Effect of capsular tension ring implantation on capsular stability after phacoemulsification in patients with weak zonules: a randomized controlled trial. CTR implantation in cataract patients with weak zonules

Effectiveness of prophylactic capsular tension ring implantation during cataract surgery in highly myopic eyes

PURPOSE

To assess the effectiveness of prophylactic capsular tension ring (CTR) implantation during cataract surgery in highly myopic eyes.

SETTING

Eye and Ear, Nose, and Throat Hospital of Fudan University, Shanghai, China.

DESIGN

Prospective cohort study.

METHODS

Consecutive highly myopic patients treated with cataract surgery were recruited and randomized to undergo CTR implantation or not. The outcomes compared between the 2 groups included axial lens position (ALP), intraocular lens (IOL) decentration and tilt, area of anterior capsule opening, severity of anterior capsular opacification (ACO), and posterior capsular opacification (PCO) at 1 year postoperatively.

RESULTS

A total of 55 highly myopic eyes with CTRs implanted and 55 without were included in the analysis. At 1 year postoperatively, no significant differences were detected between the CTR and non-CTR groups for the mean ALP, IOL decentration, or tilt (all P > .05). However, the CTR group had a significantly larger area of anterior capsule opening (23.62 ± 3.30 mm2 vs 21.85 ± 2.30 mm2, P = .003), and less severe ACO (P = .033) and PCO (PCO-3 mm: 0.06 ± 0.13 vs 0.13 ± 0.20, P = .038; PCO-C: 0.15 ± 0.18 vs 0.25 ± 0.26, P = .026) than the non-CTR group. The corrected distance visual acuity, prediction error, and higher-order aberrations did not differ between the 2 groups (all P > .05).

CONCLUSIONS

In highly myopic eyes, although prophylactic CTR implantation can reduce the severity of capsular contraction and opacification, it does not significantly affect postoperative IOL stability or visual outcomes.

Influence of Capsular Tension Rings on the IOL-Capsule Complex in Patients With Long Axial Length: A Clinical Observation Based on SS-OCT

PURPOSE

To evaluate the influence of a capsular tension ring (CTR) on the intraocular lens (IOL)-capsule complex after cataract surgery in patients with long axial length.

METHODS

This was a prospective study. Patients underwent phacoemulsification and IOL implantation, with or without CTR implantation. Swept-source optical coherence tomography was performed at 1 day, 1 week, 1 month, and 3 months postoperatively to determine the postoperative aqueous depth (PAD), capsular bend index (CBI), and IOL tilt and decentration. Spherical equivalent values were obtained through subjective refraction and autorefraction. Root mean square was adopted to evaluate the indices listed above.

RESULTS

Forty-three patients (56 eyes) were included in the study. Generalized estimating equation analysis of PAD showed a statistical difference between groups (P = .031). The RMS of the change in PAD was smaller in the CTR group than in the non-CTR group during the 3 months after surgery (P = .015). CBI in the CTR group increased more from 1 to 3 months after surgery than that in the non-CTR group (P = .025). The RMS of the change in vertical decentration was smaller in the CTR group than in the non-CTR group during the 3-month follow-up (P = .009).

CONCLUSIONS

CTR implantation can stabilize the axial position of the IOL within the capsular bag after cataract surgery in patients with long axial length without affecting the refractive stability. The formation of capsular bend may be slightly delayed in the early stage after CTR implantation, but it accelerates from 1 to 3 months after surgery. [J Refract Surg. 2024;40(9):e654-e661.].

Capsular Tension Ring Implantation for Intraocular Lens Decentration and Tilt in Highly Myopic Eyes: A Randomized Clinical Trial

Importance

Capsular tension rings (CTRs) can support weak zonules and inhibit capsular shrinkage, thus potentially reducing intraocular lens (IOL) decentration and tilt. However, it has been debated whether CTRs can reduce IOL decentration and tilt in highly myopic eyes and whether CTR implantation is necessary for all highly myopic eyes.

