Comparing surgically induced astigmatism calculated by means of simulated keratometry versus total corneal refractive power



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Garzón Jiménez, Nuria and Rodríguez Vallejo, Manuel and Carmona González, David and Calvo Sanz, Jorge A. and Poyales Galán, Francisco and Palomino Bautista, Carlos and Zato Gómez de Liaño, Miguel Á and Fernández, Joaquín (2018) Comparing surgically induced astigmatism calculated by means of simulated keratometry versus total corneal refractive power. European Journal of Ophthalmology . 9 p.. ISSN 1120-6721 (Unpublished)

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Purpose: To evaluate surgically induced astigmatism as computed by means of either simulated keratometry (KSIM) or total corneal refractive power (TCRP) after temporal incisions.
Methods: Prospective observational study including 36 right eyes undergoing cataract surgery. Astigmatism was measured preoperatively during the 3-month follow-up period using Pentacam. Surgically induced astigmatism was computed considering anterior corneal surface astigmatism at 3mm with KSIM and considering both corneal surfaces with TCRP from 1 to 8mm (TCRP3 for 3mm). The eyes under study were divided into two balanced groups: LOW with KSIM astigmatism <0.90D and HIGH with KSIM astigmatism ≥0.90D. Resulting surgically induced astigmatism values were compared across groups and measuring techniques by means of flattening, steepening, and torque analysis.
Results: Mean surgically induced astigmatism was higher in the HIGH group (0.31D @ 102°) than in the LOW group (0.04 D @ 16°). The temporal incision resulted in a steepening in the HIGH group of 0.15 D @ 90°, as estimated with KSIM, versus 0.28 D @ 90° with TCRP3, but no significant differences were found for the steepening in the LOW group or for the torque in either group. Differences between KSIM- and TCRP3-based surgically induced astigmatism values were negligible in LOW group.
Conclusion: Surgically induced astigmatism was considerably higher in the high-astigmatism group and its value was underestimated with the KSIM approach. Eyes having low astigmatism should not be included for computing the surgically
induced astigmatism because steepening would be underestimated.

Item Type:Article
Uncontrolled Keywords:Astigmatism, Cataract surgery, Posterior cornea, Multifocal intraocular lens, Surgically induced astigmatism
Subjects:Medical sciences > Medicine > Surgery
Medical sciences > Medicine > Ophtalmology
Medical sciences > Optics > Optometry
ID Code:46775
Deposited On:09 Mar 2018 08:44
Last Modified:09 Mar 2018 08:44

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