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

Author(s):  
Ken Hayashi ◽  
Motoaki Yoshida ◽  
Shunsuke Hayashi ◽  
Akira Hirata

Abstract Purpose To examine the long-term changes in the astigmatism-correcting effect of a toric intraocular lens (IOL) after stabilization of surgically induced astigmatic changes due to cataract surgery. Methods Unilateral eyes of 120 patients that received a toric IOL for against-the-rule (ATR) or with-the-rule (WTR) astigmatism were enrolled. Manifest refractive and anterior corneal astigmatism, and ocular residual astigmatism which is mainly derived from internal optics were examined preoperatively, at approximately 2 months postoperatively (baseline) and at 5 ~ 10 years postbaseline. The astigmatism was decomposed to vertical/horizontal (Rx) and oblique components (Ry), which was compared between baseline and 5 ~ 10 years postbaseline. Results In the eyes having ATR astigmatism, the mean Rx and Ry of the manifest refractive and corneal astigmatism significantly changed toward ATR astigmatism between the baseline and 5 ~ 10 years postbaseline (p ≤ 0.0304), but those of ocular residual astigmatism did not change significantly between the 2 time points. In the eyes having WTR astigmatism, the Rx and Ry of refractive, corneal, and ocular residual astigmatism did not change significantly between the 2 time points. Double-angle plots revealed an ATR shift in refractive and corneal astigmatism and no marked change in the ocular residual astigmatism in the eyes with ATR astigmatism, and there is no change in this astigmatism in the eyes with WTR astigmatism. Conclusion The long-term changes with age in the effect of a toric IOL significantly deteriorated due to an ATR shift of corneal astigmatism in the eyes having ATR astigmatism, while it was maintained in eyes having WTR astigmatism, suggesting that ATR astigmatism should be overcorrected.

2020 ◽  
Author(s):  
Da young Shin ◽  
Ho Sik Hwang ◽  
Hyun Seung Kim ◽  
Man Soo Kim ◽  
Eun Chul Kim

Abstract Background: To analyze and compare the clinical results of toric intraocular lens (IOL) and monofocal IOL implantation when the target refraction value is determined -3 diopter (D) in cataract patients with corneal astigmatism >1.5 diopters (D).Methods: We performed a retrospective chart review for patients with corneal astigmatism >1.5D who underwent cataract surgery and their target refraction is determined -3D. 100 eyes (100 patients; monofocal IOL, 60; toric IOL, 40) were enrolled in the current study. Near and distant uncorrected visual acuity (UCVA), corrected VA, spherical equivalent and refractive, corneal astigmatism were evaluated before and after surgery.Results: The near UCVA of the toric IOL group (0.26±0.33) after cataract surgery was significantly better than that of the monofocal IOL group (0.48±0.32) (p=0.030). The distant UCVA of the toric IOL group (0.38 ± 0.14) was also significantly better than that of the monofocal IOL group (0.55 ± 0.22) (p = 0.026). There were no significant intergroup differences in postoperative best-corrected visual acuity (p = 0.710) and mean spherical equivalent (p = 0.465). In the toric IOL group, postoperative refractive astigmatism was -0.80 ± 0.46D and postoperative corneal astigmatism was -1.50 ± 0.62D, whereas the corresponding values in the monofocal IOL group were -1.65 ± 0.77D and -1.45 ± 0.64D; residual refractive astigmatism was significantly lower with toric IOL implantation compared with monofocal IOL implantation (p = 0.001). Conclusions: When myopic refraction such as -3D was determined as the target power in patients with corneal astigmatism, toric IOL implantation led to excellent improvement in both near and distant UCVA.


