Rotational stability and refractive outcomes of a new hydrophobic acrylic toric intraocular lens

Abstract

Purpose: To assess rotational stability and refractive outcomes of a new toric hydrophobic acrylic intraocular lens (IOL).

Design: Single-center, prospective, interventional clinical trial.

Methods: A total of 130 eyes of 82 patients with age-related cataract and total corneal astigmatism of greater than 1.0 diopters (D) received a hydrophobic acrylic toric IOL Clareon CNW0T3-9. Baseline measurement for rotational stability evaluation was performed at the end of surgery (EOS), with the patient still supine on the operating table, using non-movable vessels as reference landmarks. Postoperative retroillumination pictures were taken at 1 h, 1 week, 1 month and 4-6 months postoperatively. Subjective manifest refraction was assessed at the 6 months follow-up visit.

Results: Final results were obtained in 126 eyes of 80 patients. Mean absolute rotation from EOS to 6 months was 1.33 ± 2.00 [0.01, 19.80] degrees. Rotational stability values from EOS to 1 h, 1 h to 1 week, 1 week to 1 month and 1 month to 6 months were 0.86 ± 0.82 [0.00, 3.90], 1.06 ± 1.94 [0.00, 19.45], 0.47 ± 0.42 [0.00, 2.03] and 0.38 ± 0.40 [0.00, 2.56] degrees. Mean preoperative corneal astigmatism was 1.78 ± 0.83 [1.00, 4.76] D which changed to a mean postoperative refractive astigmatism of 0.33 ± 0.27 [0.00, 1.25] D at 6 months.

Conclusion: The Clareon toric IOL presented very good rotational stability with a mean absolute rotation below 1.4° from EOS to 6 months. Only two IOLs rotated more than 5° with none of them requiring repositioning surgery. Refractive outcomes were satisfying with a mean residual refractive astigmatism below 0.50 D.

Trial registration: Registered at Clinicaltrials.gov NCT03803852 ; on May 17, 2022.

Keywords: Refractive outcomes; Rotational stability; Toric intraocular lens.

Fig. 1

Rotation of the toric intraocular lenses from the end of surgery to 6 months after surgery (orange) and between the individual follow-up visits (blue). EOS, end of surgery; h, hour; m, month

Fig. 2

Comparison of preoperative corneal astigmatism (a) and postoperative refractive astigmatism (b) at the corneal plane in a double-angle plot. A clear centralization of the vectors around the center can be seen postoperatively. The centroid of the postoperative refractive astigmatism is statistically different from zero

Fig. 3

Double-angle plot of the surgically induced astigmatism

Fig. 4

The standard graphs for reporting refractive outcomes for intraocular lens-based procedures in a cataract population. a Corrected and uncorrected visual acuity of all patients within ± 0.50 D spherical equivalent postoperatively. Figure 4a shows the cumulative corrected and uncorrected distance visual acuity for all eyes targeted for plano. b Uncorrected distance visual acuity versus corrected distance visual acuity. Figure 4b shows percentage of eyes having the same or worse uncorrected distance visual acuity in comparison to corrected distance visual acuity. c Spherical equivalent refraction accuracy. Figure 4c shows the spherical equivalent refraction accuracy for all eyes. A slightly hyperopic shift was observed. d Distribution of the postoperative refractive cylinder. Figure 4d shows the refractive cylinder achieved postoperatively. Ninety percent of eyes achieved a residual postoperative refractive cylinder within 0.50 D and 99% of eyes achieved a residual postoperative refractive cylinder within 1.00 D

Fig. 5

An image series of the rotational stability evaluation on a right eye with a total rotation of only 0.08° after 6 months postoperatively

Fig. 6

An image series of the rotational stability evaluation on a left eye with a rotation of 19.45° between 1 h and 1 week after the end of surgery