The incision required for IOL implantation during cataract surgery induces astigmatism, which is called surgically induced astigmatism (SIA). The BigSIA application allows you to calculate the induced corneal astigmatism.
It is important to take into account that changing optotype size is not the same that correcting vergence by proximal distance. This is a concept that generates confusion as we have seen in many of the courses we have conducted about Defocus Curves.
In this article we will explain the lens preparation procedure to be carried out before starting to measure a Defocus Curve, in general with any test, and in particular with the Multifocal Lens Analyzer PRO (MLA).