Lens Thickness Calculator

Enter the lens parameters to calculate the lens thickness.

How to Use

1. Select the lens type (Minus or Plus).
2. Enter the sphere power in diopters. Use negative values for myopia and positive for hyperopia.
3. Select the lens material to get the refractive index. Refer to the table below for common materials.
4. Enter the lens diameter in millimeters. This is often determined by your frame size.
5. Enter the minimum center thickness in millimeters. Standard values range from 1.0 to 2.0 mm.
6. Click on “Calculate Thickness” to see the results.

Lens Type: Minus Lens (Concave) Plus Lens (Convex) Sphere Power (Diopters): Lens Material: CR-39 Plastic (n = 1.498) Crown Glass (n = 1.523) Trivex (n = 1.532) Polycarbonate (n = 1.586) High-Index Plastic (n = 1.60) High-Index Plastic (n = 1.67) High-Index Plastic (n = 1.74) Custom Material

Refractive Index: Material Density (g/cm³): Material Cost ($):

Lens Diameter (mm) (Determined by Frame Size): Minimum Center Thickness (mm): Cylinder Power (Diopters): Axis (Degrees): Calculate Thickness

The thickness of your lenses affects both comfort and appearance. Thinner lenses are lighter and offer better aesthetics. Factors influencing lens thickness include:

• Prescription Strength (Sphere Power): Higher prescriptions typically result in thicker lenses.
• Refractive Index: Materials with higher refractive indices can bend light more efficiently, allowing for thinner lenses.
• Lens Diameter: Larger diameters increase lens thickness. Choosing smaller frames can reduce thickness.
• Lens Design: Aspheric lenses are designed to be thinner and flatter than traditional lenses.

Common Lens Materials and Their Properties

Material	Refractive Index (n)	Advantages	Disadvantages
Crown Glass	1.523	Scratch-resistant, clear optics	Heavy, can shatter
CR-39 Plastic	1.498	Lightweight, inexpensive	Thicker lenses, less durable
Polycarbonate	1.586	Impact-resistant, UV protection	Prone to scratches, optical distortions
Trivex	1.532	Impact-resistant, lightweight	Limited availability
High-Index Plastic (1.60)	1.60	Thinner lenses for moderate prescriptions	More expensive
High-Index Plastic (1.67)	1.67	Even thinner lenses for higher prescriptions	Higher cost
High-Index Plastic (1.74)	1.74	Thinnest lenses available	Most expensive, may reflect more light

Frequently Asked Questions

What is sphere power?

Sphere power measures the degree of nearsightedness or farsightedness in diopters. Negative values indicate myopia, positive values indicate hyperopia.

What is refractive index?

The refractive index indicates how much a lens material bends light. Higher refractive indices allow for thinner lenses.

Why is lens thickness important?

Lens thickness affects comfort, weight, and aesthetics of eyeglasses. Thinner lenses are lighter and look more attractive.

What is the minimum center thickness?

The minimum center thickness ensures the lens meets safety standards for durability and impact resistance.

How can I reduce lens thickness?

Use high-index materials, choose aspheric designs, select smaller frames, and consult with an eye care professional.

What are aspheric lenses?

Aspheric lenses have a more complex surface profile, reducing thickness and improving visual clarity by minimizing distortions.

Does lens diameter affect thickness?

Yes, larger lens diameters increase thickness. Opting for smaller frames can help reduce lens thickness.

Should I consider polycarbonate or Trivex lenses?

They are impact-resistant and ideal for safety, children’s eyewear, or active lifestyles. Trivex offers better optical clarity than polycarbonate.

What is an anti-reflective coating?

An anti-reflective coating reduces glare, improves vision clarity, and enhances the appearance of your lenses by making them nearly invisible.