2020 ◽  
Author(s):  
Hye Ji Kwon ◽  
Hun Lee ◽  
Jin Ah Lee ◽  
Jae Yong Kim ◽  
Hungwon Tchah

Abstract Objectives To compare the efficacy of astigmatic correction between simultaneous femtosecond laser-assisted intrastromal arcuate keratotomy (AK) combined with femtosecond laser-assisted cataract surgery (FLACS) and toric intraocular lens (IOL) implantation during cataract surgery in moderate astigmatism. Design: Retrospective observational study, tertiary care medical center Methods We retrospectively reviewed medical records of patients who underwent astigmatic correction via femtosecond laser-assisted intrastromal AK (AK group; 27 eyes of 27 patients) with FLACS or toric IOL implantation (toric IOL group; 21 eyes of 21 patients). All patients had senile cataracts with corneal astigmatism ranging from + 1.00 to + 2.00 diopters (D) before cataract surgery. We measured visual acuity, intraocular pressure, automated keratometry, manifest refraction and topography preoperatively and at 1-day, 1-month, 3-month, and 6-month postoperatively. Results Refractive astigmatism was significantly decreased in both groups. The mean preoperative and 6-month postoperative refractive astigmatism were 1.85 ± 1.07 and 0.99 ± 0.51 D, respectively, in the AK group (P = 0.028), and 1.84 ± 0.81 and 0.68 ± 0.21 D, respectively, in the toric IOL group (P < 0.001). There was no significant difference in refractive astigmatism between the two groups at 6-month postoperatively (0.99 ± 0.51 vs 0.68 ± 0.21 D, P = 0.057). At 6-month postoperatively, parameters for vector analysis of refractive astigmatism showed no statistical difference between the two groups. Corneal astigmatism was significantly decreased in the AK group. There was significant difference in corneal astigmatism from topography and automated keratometer between the two groups at 6-month postoperatively (0.94 ± 0.40 vs 1.53 ± 0.46 D, P = 0.018 for topography and 0.98 ± 0.69 vs 1.37 ± 0.41 D, P = 0.032 for automated keratometer). Conclusions Femtosecond laser-assisted intrastromal AK in FLACS could be an effective procedure for reducing astigmatism as well as toric IOL implantation in cataract surgery.


2020 ◽  
Author(s):  
Da young Shin ◽  
Ho Sik Hwang ◽  
Hyun Seung Kim ◽  
Man Soo Kim ◽  
Eun Chul Kim

Abstract Background: The aim of this study is to analyze and compare the clinical results of toric intraocular lens (IOL) and monofocal IOL implantation when the target refraction value is determined -3 diopter (D) in cataract patients with corneal astigmatism >1.5 diopters (D).Methods: We performed a retrospective chart review for patients with corneal astigmatism >1.5D who underwent cataract surgery and their target refraction is determined -3D. 100 eyes (100 patients; monofocal IOL, 60; toric IOL, 40) were enrolled in the current study. Near and distant uncorrected visual acuity (UCVA), corrected VA, spherical equivalent and refractive, corneal astigmatism were evaluated before and after surgery.Results: The near UCVA of the toric IOL group (0.26±0.33) after cataract surgery was significantly better than that of the monofocal IOL group (0.48±0.32) (p=0.030). The distant UCVA of the toric IOL group (0.38 ± 0.14) was also significantly better than that of the monofocal IOL group (0.55 ± 0.22) (p = 0.026). There were no significant intergroup differences in postoperative best-corrected visual acuity (p = 0.710) and mean spherical equivalent (p = 0.465). In the toric IOL group, postoperative refractive astigmatism was -0.80 ± 0.46D and postoperative corneal astigmatism was -1.50 ± 0.62D, whereas the corresponding values in the monofocal IOL group were -1.65 ± 0.77D and -1.45 ± 0.64D; residual refractive astigmatism was significantly lower with toric IOL implantation compared with monofocal IOL implantation (p = 0.001). There were no postoperative complications and no adverse events were reported.Conclusions: When myopic refraction such as -3D was determined as the target power in patients with corneal astigmatism, toric IOL implantation led to excellent improvement in both near and distant UCVA.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hoon Noh ◽  
Young-Sik Yoo ◽  
Kyoung Yoon Shin ◽  
Dong Hui Lim ◽  
Tae-Young Chung

