KEY TAKE-AWAYS
- Posterior corneal astigmatism (PCA) is important in the selection of the toric IOL power
- Not considering PCA results in an overcorrection in eyes with-the-rule (WTR) astigmatism and an undercorrection in eyes with against-the-rule (ATR) astigmatism
- A majority of comparative studies using the Barrett toric IOL calculator are suggesting that the use of predicted and measured PCA does not impact clinical outcomes
- One report showed benefits of utilizing predicted PCA in refractive outcomes of eyes with WTR and ATR astigmatism
- Two reports supported the use of measured PCA in (1) eyes with high PCA of more than 0.8D and (2) a whole group analysis but not in the subgroup analysis of WTR, ATR and oblique eyes
- Reasons for not detecting a clear benefit when applying PCA measurements in the Barrett toric IOL calculator may include: different technologies used for measuring PCA, limited sample size, limitations in technology precision in determining PCA, or presence of a newly found and clinically relevant leftover astigmatism