Impact of Capsular Tension Ring Implantation on Intraocular Lens Position

Study Overview
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Brief Summary
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This is a randomized controlled trial to investigate the effect of capsular tension ring (CTR) implantation on intraocular lens (IOL) tilt and decentration in cataract patients with high myopia.

Detailed Description
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Exact positioning and alignment of the IOL with the visual axis are the prerequisites of high-quality visual performance after cataract surgery. A certain degree of IOL tilt and decentration occur after uneventful cataract surgery, most of which are clinically tolerant. However, the relatively large capsular bag volume, zonular weakness, and vitreous liquefaction in cataract patients with high myopia may increase the IOL position instability, such as tilt, decentration and even dislocation, leading to the deterioration of visual function. Thus, how to improve the long-term stability of IOL position in high myopic cataract patients is an urgent issue to be addressed. Previous studies have shown that CTR implantation during cataract surgery can increase the IOL stability in patients with normal axial length; however, its impact on IOL position of cataract patients with high myopia remains unclear. In this randomized clinical trial, patients who meet the inclusion criteria will be divided into three layers according to the axial length: (1)26mm≤AL<28mm (2)28mm≤AL<30mm (3)AL≥30mm We are going to recruit 186 patients in total, with 62 patients in each layer. Patients on each layer will be randomly divided into experimental group (CTR implantation) and control group (only IOL implantation). If both eyes of a patient meet the inclusion criteria, only the first operated eye is included in the statistics analysis. All included patients will be followed up at 1 week, 1 month, 3 months, 6 months, and 1 year postoperatively. Visual acuity, IOL tilt, IOL decentration, posterior capsule attachment with IOL, anterior capsule contraction, posterior capsular opacification, and visual quality will be measured and compared between the experimental group and the control group at different timepoints.

Official Title
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Impact of Capsular Tension Ring Implantation on Intraocular Lens Tilt and Decentration in Cataract Patients With High Myopia: a Randomized Controlled Trial

Conditions
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Cataract, High Myopia

Intervention / Treatment
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* Procedure: phacoemulsification combined with IOL and CTR implantation
* Procedure: phacoemulsification combined with IOL implantation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: > 18 years old; axis length≥26mm; Visually significant cataract; The patient is willing and able to complete all necessary follow-ups and examinations. Exclusion Criteria: Intraoperative or postoperative complications: such as intraoperative posterior capsular rupture, zonular dehiscence, secondary glaucoma, endophthalmitis, etc.; Other ocular comorbidity: such as keratopathy, glaucoma, uveitis, retinopathy, lens dislocation and ocular trauma, etc.; History of intraocular surgery; Severe systemic diseases: such as severe hypertension, diabetes, heart disease, Alzheimer's, Parkinson, etc.; Any condition that the study physician considers to be an impediment to the clinical trial.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: IOL plus CTR Patients will undergo phacoemulsification combined with IOL and CTR implantation.<br> | Procedure: phacoemulsification combined with IOL and CTR implantation<br>* Device: CTR (276001G； OPHTEC BV, Netherlands) Device: IOL (920H; Rayner Intracular Lenses Limited，Hove，East Sussex，UK) All patients undergo uneventful phacoemulsification by a 3.0 mm temporal transparent corneal incision using Centurion Vision System (Alcon Laboratories, Fort Worth, TX, USA). After the nucleus and cortex are removed, a capsular tension ring is implanted in the capsular bag and then IOL is implanted.<br>|
| Placebo Comparator: single IOL Patients will undergo phacoemulsification combined with IOL implantation.<br> | Procedure: phacoemulsification combined with IOL implantation<br>* Device: IOL (920H; Rayner Intracular Lenses Limited，Hove，East Sussex，UK) All patients undergo uneventful phacoemulsification by a 3.0 mm temporal transparent corneal incision using Centurion Vision System (Alcon Laboratories, Fort Worth, TX, USA). After the nucleus and cortex are removed, IOL is implanted in the capsular bag.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| IOL dencentration | Measured by anterior segment OCT (CASIA2) | 3 months after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| IOL dencentration | Measured by anterior segment OCT (CASIA2) | Baseline (before surgery), 1 week, 1 month, 6 months, 1 year after surgery | 
| IOL tilt | Measured by anterior segment OCT (CASIA2) | Baseline (before surgery), 1 week, 1 month, 3 months, 6 months, 1 year after surgery | 
| Anterior capsule contraction | Compare the area of anterior capsule opening recorded by slit lamp photograph and analyzed by Image J software. | Baseline, 1 week, 1 month, 3 months, 6 months, 1 year after surgery | 
| Posterior capsule attachment with IOL | Measured by anterior segment OCT (CASIA2) and analyzed by Image J software. | 1 week, 1 month, 3 months, 6 months, 1 year after surgery | 
| Posterior capsular opacification | Recorded by slit lamp photograph and analyzed by EPCO2000 analysis software. | 1 week, 1 month, 3 months, 6 months, 1 year after surgery | 
| BCVA | BCVA is evaluated with ETDRS visual acuity chart. | Baseline (before surgery), 1 week, 1 month, 3 months, 6 months, 1 year after surgery | 
| Optical quality | Measured by OPD-SCAN III. | Baseline (before surgery), 1 week, 1 month, 3 months, 6 months, 1 year after surgery | 
| Visual function | Measured by visual function assessment questionnaires. | 3 months, 6 months, 1 year after surgery |