The axial distances in an OCT image are dependent on the refractive index of the material that IVOCT light passes through. As a result, in order to accurately make measurements in images derived from FOR PROCESSING data, the axial dimension of the pixels should be globally corrected by dividing the A-line Pixel Spacing (0052,0014) value (in air) by the Effective Refractive Index (0052,0004) and setting the Refractive Index Applied (0052,003A) to YES. Although not recommended, if A-line Pixel Spacing (0052,0014) is reported in air (i.e., not corrected by dividing by Effective Refractive Index) then the Refractive Index Applied value shall be set to NO.