Lens makers’ equation provides a relation between refractive index (n), focal length (f ), and radii of curvature R_{1} and R_{2} for a thin lens.

**Lens makers’ equation**

**Here is the Lens makers’ equation:**

**Significance of Lens Makers’ equation**

For preparing spectacles, it is necessary to grind the glass (or acrylic, etc.) for having the desired radii of curvature. Lens makers’ equation can be used to calculate the radii of curvature for the lens, hence it is called the lens makers’ equation.