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: nienke.visser@mumc.nl