Objective

To evaluate the influence of CTR implantation on IOL decentration and tilt in highly myopic eyes.

Design, Setting, and Participants

This randomized clinical trial was conducted between November 2021 and September 2023 at the Zhongshan Ophthalmic Center, Guangzhou, China. Patients with cataract and an axial length (AL) of 26 mm or longer were enrolled.

Interventions

Participants were stratified into 3 groups based on the AL (stratum 1, 26 mm ≤ AL <28 mm; stratum 2, 28 mm ≤ AL <30mm; stratum 3, AL ≥30 mm), and further randomly assigned to the CTR group (a C-loop IOL combined with a CTR) or the control group (only a C-loop IOL) within each stratum.

Main Outcomes and Measures

IOL decentration at 3 months after cataract surgery was evaluated using anterior segment optical coherence tomography.

Results

A total of 186 eyes of 186 participants (mean [SD] age, 57.3 [10.9] years; 118 female [63.4%]) were randomized into the CTR group (93 [50%]) or control group (93 [50%]), with 87 eyes (93.6%) and 92 eyes (98.9%) completing follow-up at 3 months, respectively. The CTR group showed smaller IOL decentration (0.19 mm vs 0.23 mm; difference, -0.04 mm; 95% CI, -0.07 to -0.01 mm; P = .02) and tilt at 3 months, and lower proportions of clinically significant IOL decentration (≥0.4 mm) and tilt (≥7°) at 3 months compared with the control group. Similar results were only found in eyes with an AL of 30 mm or longer (IOL decentration: 0.20 mm vs 0.28 mm; difference, -0.08 mm; 95% CI, -0.14 to -0.02 mm; P = .01). Additionally, the CTR group showed a smaller change in IOL decentration from 1 week to 3 months, higher prediction accuracy, and better visual quality and patient satisfaction in this stratum. No differences were observed between the CTR and control groups in eyes with an AL less than 30 mm.

Conclusions and Relevance

CTR implantation reduced C-loop IOL decentration and tilt, increased position stability, and improved visual quality in eyes with an AL of 30 mm or longer. These findings support use of CTR implantation in eyes with an AL of 30 mm or longer and implanted with C-loop IOLs.

Trial Registration

ClinicalTrials.gov Identifier: NCT05161520.

Distribution and associations of anterior lens zonules lengths in patients with cataract

PURPOSE

To investigate the characteristics and associations of anterior lens zonules lengths in cataract patients via ultrasound biomicroscope (UBM) measurement.

METHODS

Patients with age-related cataracts and high myopic cataracts who planned to undergo cataract surgery were included in the study. After routine ophthalmic examinations, the UBM was performed on both eyes to get images of the anterior lens zonules, and Image J software was used to measure the lengths of the lens zonules. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) diameter of both eyes were obtained by IOL Master 700. Univariate and multivariate regression analyses were used to assess associated factors of anterior lens zonules lengths.

RESULTS

Forty-nine patients with age-related cataracts and 33 patients with high myopic cataracts were enrolled. High myopic cataract patients were younger and had longer anterior lens zonules. Multivariate regression analysis showed that anterior lens zonules lengths were associated with axial lengths (temporal location: β = 0.036, P = 0.029; nasal location: β = 0.034, P = 0.011; superior location: β = 0.046, P = 0.002) and ACD (inferior location: β = 0.305, P = 0.016) in right eyes. In left eyes, anterior lens zonules lengths were associated with axial lengths (temporal location: β = 0.028, P = 0.017; inferior location: β = 0.026, P = 0.016; nasal location: β = 0.033, P < 0.001) and ACD (inferior location: β = 0.215, P = 0.030; superior location: β = 0.290, P = 0.011).

