Transcript PK group
World Cornea Congress VI April 7-9 Boston Long-term Surgically Induced Astigmatism After Toric Iris-fixated Lens Implantation in Post-keratoplasty and Virgin Eyes Nienke Visser, Tos T.J.M. Berendschot, Rudy M.M.A. Nuijts University Eye Clinic, Academic Hospital Maastricht, the Netherlands The authors have no financial interest in the subject matter of this poster. Purpose To compare the long-term changes in corneal astigmatism induced by toric iris-fixated intraocular lens (IOL) implantation in post-keratoplasty patients and patients with no previous ocular surgery. Methods • Retrospective study • Exclusion criteria: corneal pathologies laser refractive surgery other corneal surgery after Artisan implantation • Groups: 1. no previous ocular surgery (control group) 2. post-keratoplasty (PK group) • Toric iris-fixated IOL (Artisan,Ophtec BV, the Netherlands) • 5.4 mm superior incision Methods: Surgically induced astigmatism (SIA) • Determined by corneal topographies (Eyemap, Alcon, TX, USA): - preop - 6 months postop - 3 years postop • Individual cylinder + axis → Cartesian coordinate (x,y) • SIA calculated by standard vector analysis 1 • SIA displayed in double angle minus cylinder plots: 45° Diopters Example 2 1 90° 2 1 1 1 2 135° 1. Holladay JT et al. Analysis of aggregate surgically induced refractive change, prediction error, and intraocular astigmatism. J Cataract Refract Surg 2001; 27:61-79. 2 0° Diopters Methods: Covariates influencing the SIA • Multivariate linear modelling • Following possible covariates were examined: Control group PK group Age Age Preoperative astigmatism Preoperative astigmatism Incision location (on steep/ flat axis) Incision location (on steep/ flat axis) Time between PK and IOL implantation Indication for PK Results: Preoperative astigmatism Number of eyes Age (years) Preoperative corneal astigmatism Control group Double angle minus cylinder plot, with an ellipse of 1 standard deviation (SD) Control group PK group P value 38 35 46 ± 8 64 ± 15 <0.001 -1.40 ± 1.04 D @ 1 ± 12° -1.19 ± 5.50 D @ 168 ±16° 0.762 PK group Double angle minus cylinder plot, with an ellipse of 1 SD → No significant differences in mean preoperative astigmatism between two groups Results: SIA Control group PK group Double angle minus cylinder plot, with an ellipse of 1SD Double angle minus cylinder plot, with an ellipse of 1 SD Control group PK group SIA at 6 months -0.47 ± 0.53 D @ 88 ± 12° -0.59 ± 2.02 D @ 71 ± 14° 0.606 SIA at 3 years -0.76 ± 0.59 D @ 89 ± 12° -1.29 ± 2.73 D @ 98 ± 15° 0.478 → No significant differences in SIA between the two groups → Variability in SIA much larger in PK group P value Results: Covariates influencing the SIA Control group Control group: The amount of preoperative astigmatism was a covariate significantly influencing the SIA at 3 years postoperatively (p<0.001). PK group This continues variable was categorized in order to demonstrate its influence. Data shown as mean SIA with an ellipse of one SD. PK group: Fuchs’ endothelial dystrophy as the indication for PK was a covariate significantly influencing the SIA at 3 years postoperatively (p=0.026). Data shown as mean SIA with an ellipse of one SD. Conclusion • Toric iris-fixated lens implantation induced a more variable amount of SIA in PK eyes, compared to control eyes. • We recommend to incorporate the expected SIA into the lens power calculation in control and PK eyes. Contact: [email protected]