Clinical Ophthalmology

The effects of higher-order corneal aberrations on lower-order corneal astigmatism have until now been poorly understood. Differences between the corneal astigmatism and the manifest astigmatism have typically, through a process of exclusion, been diagnosed as lenticular astigmatism. Topography-guided ablation, or WaveLight® Contoura, has added another element of uncertainty, with the manifest refraction and the autorefraction often failing to correspond with the astigmatism that results from Contoura processing.

 

In this Thematic Series, the author demonstrates that correcting Contoura processing through the LYRA (Layer Yolked Reduction of Astigmatism) Protocol results in the correction of astigmatism in almost all cases. The Series further demonstrates that treatment on the wrong manifest astigmatism axis can result in loss of effectiveness of astigmatism correction, as well as induction of a new astigmatism on an oblique axis.