Article Text
Abstract
*Correspondence, Jesse Panhtagani: jesse.panthagani@nhs.net
Objective To investigate the factors associated with the disparity between manifest refractive cylinder (MRC) and keratometric astigmatism (KA) in keratoconic eyes to refine the refractive outcomes of toric intraocular lenses in keratoconic cataract surgery.
Methods A retrospective study at Southend University Hospital assessing 145 keratoconic eyes from 75 patients (57 male, 18 female, mean age 27±8.6 years), and comatic aberration of >0.3 µm (defined with Pentacam HR (Oculus, Germany) at a diameter of 6 mm). MRC power was correlated to corneal tomographic variables including higher order aberrations measured using univariate and multivariate regression analysis. Vector difference between KA and MRC was also explored, to detect tomographic variables associated with this disparity. Axis of MRC was compared and correlated to the axis of corneal coma.
Results Both KA and coma showed a significant correlation with the MRC power. The vector difference between KA and MRC is correlated to the KA, posterior keratometric astigmatism and comatic aberration. MRC axis had significant correlation to the axis of coma, with an inverse relationship between MRC axis and coma axis.
Conclusion Corneal comatic aberration is a significant determinant factor of manifest refractive cylinder power and axis and is correlated with the disparity between manifest and keratometric astigmatism found in keratoconic eyes. The effect of higher order aberrations, particularly vertical coma should be considered when planning intraocular procedures for visual rehabilitation.
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