CONCLUSIONS

High myopic cataract patients have longer anterior lens zonules. AL and ACD contributed to the lengths of anterior lens zonules. Thus, for patients with long AL and deeper ACD, lens zonules measurement was crucial.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn identifier is ChiCTR2300071397.

Effect of Implanted Capsular Tension Ring on Postoperative Refractive Shift: A Systematic Review and Meta-Analysis

BACKGROUND

The capsular tension ring is a novel assistant tool for cataract surgery; however, controversy exists in its co-implantation. The potential for hyperopic or myopic shift resulting from the co-implantation of the capsular tension ring and intraocular lens remains unclear. This study aimed to determine the postoperative refractive prediction error and the direction of refractive shift in cataract patients who underwent capsular tension ring co-implantation.

METHODS

We conducted a systematic review and meta-analysis,searching electronic databases for studies of individuals diagnosed with cataracts receiving surgery with or without capsular tension ring implantation. Systematic searches were performed based on five databases: PubMed, Cochrane Library, Web of Science, Medline, and China National Knowledge Infrastructure. The primary outcome was the mean arithmetic refractive prediction error. Secondary outcomes were mean absolute refractive prediction error and the number of eyes within a certain refractive prediction error range. We applied a fixed-effectsmodel to pool effect sizes across trials using weighted mean differences (WMD) and risk ratios (RR) with their 95% confidence intervals (95% CI). Statistical heterogeneity scores were assessed with the I2statistic.

RESULTS

A total of 407 affected eyes were included in eight independent clinical studies. Meta-analysis suggested significant differences both in short-term (≤1 month) co-implantation (WMD = 0.16, p < .001, 95% CI: -0.13 ~ 0.19) and long-term (≥3 months) co-implantation between the capsular tension ring co-implantation group and the control group (WMD = 0.19, p < .001, 95% CI: 0.15 ~ 0.23). However, no significant difference was observed in the high myopia subgroup whether capsular tension ring co-implantation (WMD = 0.03, p = .083, 95% CI: -0.27 ~ 0.34). Heterogeneity was not found among the studies.

CONCLUSION

Compared to simple intraocular lens implantation, capsular tension ring co-implantation is more susceptible to developing hyperopic shifts in non-myopic cataract patients, probably related to anterior chamber depth. It requires careful consideration by clinicians when determining the target diopter preoperatively. However, interpretation is limited, because there is a lack of studies available for analysis. There still needs to be additional studies to expand the evidence base.

Effect of capsule treatment on visual acuity and quality after phacoemulsification lens implantation in myopic patients with cataract

BACKGROUND

Cataracts pose a significant clinical burden due to their complex pathogenesis. In recent years, an increase in cataracts coexisting with myopia has heightened the incidence of retinopathy and posterior vitreous detachment. Additionally, symptoms of ocular axis elongation, lens nucleus hardening, and vitreous liquefaction have become more prevalent. While conventional extracapsular cataract extraction is commonly employed, it often yields suboptimal visual outcomes. Subsequent advancements in cataract phacoemulsification and lens implantation surgeries have gained widespread acceptance for their ability to improve refraction and significantly improve uncorrected visual acuity.

AIM

To investigate the effect of capsular treatment after phacoemulsification lens implantation in myopic patients with cataract.

METHODS

We selected 110 patients (with 134 eyes) with myopia and cataracts treated. These patients were categorized into two groups: an observation group (57 patients with 70 eyes) and a control group (53 patients with 64 eyes). The control group underwent cataract phacoemulsification and lens implantation, while the observation group received a refined capsular treatment based on the control group's procedure. We assessed the differences in visual acuity and quality between the two groups before and after surgery.

RESULTS

At six months post-operation, the observation group exhibited significantly improved far vision, intermediate vision, near vision, lower objective scattering index, higher Modulation transfer function cut-off frequency, and overall vision metrics at different contrast levels (100%, 20% and 9%) compared to the control group (P < 0.05). The total score of the National Eye Institute Visual Function Questionnaire in the observation group at 6 months after operation was significantly higher than that in the control group (P < 0.05). No significant difference in the incidence of adverse reactions was observed between the observation group and control group (P > 0.05).

