for far distance, mid distance or reading.
A bifocal lens refers to a lens with two focal points.
A small part of the lens is reserved for myopia correction,
and the rest of the lens is usually distance correction.
Generally, when focusing on a further point,
you will look up and through the long-distance part of the lens, and when working at a close distance,
you will look down and through the bifocal part of the lens.
Close range search for that 'sweet spot' of clear vision.
Described as the wearing experience closest to natural vision.
More than a defined near and distance correction in one lens.
Smooth transition from distance through intermediate to near.
Constant graduation of prescription allows easy sight shifting.
Lens index is a number that describes how thick or thin your lenses are. The higher a lens' index is, the thinner it becomes.
Higher prescriptions require higher index lenses, while lower prescriptions require lower index lenses.
The difference in refractive index of the lens will affect the function and price.
The lower the refractive index, the thicker the thickness.
Of course, the price is cheaper, but it can only meet the requirements of low vision correction.
The higher the refractive index, the thinner the lens and the higher the price, which can meet a variety of vision correction needs.
Suitable for Low prescriptions of SPH (0 to +/-2.0) and CYL (0 to +/-1.5). If your prescription is higher, then you need to upgrade to a high refractive index lens
Most suitable for Low prescriptions of SPH (0 to +/-2.0) and CYL (0 to +/-1.5).
Suitable Low-to-moderate prescriptions of SPH (+/-2.0 to +/-4.0) and CYL (+/-1.5 to +/-2.0).
Thin & Light lenses offer the best value for people who have moderate prescriptions and want a light lens. It is suitable for prescriptions of SPH(+/-4.0 to +/-6.0 ),CYL(+/-2.25 to +/-3.0).
These lenses are great for people with moderate-to-high prescriptions. And are recommended of prescriptions of SPH (+/-6.0 to +/-9.0), CYL (+/-3.25 to +/-4.0) for the best results.
This specification is the thinnest and lightest prescription lenses. Suitable for prescriptions of SPH above +/-9.0,CYL above +/-4.25.