Agreement Between Internal Astigmatism and Posterior Corneal Astigmatism in Pseudophakic Eyes

Internal astigmatism, which is the discrepancy between refractive and keratometric astigmatism, is the element of total ocular astigmatism that is not caused by the anterior corneal surface. The magnitude of internal astigmatism varies between 0.07 and 2.58 diopters (D), with a mean value of 0.79 D, in normal eyes.1 This astigmatism provides a compensatory effect for anterior corneal astigmatism, which is predominantly with-the-rule.2 The contribution of internal astigmatism to refractive astigmatism has been of interest to surgeons desiring to determine the optimal power for the toric

Source: Journal of Refractive Surgery - June 11, 2018 Category: Opthalmology Authors: Sepehr Feizi, MD, MSc Source Type: research