KEY TAKE-AWAYS:

Today’s SS-OCT Biometers employ two methods to measure the axial length: Sum-of Segments using individual refractive indices or a Mean Group Refractive Index

The differences in axial length measurement between the two methods are statistically significant and most noticeable in long and short eyes

Axial length determined with the Mean Group Refractive Index is slightly shorter in short eyes and longer in long eyes

Depending on the length of the eye, some newer IOL power calculation formulas may provide better outcomes with the Sum-of-Segment method