When buying lenses online, it's important to understand lens index, which refers to how efficiently a lens material bends (refracts) light.

Here are the most commonly used multiple types of indexes to look for:

1.56 Index (Mid-Index Plastic)

Slightly thinner and more durable than 1.50, this lens type works well for prescriptions between ±2.00 and ±3.00. It offers a good balance between cost and performance for everyday use.

1.59 Index (Polycarbonate)
These lenses are impact-resistant and lightweight, making them a great choice for children, sports use, or safety glasses. Ideal for prescriptions up to ±4.00, they also offer built-in UV protection.

1.61 Index (High-Index Plastic)
Thinner and lighter than polycarbonate, 1.61 index lenses are suitable for moderate prescriptions (±3.00 to ±5.00). They provide a more aesthetically pleasing, slimmer look and are recommended for rimless or semi-rimless frames.

1.67 Index (Ultra High-Index)

Designed for higher prescriptions (±4.00 to ±8.00), these lenses are significantly thinner and lighter than lower-index options. They reduce lens bulge and edge thickness, making them more attractive and comfortable for strong prescriptions.

1.74 Index (Super High-Index)

The thinnest and lightest option available, 1.74 index lenses are ideal for very high prescriptions (above ±8.00). They provide the slimmest profile and best comfort without compromising optical quality.