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Vector analysis of regular corneal astigmatism correction during cataract surgery by implanting a bitoric IOL
Session Title: Toric IOL Outcomes
Session Date/Time: Monday 07/10/2013 | 16:30-18:30
Paper Time: 17:51
Venue: Auditorium (First Floor)
First Author: : E.Krall AUSTRIA
Co Author(s): : M. Hohensinn E. Arlt J. Alió J. Mendicute G. Grabner A.
Aim of this study was to determine astigmatic changes and postoperative refractive and visual outcomes after implantation of the AT TORBI® 709M toric IOL (Carl Zeiss Meditec AG, Jena, Germany) during routine cataract surgery.
Prospective multicenter interventional case series; 1: Vissum-Instituto de Oftalmológico de Alicante, Spain; 2: Ophthalmology Service, Donostia Hospital, San Sebastiįn, Spain; 3:Department of Ophthalmology, Paracelsus Medical University of Salzburg, Austria
Within a prospective multicenter interventional case series the IOL AT TORBI® 709M was implanted to correct preexisting corneal astigmatism during routine cataract surgery. IOL power calculation was done with the internet-based calculator Z CALC. Pre- and postoperatively corneal state, visual acuity, subjective and objective refraction and corneal radii (using a topographer) were examined in all patients. All patients had postoperative examinations within the first week (visit 1) and 6-12 weeks (visit 2) after surgery. The astigmatic changes were evaluated using Alpins vector method, based on the 3 fundamental vectors target-induced astigmatism (TIA), surgically induced astigmatism (SIA) and difference vector. The various relationships between these 3 vectors were calculated, including flattening effect, torque, magnitude of error, angle of error and correction index, providing complete description of astigmatic correction achieved.
In three centers a total of 84 eyes (71 patients) have been included within this trial. Postoperatively refractive cylinder could be reduced significantly (p<0.05), concurrent with visual improvement.
The magnitude of SIA vector was slightly larger than the magnitude of TIA vector 3 month postoperatively. The mean magnitude of difference vector was 0.74 ± 0.44 D 3 month postoperatively. The mean magnitude of error was 0.04 ± 0.57 D and the correction index was 1.04 ± 0.34 both indicating a minimal overcorrection at 3 month, but remained stable within the follow-up period.
The implantation of the monofocal, aspheric, bitoric IOL AT TORBI® 709M seems to offer a safe and effective procedure for treatment of eyes presenting cataract in combination with pre-existing regular corneal astigmatism. To verify these first short-time results further studies are necessary.