CONCLUSION

Capsular treatment demonstrates efficacy in improving visual acuity and quality after phacoemulsification lens implantation in myopic patients with cataracts, warranting its clinical application.

Effect of capsular tension ring on the refractive outcomes of patients with extreme high axial myopia after phacoemulsification

PURPOSE

The aim of the study is to evaluate the effect of capsular tension ring (CTR) implantation following cataract surgery on the refractive outcomes of patients with extreme high axial myopia.

METHODS

Sixty eyes (with an axial length of ≥26 mm) were retrospectively reviewed and classified into two groups: CTR group (n = 30), which underwent CTR implantation following phacoemulsification, and control group (n = 30), which did not undergo CTR implantation. Intraocular lens (IOL) calculation was performed using Barrett Universal II (UII), Haigis, and SRK/T formulas. The refractive prediction error (PE) was calculated by subtracting the postoperative refraction from predicted refraction. The mean PE (MPE), mean absolute error (MAE), and percentages of eyes that had a PE of ±0.25, ±0.50, ±1.00, or ±2.00 diopters (D) were calculated and compared.

RESULTS

No significant differences were observed in PE between the two groups. The Barrett UII formula revealed a lower AE in the CTR group than in the control group (p = 0.015) and a lower AE than the other two formulas (p = 0.0000) in both groups. The Barrett UII formula achieved the highest percentage of eyes with a PE of ±0.25 D (66.67%).

CONCLUSIONS

The refractive outcomes were more accurate in eyes with CTR implantation than in those with routine phacoemulsification based on the Barrett UII formula. The Barrett UII formula was recommended as the appropriate formula when planning CTR implantation in high myopia.

Exploring anterion capsular contraction syndrome in cataract surgery: insights into pathogenesis, clinical course, influencing factors, and intervention approaches

Anterior capsular contraction syndrome (ACCS) is a challenging complication that can occur following phacoemulsification cataract surgery. Characterized by capsular bag wrinkling, intraocular lens (IOL) decentration and tilt, ACCS can have negative effects on visual outcomes and patient satisfaction. This review aims to investigate the pathogenesis, clinical course, influencing factors, and intervention approaches for ACCS after cataract surgery. By understanding the underlying mechanisms and identifying factors that contribute to ACCS, surgeons can enhance their ability to predict and manage this complication. Various intervention strategies are discussed, highlighting their importance in reducing complications and improving surgical outcomes. However, further research is needed to determine optimal prevention and management strategies through long-term follow-up and comparative analyses. Advancements in this field will ultimately lead to improved visual outcomes and optimized cataract surgery for patients.

Implantation of a capsular tension ring during cataract surgery attenuates predicted remodeling of the post-surgical lens capsule along the visual axis

Introduction: Cataract surgery permanently alters the mechanical environment of the lens capsule by placing a hole in the anterior portion and implanting an intraocular lens (IOL) that has a very different geometry from the native lens. We hypothesized that implant configuration and mechanical interactions with the post-surgical lens capsule play a key role in determining long-term fibrotic remodeling. Methods: We developed the first finite element-growth and remodeling (FE-G&R) model of the post-surgical lens capsule to evaluate how implantation of an IOL with and without a capsular tension ring (CTR) impacted evolving lens capsule mechanics and associated fibrosis over time after cataract surgery. Results: Our models predicted that implantation of a CTR with the IOL into the post-surgical lens capsule reduced the mechanical perturbation, thickening, and stiffening along the visual axis in both the remnant anterior and posterior portions compared to implantation of the IOL alone. Discussion: These findings align with patient studies and suggest that implantation of a CTR with the IOL during routine cataract surgery would attenuate the incidence of visually-debilitating capsule fibrosis. Our work demonstrates that use of such modeling techniques has substantial potential to aid in the design of better surgical strategies and implants.

