Long-term changes in the refractive effect of a toric intraocular lens on astigmatism correction

Medium-term visual and refractive outcomes in patients with pseudoexfoliation implanted with a toric or multifocal intraocular lens

PURPOSE

To report medium-term visual acuity and refractive outcomes of patients with pseudoexfoliation implanted with toric or multifocal intraocular lenses (IOLs).

METHODS

We retrospectively reviewed patients with pseudoexfoliation who had undergone phacoemulsification between 2016 and 2020 with at least 24 months follow-up.

RESULTS

Mean follow-up was 44.17 ± 14.95 months. Toric IOLs were implanted in 48 eyes: mean uncorrected LogMAR visual acuity one month after surgery was 0.03 ± 0.09, decreasing to 0.08 ± 0.11 at the last visit (p = .01). Mean refractive cylinder was -0.12 ± 0.36 diopters one month after surgery and -0.25 ± 0.44 diopters at the last follow-up visit, p = .012. Multifocal IOLs were implanted in 42 patients: binocular uncorrected distance visual acuity was -0.02 ± 0.04 one month after surgery and 0.01 ± 0.05 at the last visit (p = .004); near acuity was 0.01 ± 0.03 and 0.04 ± 0.06 respectively (p = .001). In eyes with pseudoexfoliation, absolute spherical equivalent prediction error was 0.22 ± 0.20 diopters for toric and 0.21 ± 0.19 diopters for multifocal IOLs. One month after surgery 68.6% of eyes with toric IOLs and 74.2% of eyes with multifocal IOLs were within ±0.25 diopters of target spherical equivalent and 91.6% and 90.5% were within ±0.5 diopters, respectively. Spherical equivalent did not change significantly during follow-up for either group.

CONCLUSION

Prediction error in eyes with pseudoexfoliation implanted with toric or multifocal IOLs was low and similar to values reported for normal eyes. Postoperative refractive cylinder with toric IOLs was low, with little change during follow-up. Visual function in patients receiving multifocal IOLs was excellent. Therefore, the implantation of these IOLs in eyes with pseudoexfoliation does not seem to cause medium-term problems.

Clinical Outcomes of Toric Intraocular Lenses in Patients with Fuchs Endothelial Corneal Dystrophy

INTRODUCTION

Implantation of toric intraocular lenses (IOLs) in patients with Fuchs endothelial corneal dystrophy (FECD) is still considered relatively contraindicated, without sufficient clinical evidence. Therefore, this study was designed to evaluate the results of toric IOL implantation in patients with FECD.

METHODS

A retrospective case-control study of 28 eyes of FECD patients and 84 eyes of healthy control patients who received toric IOLs during routine cataract surgery was performed. The outcome measures were uncorrected and corrected distance visual acuity, spherical equivalent, and refractive residual astigmatism.

RESULTS

The mean postoperative uncorrected and corrected distance visual acuity in the FECD eyes compared to the control eyes were 0.15 ± 0.14 vs. 0.13 ± 0.17, respectively (P = 0.32), and 0.05 ± 0.08 vs. 0.06 ± 0.10, respectively (P = 0.95). The spherical equivalent in the FECD eyes compared to the control eyes was - 0.29 ± 0.43 vs. - 0.21 ± 0.50, respectively (P = 0.19). The preoperative corneal centroid astigmatism in the FECD eyes compared to the control eyes was 0.85 D@93° ± 2.42° vs. 0.23 D@68° ± 2.50°, respectively (P = 0.43), and the mean preoperative corneal astigmatism magnitude was 2.26 ± 1.1 D vs. 2.28 ± 1.03 D, respectively (P = 0.82). A trend toward higher postoperative refractive centroid astigmatism was found in the FECD eyes compared with the control eyes: 0.24 D@28° ± 0.57° vs. 0.03 D@127° ± 0.53°, respectively (P = 0.09). However, the mean refractive astigmatism magnitude was similar in FECD eyes and the healthy control eyes: 0.52 ± 0.31 D vs. 0.42 ± 0.31 D, respectively (P = 0.44) (D diopters).

CONCLUSION

The postoperative refractive astigmatism (both centroid astigmatism and mean magnitude astigmatism) was no higher than 0.52 D in both groups. Therefore, FECD patients without corneal edema can be considered for toric IOLs.

Predicting Residual Astigmatism in Cataract Surgery

The purpose of this review is to evaluate the prediction of postoperative residual astigmatism and to determine the best prediction method for astigmatism correction. In recent findings for residual astigmatism in non-toric monofocal intraocular lens (IOL) implanted eyes, vector analysis can be used to correctly evaluate residual astigmatism by decomposing it. In predicting residual astigmatism, the with-the-rule (WTR) and against-the-rule (ATR) astigmatism components can now be almost predicted. This may be due to advances in inspection equipment and surgical technique. However, there are still issues with the oblique astigmatism component. In addition, corneal astigmatism is the most important predictor of postoperative residual astigmatism, and other predictors, such as refractive astigmatism, age, and lens thickness, have also been mentioned. However, all but corneal astigmatism are questionable because of the possibility of confounding variables. Total corneal astigmatism is more accurate in predicting residual astigmatism than anterior corneal astigmatism. Several predictions of residual astigmatism have been reported, but complete prediction has not been possible. Further research is needed, especially in predicting oblique astigmatism. However, I emphasize that the accuracy of predicting WTR and ATR astigmatism has improved considerably and can be predicted using regression equations with total corneal astigmatism.