AbstractThis study tried to compare the clinical outcomes of femtosecond laser-assisted astigmatic keratotomy (FSAK) and toric intraocular lens (IOL) implantation for astigmatism correction and identify factors affecting the efficacy of FSAK and toric IOL implantation in astigmatism correction. This retrospective case series comprised patients with corneal astigmatism ranging between 0.5 D and 4.5 D. Patients underwent FSAK or toric IOL implantation for cataract treatment and correction of astigmatism at the Samsung Medical Center, a tertiary surgical center, between April 2016 and December 2018. All patients underwent examination before and at three months after the surgery for comparative evaluation of refractive astigmatism, corneal high order aberrations and irregularity index. The astigmatism correction was analyzed by the Alpins method. Subgroup analysis of preoperative factors was based on the extent of target-induced astigmatism (TIA), the degree of astigmatism, and astigmatism classification based on topography. Thirty-one eyes underwent toric IOL implantation and 35 eyes underwent FSAK. The refractive astigmatism was significantly decreased in both toric IOL (P = 0.000) and FSAK group (P = 0.003). The correction index (CI) of refractive astigmatism was 0.84 ± 0.39 in the toric IOL and 0.71 ± 0.60 in the FSAK group. There was no difference between the two groups (P = 0.337). The CI of the FSAK group was significantly lower than in the toric IOL group when TIA was more than 1.5 D (P = 0.006), when correcting against-the-rule (P = 0.017), and limbus-to-limbus astigmatism (P = 0.008). In conclusion, toric IOL implantation is an effective and safe procedure for correcting preoperative astigmatism in cataract surgery in the short-term observation.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hye Ji Kwon ◽  
Hun Lee ◽  
Jin Ah. Lee ◽  
Jae Yong Kim ◽  
Hungwon Tchah

Abstract Background To compare the efficacies in astigmatic correction of simultaneous femtosecond laser-assisted cataract surgery (FLACS) with intrastromal arcuate keratotomy (ISAK) versus toric intraocular lens (IOL) implantation with conventional phacoemulsification in moderate astigmatism. Methods A retrospective chart review was conducted for patients who had undergone cataract surgery by one surgeon. We identified patients with preoperative corneal astigmatism from + 0.75 to + 2.00 diopters (D) who had undergone astigmatic correction with FLACS with ISAK or toric IOL implantation with conventional phacoemulsification. We measured the visual acuity, intraocular pressure, automated keratometer, manifest refraction, and topography preoperatively and 1-day, 1-month, 3-month, and 6-month postoperatively. The vector analysis of refractive astigmatism was performed. Results Of a total of 48 eyes of 48 patients, 27 eyes of 27 patients had FLACS with ISAK (AK group), and 21 eyes of 21 patients had conventional cataract surgery with toric IOL implantation (toric IOL group). Refractive astigmatism was significantly decreased in both groups. The mean preoperative and 6-month postoperative refractive astigmatism were 1.85 ± 1.07 and 0.99 ± 0.51 D, respectively, in the AK group (P = 0.028), and 1.84 ± 0.81 and 0.68 ± 0.21 D, respectively, in the toric IOL group (P < 0.001). There was no significant difference in refractive astigmatism between the two groups at 6-month postoperatively (0.99 ± 0.51 vs 0.68 ± 0.21 D, P = 0.057). At 6-month postoperatively, parameters for vector analysis of refractive astigmatism showed no statistical difference between the two groups. Corneal astigmatism was significantly decreased in the AK group. Corneal astigmatism from topography and the automated keratometer were significantly lower in the AK group 6-month postoperatively compared to toric IOL group (0.94 ± 0.40 vs. 1.53 ± 0.46 D, P = 0.018 for topography; and 0.98 ± 0.69 vs. 1.37 ± 0.41 D, P = 0.032 for the automated keratometer). Conclusions FLACS with ISAK could be an effective procedure for reducing astigmatism as well as toric IOL implantation in cataract surgery.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Zhe Zhang ◽  
Hui Li ◽  
Jing Zhou ◽  
Yaqin Zhang ◽  
Suhua Zhang

