Comparison of In-the-bag Stability Between Single-piece and Three-piece Intraocular Lens

Not Applicable

Completed

• Conditions: Cataract
• Interventions: Procedure: Phacomulsification lens removal cataract surgery with three-piece Intraocular lens(IOL) implantation; Procedure: Phacomulsification lens removal cataract surgery with single-piece Intraocular lens(IOL) implantation; Drug: Subconjunctival dexamethasone; Device: Viscoelastic materials; Drug: proparacaine

• Registration Number: NCT02609997
• Lead Sponsor: Sun Yat-sen University

Brief Summary

Rapid advances of cataract surgery techniques and intraocular lens (IOL) technology have enabled the transition of cataract surgery from blindness relief to refractive correction. An ideal IOL is the critical component to achieve the refractive target of cataract surgery. Biocompatibility, rate of posterior capsule opacification (PCO) and visual quality have all been suggested as the critical factors of an ideal IOL and widely investigated. Recently, stability of IOL position has also been suggested as one of those critical factors due to its close correlation with postoperative visual function. Data suggests that IOL forward movement of 0.29 mm along the visual axis is associated with -0.4D myopic shift. Wang and colleagues recently reported that 0.5mm decentration of an aspheric IOL could eliminate its aberration-correcting effect. Poor stability could even lead to IOL exchange, an additional surgery that put both surgeons and patients in pain.

As the supporting element of an IOL, the haptics are crucial to keep the IOL in place. Various haptic designs are being compared in terms of position stability of IOLs. Haptic designs of single-piece versus 3-piece are often compared because they are currently the most commonly used types. Single-piece IOLs have soft and broader haptics which are made of the same material as the optic, usually hydrophobic or hydrophilic acrylic, whereas 3-piece IOLs have rigid haptics which are made of poly methyl methacrylate (PMMA). Clinical studies comparing these haptic designs have yielded controversial results regarding their position stability in the capsular bag, which is the most recommended site for IOL fixation in an uneventful cataract surgery.

Detailed Description

Rapid advances of cataract surgery techniques and intraocular lens (IOL) technology have enabled the transition of cataract surgery from blindness relief to refractive correction. An ideal IOL is the critical component to achieve the refractive target of cataract surgery. Biocompatibility, rate of posterior capsule opacification (PCO) and visual quality have all been suggested as the critical factors of an ideal IOL and widely investigated. Recently, stability of IOL position has also been suggested as one of those critical factors due to its close correlation with postoperative visual function. Data suggests that IOL forward movement of 0.29 mm along the visual axis is associated with -0.4D myopic shift. Wang and colleagues recently reported that 0.5mm decentration of an aspheric IOL could eliminate its aberration-correcting effect. Poor stability could even lead to IOL exchange, an additional surgery that put both surgeons and patients in pain.

As the supporting element of an IOL, the haptics are crucial to keep the IOL in place. Various haptic designs are being compared in terms of position stability of IOLs. Haptic designs of single-piece versus 3-piece are often compared because they are currently the most commonly used types. Single-piece IOLs have soft and broader haptics which are made of the same material as the optic, usually hydrophobic or hydrophilic acrylic, whereas 3-piece IOLs have rigid haptics which are made of poly methyl methacrylate (PMMA). Clinical studies comparing these haptic designs have yielded controversial results regarding their position stability in the capsular bag, which is the most recommended site for IOL fixation in an uneventful cataract surgery.

Most previous studies measure the IOL position based on Purkinje reflections. The measurement is time-consuming and patients are reluctant to cooperate during image acquisition. Purkinje measurement does not detect anterior chamber depth (ACD) and as such cannot reveal the IOL position along the axis. Clinical Scheimpflug systems based on rotating Scheimpflug imaging, on the other hand, is able to acquire sufficient 3-dimensioinal data points within a reasonably short period, usually seconds. It was shown that these systems are one of the best methods to estimate IOL position. To better compare the intracapsular stability between single-piece and 3-piece IOLs, the investigators measured IOL positions with rotating Scheimpflug imaging systems and tested the visual quality of patients implanted with these IOLs.

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study Start: 2012-09
• Primary Completion: 2012-12
• Study Completion: 2012-12
• Status Verified: 2015-11
• Study First Submitted: 2015-11-14
• Study First Submitted QC: 2015-11-18
• Last Update Submitted: 2015-11-18
• Study First Posted: 2015-11-20
• Last Update Posted: 2015-11-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 65

Inclusion Criteria

• diagnosis of bilateral age-related cataract and age between 60 to 85 years

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Exclusion Criteria

• vision-impairing diseases other than cataract, severe refractive error (Preoperative spherical equivalent of either eye >-6.00D or +5.00D)
• history of ocular trauma, past refractive surgery or other ophthalmic surgery, capsular or zonular disorders that might affect the post-operative centration of IOLs
• surgical complications including severe hyphema, iris injury, repeated IOL implantation
• unable to achieve in-the-bag implantation of IOL, corneal sutures during surgery

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Three-piece IOL Group	Phacomulsification lens removal cataract surgery with three-piece Intraocular lens(IOL) implantation	Age-related cataract patients receive in-the-bag implantation of a three-piece IOL
Three-piece IOL Group	Subconjunctival dexamethasone	Age-related cataract patients receive in-the-bag implantation of a three-piece IOL
Single-piece IOL Group	Subconjunctival dexamethasone	Age-related cataract patients receive in-the-bag implantation of a single-piece IOL
Three-piece IOL Group	Viscoelastic materials	Age-related cataract patients receive in-the-bag implantation of a three-piece IOL
Single-piece IOL Group	Phacomulsification lens removal cataract surgery with single-piece Intraocular lens(IOL) implantation	Age-related cataract patients receive in-the-bag implantation of a single-piece IOL
Single-piece IOL Group	Viscoelastic materials	Age-related cataract patients receive in-the-bag implantation of a single-piece IOL
Single-piece IOL Group	proparacaine	Age-related cataract patients receive in-the-bag implantation of a single-piece IOL
Three-piece IOL Group	proparacaine	Age-related cataract patients receive in-the-bag implantation of a three-piece IOL

Primary Outcome Measures

Name	Time	Method
The grade of in-the-bag stability between single-piece intraocular lenses (IOLs) and three-piece intraocular lenses(IOLs)	3 months after the surgery

Secondary Outcome Measures

Name	Time	Method
The visual acuity between single-piece intraocular lenses (IOLs) and three-piece intraocular lenses(IOLs)	3 months after the surgery

Trial Locations

Locations (1)

Zhognshan Ophthalmic Center, Sun Yat-sen University; 🇨🇳 Guangzhou, Guangdong, China