Propensity-matched comparison of postoperative stability and visual outcomes of toric intraocular lens with or without a capsular tension ring and updated meta-analysis

PURPOSE

To assess the contribution of capsular tension ring (CTR) to postoperative stability and visual outcomes of a plate-haptic toric intraocular lens (IOL).

METHODS

This prospective cohort study was performed among patients underwent toric IOL (AT TORBI 709 M) implantation with or without CTR at the Eye and ENT hospital between April 2020 and November 2021. Propensity score matching (PSM) was performed to balance baseline factors. Postoperatively, uncorrected distance visual acuity (UCVA) and residual astigmatism, as well as IOLs' rotation, tilt, and decentration, were analyzed. Grouped multiple linear regression analysis was used to model predictive factors of rotation in each group. Additionally, a meta-analysis of data from 4 publications (284 eyes) and current study was performed to evaluate the effect of CTR co-implantation on toric IOL rotation.

RESULTS

After PSM, 126 eyes from each group were included for further analysis. Postoperatively, UDVA was 0.31 ± 0.38 logMAR and 0.27 ± 0.36 logMAR in the CTR and NCTR groups, respectively (P = 0.441), and residual astigmatism was 0.75 ± 0.52 D and 0.86 ± 0.65 D, respectively (P = 0.139). The rotation of toric IOL was significantly smaller in the CTR group than in the NCTR group (4.63 ± 6.27 vs. 10.93 ± 16.05 degrees, P < 0.001). The regression models of the two groups and the coefficients of LT were significantly different (P < 0.001 and P = 0.001, respectively). Furthermore, the meta-analysis confirmed that CTR co-implantation reduced toric IOL rotation (MD, - 1.59; 95% CI, - 3.10 to - 0.09; P = 0.038).

CONCLUSION

CTR enhances rotational stability of toric IOL by reducing the impact of LT, and CTR co-implantation is recommended in patients with lens thickness (LT) ≥ 4.5 mm, white-to-white (WTW) ≥ 11.6 mm, or high preexisting astigmatism.

Long-term outcomes of cataract surgery with toric intraocular lens implantation by the type of preoperative astigmatism

Surgical outcomes of toric intraocular lens (IOL) implantation for 8 years after surgery were analyzed. Data were retrospectively collected in 176 eyes of 176 patients before and 1 month, 1, 3, 5, and 8 years after phacoemulsification and implantation of a toric IOL. Preoperative corneal and postoperative manifest astigmatism was analyzed by converting to power vector notations; horizontal/vertical (J₀) and oblique (J₄₅) astigmatism components. Toric IOL implantation significantly reduced pre-existing astigmatism by decreasing J₀ in eyes with preoperative with-the-rule (WTR) astigmatism, increasing J₀ in eyes with against-the-rule (ATR) astigmatism, and correcting J₄₅ in eyes with oblique astigmatism. After surgery, the eyes with preoperative ATR astigmatism showed a significant ATR astigmatic shift, and J₀ at 5 and 8 years was significantly smaller than that at 1 month postoperatively. Uncorrected distance visual acuity was also significantly worse at 5 and 8 years than at 1 month postoperatively. In eyes with WTR and oblique astigmatism, the effects of toric IOLs on astigmatism and visual acuity were sustained for 8 years. The long-term astigmatism-correcting effects did not differ among the models of toric IOL used in this study, SN6AT3–8 (Alcon Laboratories). In eyes with preoperative ATR astigmatism, astigmatism-correcting effects of toric IOLs decreased at 5 years and later postoperatively, indicating that overcorrection may be considered at the time of cataract surgery. In eyes with WTR and oblique astigmatism, the effects of toric IOLs were maintained throughout the 8-year follow-up period.

Comparison of long-term astigmatic changes following cataract surgery among types of corneal astigmatism

AIMS

To examine whether long-term corneal astigmatic changes after stabilisation of surgically induced astigmatism (SIA) following cataract surgery differ among eyes having against-the-rule (ATR), with-the-rule (WTR), and oblique astigmatism.

METHODS

Anterior corneal astigmatism of 390 eyes in 390 patients (130 eyes each having ATR, WTR and oblique astigmatism) who underwent phacoemulsification with a horizontal clear corneal or scleral incision and 390 eyes in 390 control patients without surgery were examined using an auto-keratometer on the day that SIA stabilised (baseline) and at ≥8 years post baseline. Changes in corneal astigmatism during the ≥8 years post baseline were decomposed to vertical/horizontal (Rx) and oblique astigmatism components (Ry), and compared among baseline types of astigmatism and between eyes with and without surgery.

RESULTS

The mean corneal astigmatic changes (Rx and Ry) showed an ATR shift of 0.2-0.3 D during the ≥8 years post baseline, which did not differ significantly among the ATR, WTR and oblique astigmatism groups in eyes with and without surgery. In the ATR, WTR and oblique groups, the mean Rx and Ry did not differ significantly between eyes with and without surgery. Double angle plots revealed an equivalent degree of ATR change in the ATR, WTR and oblique groups between eyes with and without surgery.

CONCLUSION

Long-term corneal astigmatic changes towards ATR astigmatism occurred to a similar extent in eyes having ATR, WTR, oblique astigmatism and were comparable between eyes with and without surgery, suggesting that astigmatism type need not be considered when planning astigmatism correction.