1. Nienke Visser, Tos T.J.M. Berendschot, Rudy M.M.A. Nuijts
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.

2. 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.

3. 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

4. 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:
Example
45°
Diopters 2 1
90° 0° 2 1 1 2
Diopters 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.

5. Methods: Covariates influencing the SIA
Multivariate linear modelling
Following possible covariates were examined:
Control group
PK group
Age
Preoperative astigmatism
Incision location (on steep/ flat axis)
Time between PK and IOL implantation
Indication for PK

6. Results: Preoperative astigmatism
Control group
PK group
P value
Number of eyes 38 35
Age (years)
46 ± 8
64 ± 15
<0.001
Preoperative corneal astigmatism
-1.40 ± ± 12°
-1.19 ± ±16°
0.762
Control group
PK group
Double angle minus cylinder plot, with an ellipse of 1 standard deviation (SD)
Double angle minus cylinder plot, with an ellipse of 1 SD
→ No significant differences in mean preoperative astigmatism between two groups

7. 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
P value
SIA at 6 months
-0.47 ± ± 12°
-0.59 ± ± 14°
0.606
SIA at 3 years
-0.76 ± ± 12°
-1.29 ± ± 15°
0.478
→ No significant differences in SIA between the two groups
→ Variability in SIA much larger in PK group

8. Results: Covariates influencing the SIA
Control group:
The amount of preoperative astigmatism was a covariate significantly influencing the SIA at 3 years postoperatively (p<0.001).
Control group
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.

9. 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: