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

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Sun Yat-sen University

Status

Completed

Conditions

Cataract

Treatments

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

Study type

Interventional

Funder types

Other

Identifiers

NCT02609997
CCPMOH2010-China9

Details and patient eligibility

About

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.

Full 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.

Enrollment

65 patients

Sex

All

Ages

60 to 85 years old

Volunteers

No Healthy Volunteers

Inclusion criteria

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

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

Trial design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

Single Blind

65 participants in 2 patient groups

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

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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