Repeatability and reproducibility of anterior lens zonule length measurement using ArcScan Insight 100 very high-frequency ultrasound

OBJECTIVES

This study aimed to evaluate the intra-examiner repeatability and inter-examiner reproducibility in lens zonular length measurements using very high-frequency digital ultrasound (Insight 100).

METHODS

Two examiners performed ultrasound imaging independently in each subject. The length of temporal and nasal zonules were then measured with a built-in software. Coefficient of variations (CVs) of the three repeated measurements were used to determine intra-examiner variances. Inter-examiner reproducibility was evaluated using intraclass correlation coefficients (ICCs) and the Bland-Altman method.

RESULTS

40 eyes of 40 subjects (14male and 26female; mean age 23.9 ± 2.4 years) were included in the study. The CVs for intra-examiner measurement were 2.74% temporally and 4.32% nasally for Examiner 1, and were 1.96% temporally and 1.75% nasally for Examiner 2. For inter-examiner reproducibility, all ICCs were above 0.9. However, there were significant differences between the two examiners in temporal zonular length measurements (p = 0.001), and the differences mainly came from measuring the zonular length manually (p = 0.001) rather than recording images (p = 0.480). No significant differences were found between two measurements by the same examiner after one month (all p > 0.05, all ICCs＞0.8).

CONCLUSION

The Insight 100 device can be used to measure the length of anterior lens zonule with relatively good repeatability and reproducibility.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT05657951.

Differences Between Angle Configurations in Different Body Positions by Ultrasound Biomicroscopy in Patients with Cortical Age-Related Cataract

Purpose

To investigate the differences in parameters related to angle configuration and lens position in patients with cortical age-related cataract by ultrasound biomicroscopy (UBM) in different body positions.

Methods

Prospective study with 55 patients with cortical age-related cataract proposed for phacoemulsification, examined using a Compact Touch STS UBM (Quantel Medical, France). UBM bag/balloon technology was applied to measure the central anterior chamber depth (ACD) and lens vault (LV) in horizontal and vertical orientation in sitting and supine positions, angle opening distance (AOD500), trabecular iris angle (TIA) and iris lens angle (ILA) in four quadrants: superior, inferior, nasal, and temporal.

Results

We found no significant difference in ACD between sitting and supine positions (p = 0.053); LV was significantly greater in the supine position (p < 0.001); AOD500 in superior and inferior quadrants were significantly longer in the sitting position (p = 0.001; p < 0.001); TIA in superior and inferior quadrants was significantly greater in the sitting position (p < 0.001; p < 0.001), and TIAmax-min was significantly smaller in the sitting position (p = 0.001); ILA in temporal quadrant was significantly larger in the sitting position (p = 0.015) and ILAmax-min was significantly smaller in the sitting position (p < 0.001).

Conclusion

The anterior chamber angle was narrower and the lens was positioned more anteriorly in the supine than in the sitting position in cortical age-related cataract. Different positions may affect the angle configuration and the relative space of lens through different directions of mechanics and modes of action.

Predicting the risk of clinically significant intraocular lens tilt and decentration in vitrectomized eyes

PURPOSE

To identify predictors and develop a prognostic nomogram for clinically significant intraocular lens (IOL) tilt and decentration in vitrectomized eyes.

SETTING

Zhongshan ophthalmic center, Guangzhou, China.

DESIGN

Prospective observational study.

METHODS

Patients with previous pars plana vitrectomy who underwent phacoemulsification with IOL implantation were enrolled in this study. The tilt and decentration of the lens and IOL were assessed by a swept-source anterior segment optical coherence tomography (CASIA2). Multiple logistic regression analysis and prognostic nomogram models were used to explore factors associated with clinically significant IOL tilt and decentration (defined as tilt ≥7 degrees and decentration ≥0.4 mm).

