Surgically induced astigmatism based on refractive corneal parameters
First Author: G.Velarde SPAIN
Co Author(s): I. Jiménez-Alfaro P. Perez-Merino
To predict the impact of surgically induced astigmatism with the analysis of different corneal refractive parameters.
Hospital Ruber Juan Bravo, Madrid, Spain
The inclusion criteria was no history of previous corneal surgery or disease which could affect corneal topography or cataract surgery and a follow up at least one month after the intervention. A total of 112 eyes were included in the study (39%, males; 61%, females).The pre- and post-operative measurements include refractive error and corneal topography. The software of the Pentacam allowed the extraction of the elevation points of the corneal surfaces for ray tracing analyisis and the study of the astigmatism vectors in horizontal and vertical components. Refractive and aberrometry astigmatism changes were calculated in agreement with the Alpins method.
There was high correspondence between refractive and aberrometry astigmatism (r=0.987; p<0.001). Pre-operatively, the horizontal and vertical components of the aberrometry astigmatism were -0.3±1.1 D [-4.3, 2 D] and 0.5±0.8 D [-2, 2.5 D], respectively. The surgically induced astigmatism (SIA) was 0.3±0.5 D [-0.8, 1.4 D] and -0.1±0.6 D [-3.3, 1.2 D]. On average, the root-mean square (RMS) of the high-order aberrations (HOAs) was 0.25±0.11 μm [0.1,0.6 μm]. Finally, we found correlation between the HOAs and the SIA (Pearson coefficient correlation; p= 0.021).
The surgically induced astigmatism shows high variability between a normal patient population and is associated with the magnitude of corneal irregularities. The three-dimensional analysis of the corneal surfaces and different refractive corneal parameters (astigmatism and HOAs) might open new avenues to predict the impact of the surgically induced astigmatism.
travel has been funded, fully or partially, by a competing company