Relation between change of effective lens position and toric IOL rotation after toric IOL implantation

Objective: To evaluate the relationship between change of effective lens position (ELP) and toric intraocular lens (IOL) rotation in patients with increasing postoperative refractive astigmatism after successful toric IOL implantation. Methods: The subjects include 61 people (61 eyes) with increasing residual astigmatism >0.5 D 3 months after successful toric IOL implantation. Clinical measurements included preoperative, 1-week, and 1-, 2-, and 3-month postoperative visual acuity; refraction; keratometer; anterior and posterior corneal astigmatism; ELP by Scheimpflug camera imaging; and IOL axis by slit-lamp biomicroscopic photograph with pupil dilation. Results: Residual astigmatism in postoperative month 3 (0.81 ± 0.50 D) is higher than that at postoperative week 1 (0.41 ± 0.38 D; p < 0.05). ELP decreased by 264.44 ± 163.25 μm, and the IOL rotated by 2.91 ± 1.44 degrees from week 1 to month 3 (p < 0.05). The ELP change had a positive correlation with IOL rotation (R² = 0.383; p = 0.006), and the postoperative refractive astigmatic change had a positive correlation with ELP change (R² = 0.272; p = 0.027) and IOL rotation (R² = 0.272; p = 0.0001) from week 1 to month 3. Conclusion: ELP change can influence toric IOL rotation and increase residual astigmatism after toric IOL implantation.