Toric intraocular lens implantation in cataract patients with corneal opacity

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.

Toric intraocular lenses: Expanding indications and preoperative and surgical considerations to improve outcomes

Since the introduction of the first toric intraocular lens (IOLs) in the early 1990s, these lenses have become the preferred choice for surgeons across the globe to correct corneal astigmatism during cataract surgery. These lenses allow patients to enjoy distortion-free distance vision with excellent outcomes. They also have their own set of challenges. Inappropriate keratometry measurement, underestimating the posterior corneal astigmatism, intraoperative IOL misalignment, postoperative rotation of these lenses, and IOL decentration after YAG-laser capsulotomy may result in residual cylindrical errors and poor uncorrected visual acuity resulting in patient dissatisfaction. This review provides a broad overview of a few important considerations, which include appropriate patient selection, precise biometry, understanding the design and science behind these lenses, knowledge of intraoperative surgical technique with emphasis on how to achieve proper alignment manually and with image-recognition devices, and successful management of postoperative complications.