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