RESULTS

375 patients (375 eyes) with a mean age of 56.1 ± 9.81 years were included. Lens tilt (odds ratio [OR] = 1.44), lens decentration (OR = 1.74), lens diameter (OR = 0.49), and hydrophilic IOL (OR = 2.36) were associated with IOL tilt over 7 degrees (all P &amp;lt; .05). Lens tilt (OR = 1.24), lens decentration (OR = 2.30), and incomplete capsulorhexis-IOL overlap (OR = 2.44) increased the risk of IOL decentration over 0.4 mm (all P &amp;lt; .05). Preoperative lens tilt together with lens decentration was identified as the strongest predictor of incident clinically significant IOL tilt (area under the curve [AUC] = 0.82, 95% CI, 0.76-0.88) and decentration (AUC: 0.84, 95% CI, 0.78-0.89), and the nomogram was constructed accordingly.

CONCLUSIONS

The tilt and decentration of the crystalline lens, hydrophilic IOL, and incomplete capsulorhexis-IOL overlap were risk factors for clinically significant IOL misalignment. Clinicians could use a prognostic nomogram model based on the preoperative lens position to make a strategy for higher-risk patients.

Ocular Biocompatibility of a Nitinol Capsular Tension Ring (CTR)

Introduction: The biocompatibility of nitinol in the human body has extensively been demonstrated. Although nitinol is already being used for intraocular surgeries such as lens fragmentation and foreign body extraction, little is known about its intracapsular, long-term behavior. The purpose of this study is to evaluate the long-term uveal and capsular biocompatibility of a nitinol CTR placed in the capsular bag after cataract surgery in an animal model.

Method: After approval of the study by the Institutional Animal Care and the Ethics Committee, bilateral phacoemulsification was performed in 6 rabbits; 1 eye received a nitinol CTR and the other a control polymethylmethacrylate (PMMA) open-ended ring. Ophthalmic evaluation for the presence of infections in all 12 eyes was performed after 7 days, 4 weeks, 3 months, and 6 months follow-up period. After a follow-up period of 6 months, the eyes were enucleated, and a histopathologic evaluation was performed.

Results: Neither of the groups showed any clinical signs of posterior capsule opacification (PCO) or inflammation. The nitinol group showed slightly less inflammation during histopathologic examination compared to the PMMA group.

No biocompatibility issues have been observed in this animal study.

Conclusions: There were no histological differences between eyes implanted with nitinol and eyes implanted with PMMA rings. Nitinol has proven to show high biocompatibility when implanted in the capsular bag of the rabbit eye.

Intrascleral Intraocular Lens Fixation Preserving the Lens Capsule in Cases of Cataract with Insufficient Zonular Support

Purpose

To report our modified simple technique for optic capture and the clinical results of intrascleral IOL fixation preserving the lens capsule, without vitrectomy, in cases of cataract with insufficient zonular support to stabilize the intraocular lens (IOL).

Patients and Methods

In 37 eyes of 25 patients with phacodonesis and two or more risk factors for progressive zonular insufficiency, we inserted a CTR to support the capsule and zonules during cataract surgery and IOL fixation; an optic was inserted into the lens capsule, and a haptic was fixed in the scleral tunnel without vitrectomy. In all cases, anterior or total vitrectomy was not needed.

Results

The postoperative mean (± standard deviation) tilt and decentration of the implanted IOL did not change from 6 to 12 months (6.77 ± 3.15° to 6.33 ± 3.38° and 0.60 ± 0.30 to 0.61 ± 0.35 mm, respectively). We encountered no late IOL dislocation and no retinal complications, including retinal breaks or cystoid macular oedema, postoperatively (follow-up = 21.1 ± 5.2 months).

Conclusion

Our modified techniques preclude the need for vitrectomy. If the lens capsule can be preserved using a CTR, our modified technique can be used to stabilize IOL.