Abstract Background Currently, there is no standard technique for determining corneal astigmatism. The iTrace wavefront aberrometry of cornea calculated steep power and axis based on the best Zernike mathematical fit from all topo data within 4 mm circle. It was supposed to be more accurate than iTrace simulated keratometry which was calculated based on only 4 points on the circle of 3 mm. This aim of this study was to evaluate visual outcomes and rotational stability after toric intraocular lens (IOL) implantation using the wavefront aberrometry of the cornea with iTrace. Setting: Single site in China, Shanxi Eye Hospital, Shanxi, China. Design: Prospective case series. Methods The study included 85 eyes of 63 patients undergoing phacoemulsification and toric IOL implantation. The IOL power and cylinders were chosen with the help of the iTrace toric planning program using wavefront keratometric astigmatism. Astigmatic changes were assessed using Alpins vector method over a 3-month follow-up period. Results Preoperative mean corneal topographic astigmatism was 1.91 diopters (D) ± 0.69 (standard deviation). Postoperative mean refractive astigmatism decreased significantly to 0.48 D ± 0.34. Surgical induced astigmatism was 1.73 D ± 0.77 and the mean correction index was 0.89 ± 0.22, showing a slight undercorrection. The proportion of astigmatism ≤0.50 D increased from 0 to 71.8% postoperatively. Conclusions This is the first study on evaluation of clinical outcomes of toric IOL implantation in corneal astigmatism patients using iTrace wavefront keratometric readings. The findings show that use of iTrace built-in toric calculator is safe and effective for planning toric IOL surgery for wavefront keratometric astigmatism. Trial registration Current Controlled Trials ISRCTN94956424, Retrospectively registered (Date of registration: 05 February 2020).


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Atsushi Kawahara

Abstract Background To determine the preoperative factors influencing refractive astigmatism after cataract surgery for astigmatism correction by toric intraocular lens (IOL) implantation and to evaluate the prediction model using these factors. Methods Prospective, observational case series. The right eyes of forty consecutive patients with preoperative corneal astigmatism of the total cornea of 1.5 diopters (D) or more in magnitude and scheduled for implantation of a non-toric IOL during cataract surgery with a 2.4-mm temporal clear corneal incision were examined prospectively. The vertical/horizontal astigmatism component (J0) and oblique astigmatism component (J45) of refractive and corneal astigmatism were converted using power vector analysis. Multivariate regression analysis was performed with refractive astigmatism at three months postoperatively as the dependent variable, and preoperative parameters including age, sex, refractive astigmatism, corneal astigmatism, sphere, spherical equivalent, intraocular pressure, corneal thickness, anterior chamber depth, lens thickness, lens positions (tilt and decentration), axial length, and corneal higher order aberrations as independent variables. The root mean square (RMS) errors were calculated to express the regression model fit. Results The regression model for the J0 component was $$ Postoperative\kern0.34em refractive\kern0.2em J0=1.05\times Coneal\kern0.2em J0-0.14 $$ P o s t o p e r a t i v e r e f r a c t i v e J 0 = 1.05 × C o n e a l J 0 − 0.14 (R2 = 0.96, P < 0.001). The model for the J45 component was $$ Postoperative\kern0.34em refractive\kern0.2em J45=0.68\times Coneal\kern0.2em J45+0.19\times Preoperative\kern0.34em refractive\kern0.2em J45-0.06 $$ P o s t o p e r a t i v e r e f r a c t i v e J 45 = 0.68 × C o n e a l J 45 + 0.19 × P r e o p e r a t i v e r e f r a c t i v e J 45 − 0.06 (R2 = 0.72, P < 0.001). The mean RMS errors for preoperative corneal astigmatism alone and the multivariate model were 0.58 D and 0.46 D, respectively. There was a statistically significant difference between them (P = 0.02). Conclusions Refractive astigmatism after implantation of a toric IOL can be predicted by the regression model more accurately than by corneal astigmatism alone. However, the prediction of oblique astigmatism remains a challenge.


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