Controls: Index and dispersion variation in optical glass
Related Terms: Homogeneity, bubble grade, striae grade, stress birefrigence, international code, 6-digit code
Units: Dimensionless
Specification Must Contain: Nominal value and linear tolerance (Dispersion tolerance typically given a percentage)
Optimax Preferred Specification: Nd and Vd
Reasons: Correlates with international code, information widely available
Manufacturing Standards: MIL-G-174, ISO 10110-4, OEOSC OP3.001-2001