Capsular Tension Ring With Hydrophilic Versus Hydrophobic Intraocular Lenses (CTR-IOL-3ARM)
Outcomes of Hydrophilic Intraocular Lens Implantation With and Without a Capsular Tension Ring Versus Hydrophobic Intraocular Lens Implantation Alone: A Randomized Controlled Trial
This study compares three approaches to cataract surgery. Cataract surgery involves removing the eye's cloudy natural lens and replacing it with an artificial intraocular lens (IOL) to restore clear vision. IOLs are made from different materials, most commonly a "hydrophilic" (water-attracting) acrylic or a "hydrophobic" (water-repelling) acrylic. Hydrophilic lenses are generally easier and less expensive to use, but have been linked in past research to a higher chance of the lens capsule becoming cloudy again after surgery (posterior capsule opacification, or PCO), sometimes requiring a follow-up laser treatment. Hydrophobic lenses tend to have lower rates of this problem but can cost more.
A capsular tension ring (CTR) is a small flexible ring that can be placed inside the eye at the time of surgery to help hold the lens capsule in a stable, round shape. This study asks whether adding a CTR when a hydrophilic lens is used can reduce the disadvantages usually seen with that lens material.
600 adult patients (ages 50-80) undergoing cataract surgery at three hospitals in Egypt were randomly assigned to one of three groups: (1) a hydrophilic lens plus a CTR, (2) a hydrophobic lens alone (the common comparison approach), or (3) a hydrophilic lens alone without a CTR. Patients were followed for 24 months, and researchers compared vision, glasses prescription accuracy, lens position, capsule clouding, need for laser treatment, and surgical complications between the groups.
The results showed that adding a CTR to a hydrophilic lens produced results very similar to using a hydrophobic lens alone. In contrast, using a hydrophilic lens without a CTR resulted in worse vision, less accurate glasses prescriptions, more lens shifting or tilting, more capsule clouding, a higher need for laser treatment, and more complications compared with the hydrophobic lens. These findings suggest that adding a CTR may be a simple, low-cost way to improve outcomes when a hydrophilic lens is used for cataract surgery.
Aperçu de l'étude
Statut
Les conditions
Description détaillée
Background and rationale: Phacoemulsification with intraocular lens (IOL) implantation is the standard treatment for age-related cataract. IOL material (hydrophilic versus hydrophobic acrylic) is a recognized determinant of long-term capsular biocompatibility, with hydrophobic acrylic lenses generally associated with lower rates of posterior capsule opacification (PCO) and reduced need for neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy compared with hydrophilic acrylic lenses. Capsular tension rings (CTRs) are polymethyl methacrylate devices that stabilize the capsular bag equator and have been proposed to mitigate capsular contraction, lens decentration, and PCO, independent of IOL material. Prior comparative work has generally examined either IOL material effects or CTR effects in isolation, or has compared a composite intervention (hydrophilic IOL plus CTR) against a hydrophobic IOL alone, without a design capable of isolating the CTR's independent contribution.
Objectives: To compare visual, refractive, anatomical (IOL position and posterior capsule opacification), and safety outcomes among three approaches to routine cataract surgery: (1) hydrophilic acrylic IOL implantation combined with a CTR (Group A); (2) hydrophobic acrylic IOL implantation alone (Group B); and (3) hydrophilic acrylic IOL implantation alone, without a CTR (Group C). The inclusion of Group C, using the same hydrophilic IOL model as Group A but without CTR insertion, was designed specifically to allow assessment of the CTR's independent contribution when compared against Group A, in addition to the material-based comparisons of Groups A and C against Group B.
Design: Prospective, randomized, parallel-group, three-arm controlled trial conducted at three tertiary ophthalmology centers in Egypt (Zagazig University Hospital, Benha University Hospital, and Al-Azhar University Hospital). Eligible adults aged 50-80 years with visually significant age-related cataract (LOCS III grade >=3) were randomized 1:1:1 using a computer-generated allocation sequence, with allocation concealment via sealed opaque envelopes opened intraoperatively. Outcome assessors and data analysts were blinded to treatment allocation; operating surgeons were not blinded due to the nature of the intervention.
Interventions: All participants underwent standardized phacoemulsification via a 2.2 mm clear corneal incision with a ~5.5 mm continuous curvilinear capsulorhexis. Group A received a hydrophilic acrylic IOL (Eyecryl, Biotech Healthcare, India) plus a polymethyl methacrylate CTR (Auroring CTR 11, Aurolab, India). Group B received a hydrophobic acrylic IOL (AcrySof IQ, Alcon Laboratories, USA) without a CTR. Group C received the same hydrophilic acrylic IOL as Group A, without CTR insertion.
Outcomes: Primary outcomes were best-corrected visual acuity (logMAR) and manifest spherical equivalent refractive error at 24 months, with longitudinal assessment at 1, 3, 6, 12, 18, and 24 months. Secondary outcomes included posterior capsule opacification grade (slit-lamp retroillumination, graded per Aslam et al.), Nd:YAG capsulotomy rate, IOL centration and tilt (anterior segment optical coherence tomography), and intraoperative and postoperative complications (posterior capsule rupture, zonular dialysis, vitreous loss, iris trauma, cystoid macular edema, intraocular pressure elevation, corneal edema, and endophthalmitis).
