This document specifies a method to determine the refractive index of optical glass with the accuracy within 3 × 10^-5 at the wavelength range from 365 nm to 2 400 nm by using the V-block refractometer method.

While this document can be used for non-glass materials, the user is informed that only optical glass has been considered in the development of this document, and other materials can have issues, which have not been taken into consideration.