The authors have no financial interest in the subject matter of this poster.
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Long-term Surgically Induced Astigmatism After Toric Iris-fixated Lens Long-term Surgically Induced Astigmatism After Toric Iris-fixated Lens
Implantation in Post-keratoplasty and Virgin EyesImplantation in Post-keratoplasty and Virgin Eyes
The authors have no financial interest in the subject matter of this poster.
Nienke Visser, Tos T.J.M. Berendschot, Rudy M.M.A. Nuijts
University Eye Clinic, Academic Hospital Maastricht, the Netherlands
World Cornea Congress VI World Cornea Congress VI April 7-9 BostonApril 7-9 Boston
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
• 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:
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.
45°
0°90°
135°
Example
1
2
Diopters
Diopters
Methods: Surgically induced astigmatism (SIA)
11 12 2
2
• 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
Methods: Covariates influencing the SIA
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 ± 1.04 D @ 1 ± 12° -1.19 ± 5.50 D @ 168 ±16° 0.762
PK groupControl group
→ No significant differences in mean preoperative astigmatism between two groups
Double angle minus cylinder plot, with an ellipse of 1 standard deviation (SD)
Double angle minus cylinder plot, with an ellipse of 1 SD
Results: SIA
→ No significant differences in SIA between the two groups
→ Variability in SIA much larger in PK group
Control group PK group P value
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
PK groupControl group
Double angle minus cylinder plot, with an ellipse of 1SD Double angle minus cylinder plot, with an ellipse of 1 SD
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
PK group:
Fuchs’ endothelial dystrophy as the indication for PK was a covariate significantly influencing the SIA at 3
years postoperatively (p=0.026).
This continues variable was categorized in order to demonstrate its influence. Data shown as mean SIA with an ellipse of one SD.
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]