Follow-up: Scheduled visits at day 1, week 1, and months 1, 3, 6, 12, 18, and 24 postoperatively, with the 24-month visit representing the final prespecified assessment.
Statistical analysis: Continuous variables were compared across groups using one-way ANOVA or Kruskal-Wallis testing as appropriate, with post-hoc pairwise comparisons for Group A vs. Group B and Group C vs. Group B. Categorical variables were compared using chi-square or Fisher's exact test. Repeated-measures ANOVA assessed longitudinal group x time interactions for visual and refractive outcomes.
Type d'étude
Inscription (Réel)
Phase
- N'est pas applicable
Contacts et emplacements
Lieux d'étude
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Benha
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Banhā, Benha, Egypte, 13111
- Benha University
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Critères de participation
Critère d'éligibilité
Âges éligibles pour étudier
Accepte les volontaires sains
Sexes éligibles pour l'étude
La description
Inclusion Criteria:
- Age 50-80 years
- Visually significant age-related cataract, defined as nuclear opacity grade >=3 according to the Lens Opacities Classification System III (LOCS III), graded preoperatively under standardized mydriasis via slit-lamp biomicroscopy
- Clear cornea
- Adequate pupillary dilation
- Anatomically normal capsular bag with no evidence of zonular weakness
- No ocular comorbidities expected to affect visual or refractive outcomes
Exclusion Criteria:
- Previous intraocular surgery
- Ocular trauma
- Pseudoexfoliation syndrome
- Posterior polar cataract
- Zonular instability
- Complicated cataract
- Active intraocular inflammation
- Retinal or optic nerve pathology
- Anticipated need for additional capsular support devices beyond the study protocol
Plan d'étude
Comment l'étude est-elle conçue ?
Détails de conception
- Objectif principal: Traitement
- Répartition: Randomisé
- Modèle interventionnel: Affectation parallèle
- Masquage: Seul
Armes et Interventions
Groupe de participants / Bras |
Intervention / Traitement |
|---|---|
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Expérimental: U.S. flag An official website of the United States government Here's how you know Skip to main page
Phacoemulsification with implantation of a hydrophilic acrylic intraocular lens (Eyecryl, Biotech Healthcare, India) combined with insertion of a polymethyl methacrylate capsular tension ring (Auroring CTR 11, Aurolab, India). |
Foldable hydrophilic acrylic intraocular lens implanted in the capsular bag following phacoemulsification. Polymethyl methacrylate capsular tension ring (overall diameter 13.0 mm, compressed diameter 11.0 mm) inserted into the capsular bag to distribute equatorial zonular forces and maintain capsular bag contour. |
|
Comparateur actif: Group B: Hydrophobic IOL alone
Phacoemulsification with implantation of a hydrophobic acrylic intraocular lens (AcrySof IQ, Alcon Laboratories, USA), without a capsular tension ring. |
Foldable hydrophobic acrylic intraocular lens implanted in the capsular bag following phacoemulsification. |
|
Expérimental: Group C: Hydrophilic IOL alone
Phacoemulsification with implantation of the same hydrophilic acrylic intraocular lens used in Group A (Eyecryl, Biotech Healthcare, India), without capsular tension ring insertion. |
Foldable hydrophilic acrylic intraocular lens implanted in the capsular bag following phacoemulsification. |
Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
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Best-corrected visual acuity (BCVA)
Délai: 24 months postoperatively
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Best-corrected visual acuity measured in logMAR units, assessed longitudinally at 1, 3, 6, 12, 18, and 24 months, with between-group comparison at 24 months as the primary efficacy endpoint. |
24 months postoperatively
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Mesures de résultats secondaires
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
|
Manifest spherical equivalent refractive error
Délai: 24 months postoperatively
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Manifest spherical equivalent refractive error (diopters), assessed longitudinally at 1, 3, 6, 12, 18, and 24 months, with between-group comparison at 24 months as the primary efficacy endpoint. Proportion of eyes within +/-0.5 D and +/-1.0 D of target refraction was also assessed at 24 months. |
24 months postoperatively
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Collaborateurs et enquêteurs
Parrainer
Dates d'enregistrement des études
Dates principales de l'étude
Début de l'étude (Réel)
Achèvement primaire (Réel)
Achèvement de l'étude (Réel)
Dates d'inscription aux études
Première soumission
Première soumission répondant aux critères de contrôle qualité
Première publication (Réel)
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Réel)
Dernière mise à jour soumise répondant aux critères de contrôle qualité
Dernière vérification
Plus d'information
Termes liés à cette étude
Autres numéros d'identification d'étude
- ZU-BU-AU-CTR-IOL-3ARM-2023
Informations sur les médicaments et les dispositifs, documents d'étude
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Étudie un produit d'appareil réglementé par la FDA américaine
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