Don’t be caught off guard by
posterior corneal astigmatism

  • In Koch et al., anterior corneal measurements underestimated Total Corneal Astigmatism (TCA) by 0.22 D @ 180° and exceeded 0.50 D in 5% of eyes

  • Ignoring posterior corneal astigmatism may yield incorrect estimation of TCA¹

  • Selecting toric IOLs based on anterior corneal measurements alone could lead to overcorrection in eyes that have WTR astigmatism and undercorrection in eyes that have ATR astigmatism¹

    [1] Koch DD, et al. Contribution of posterior corneal astigmatism to Total Corneal Astigmatism. J Cataract Refract Surg. 2012;38:2080-2087.

cassini-eye-2Cassini eliminates post-op surprises by measuring Total Corneal Astigmatism.

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Case Example

OPD Lenstar Cassini TCA
Corneal Astigmatism  1.67 D @ 172º 2.11 D @ 159º 1.51 D @ 163º
Nomogram Adjustment  Add 0.3 D Add 0.3 D Total Corneal Astigmatism
Surgical Correction of Adjustment  Treating 1.97 D Treating 2.41 D Treating 1.51 D



Following a nomogram would have led to a treatment of 2 to 2.5 D astigmatism, and would have resulted in a very unhappy patient

Elizabeth Yeu, MD
Virginia Eye Consultants
Norfolk, VA, USA