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Evaluation of residual astigmatism after limbal relaxing incision using vector analysis
Session Title: Assessment of Astigmatism
Session Date/Time: Saturday 05/10/2013 | 11:00-12:30
Paper Time: 12:04
Venue: Main Lecture Hall (Ground Floor)
First Author: : J.Wiesinger AUSTRIA
Co Author(s): : N. Hirnschall S. Maedel M. Weber P. Draschl O. Findl
To evaluate the effect of LRIs on the corneal and total astigmatism of the eye.
Vienna Institute for Research in Ocular Surgery, Department of Ophthalmology, Hanusch Hospital, Vienna
This prospective study includes patients who were scheduled for cataract surgery with limbal relaxing incision. Partial coherence interferometry measurements (IOL-Master 500, Carl Zeiss Meditec AG, Germany) were performed pre-operatively and 1 week, 3 months and 1 year post-operatively. Additionally, corneal topography (Atlas model 9000, Carl Zeiss Meditec AG) and viscoelastic properties of the cornea (ORA, Reichert Ophthalmic instruments, USA) were performed pre-operatively, 3 months and 1 year postoperatively. Furthermore, autorefraction (Autorefractometer RM 8800 Topcon, Japan) and subjective refraction were performed at the 1 year follow-up visit.
In total, 80 eyes will be included in this study. Preliminary results showed that the mean corneal astigmatism pre-operatively and 1 week, 3 months and 12 months post-operatively was 1.97D (±0.42; 1.32 to 2.76) and 1.19D (±0.8; 0.29 to 2.88), 1.19 (±0.74; 0.34 to 2.47) and 1.25 (±0.59; 0.57 to 2.61), respectively. Vector differences between pre-operative astigmatism and 1 week, 3 months and 12 months after surgery were 1.40D (±0.49; 0.62 to 2.03; p<0.001), 1.16D (±0.40; 0.38 to 1.75; p<0.001) and 1.09D (±0.44; 0.27 to 1.71; p<0.001). Between the 1 week and the 3 months follow-up the astigmatism reducing effect of the LRI was significantly reduced (p=0.004). Viscoelastic properties and topography measurements will be presented at the meeting in Amsterdam.
LRIs significantly reduce corneal astigmatism, but there is a significant regression of the effect within the first 3 months after surgery.