Measured Corneal Astigmatism Versus Pseudophakic Predicted Refractive Astigmatism in Cataract Surgery Candidates

Toric intraocular lenses: Evidence‐based use

“…These estimates of non-anterior corneal astigmatism are from refraction of eyes with intraocular lenses. 32 Such eyes have known lenticular astigmatism, making calculation of the non-anterior corneal and non-lenticular astigmatism possible, and the measured posterior astigmatism is smaller than the values derived from such a calculation. This implies that the measurement of posterior corneal astigmatism is inaccurate or that there is another 'left-over' astigmatism present derived from other sources-lens tilt or decentration, for instance.…”

“…For the present, the use of measured posterior corneal astigmatism values to derive a total corneal astigmatism for inclusion in toric IOL calculation is less successful in predicting outcome than the application of estimated or outcome-derived values. 31,32 The later methods automatically include the effect of this 'left-over astigmatism'. This may explain their higher success rates.…”

“…Achieving astigmatic refractive outcome of close to 100% of eyes within 1D or less from the target and 90% within 0.5D is possible. 32…”

“…This is acceptable to most patients if the sphere equivalent remaining error is similarly on target. Achieving astigmatic refractive outcome of close to 100% of eyes within 1D or less from the target and 90% within 0.5D is possible 32 …”

“…There is a difference between the measured and estimated effect of posterior corneal astigmatism. These estimates of non‐anterior corneal astigmatism are from refraction of eyes with intraocular lenses 32 . Such eyes have known lenticular astigmatism, making calculation of the non‐anterior corneal and non‐lenticular astigmatism possible, and the measured posterior astigmatism is smaller than the values derived from such a calculation.…”