Learn About High Index Lenses

High index lenses are designed for individuals with high prescriptions, including those with nearsightedness (myopia), farsightedness (hyperopia), or astigmatism. Unlike conventional lenses, high index lenses are made from materials that bend light more efficiently, allowing for thinner and lighter lenses.

What is lens index ?

The lens index, also known as the refractive index, is a measure of how much a lens material can bend or refract light. It is a crucial factor in determining the thickness and weight of eyeglass lenses. The higher the refractive index, the more efficiently the lens can bend light, allowing for thinner and lighter lenses, especially for people with stronger prescriptions.

In simpler terms:

A higher lens index means the material can bend light more, resulting in thinner lenses.
A lower lens index means the material bends light less, leading to thicker lenses.
Common lens index values include 1.50, 1.56, 1.60, 1.67, and 1.74. Each of these values represents a different level of thinness, with higher index numbers indicating thinner lenses.

When choosing lenses, your optometrist will consider your prescription strength and recommend a lens index that balances optical performance, aesthetics, and comfort. Individuals with higher prescriptions often benefit more from lenses with higher refractive indices to achieve thinner and lighter glasses. However, the choice of lens index can also depend on personal preferences and budget considerations.

Is High Index eyeglass lenses are right for you?

These lenses are perfect for the followings

• People with higher prescription above +/-2.00
• who wants thinner lens instead of thicker lens
• when normal index lens distorts the vision

Difference between normal index and high index lenses

1. Material Density:

• Normal Index Lenses: These lenses are made from standard optical materials like CR-39 plastic or glass. They have a moderate material density, which means they can be thicker for higher prescriptions.
• High Index Lenses: High index lenses are crafted from materials with a higher density, enabling them to bend light more efficiently. This property allows these lenses to be thinner and lighter than normal index lenses for the same prescription strength.

2. Thickness:

• Normal Index Lenses: As prescriptions get stronger, the lenses tend to become thicker. This can result in a “bug-eye” appearance for individuals with high prescriptions.
• High Index Lenses: The primary advantage of high index lenses is that they significantly reduce lens thickness for stronger prescriptions. This is particularly beneficial for aesthetic reasons and can provide a more natural look when wearing glasses.

3. Weight:

• Normal Index Lenses: Traditional lenses can be relatively heavy, especially for those with strong prescriptions. This weight can cause discomfort, particularly during extended wear.
• High Index Lenses: High index lenses are substantially lighter due to their reduced thickness. This makes them a more comfortable option for individuals who prefer lightweight eyewear.

4. Aesthetics:

• Normal Index Lenses: Thicker lenses, especially in strong prescriptions, can affect the appearance of the eyes and the overall look of the glasses.
• High Index Lenses: Thinner and lighter lenses create a more aesthetically pleasing appearance. The reduction in lens thickness allows for a more natural look when wearing glasses.

5. Cost:

• Normal Index Lenses: Generally, normal index lenses are more budget-friendly compared to high index lenses.
• High Index Lenses: High index lenses can be more expensive due to the advanced materials used and the benefits they offer, such as reduced thickness and weight.

6. Prescription Strength:

• Normal Index Lenses: Suitable for individuals with mild to moderate prescriptions.
• High Index Lenses: Especially beneficial for those with high prescriptions, as they allow for thinner and lighter lenses without sacrificing optical performance.

In summary, the main difference lies in the material density and the resulting thickness and weight of the lenses. High index lenses excel in providing a more comfortable and aesthetically pleasing solution for individuals with stronger prescriptions. The choice between normal index and high index lenses depends on factors such as prescription strength, budget, and personal preferences.

High index lens price in Nepal

The price of high index lens varies with company . If you are looking for local lens you can get upto 1.67 index which will cost you around Rs 3000-Rs 3500. In branded you can get upto 1.74 index which generally cost above Rs 20000

Does Eyemart Nepal sells High index lenses ?

Yes at Eyemart Nepal you wiil get both local and branded high index lenses . Our optometrist will guide you on choosing high index lenses.