Intraocular Lens-shell Technique in Phacoemulsification

Intraocular Lens-Shell Technique: An Adjustment of Surgical Procedure Makes Differences in Treating Dense Nucleus Cataract

In this study, the investigators introduce a surgical procedure called "IOL-shell technique" in the purpose of reduce complications of surgeries for dense cataract, and report a prospective randomized controlled study aiming at assessing efficacy and safety of the IOL-shell technique, which showed that the new procedure offered a safer way for hard cataract surgery over the conventional phacoemulsification procedure without compromise in efficacy.

Study Overview

• Status: Completed
• Conditions: Cataract; Pseudoaphakia
• Intervention / Treatment: Procedure: IOL-shell technique; Procedure: Conventional procedure

Detailed Description

A Prospective, randomized controlled study of 80 eyes with dense nucleus were enrolled. Patients were assigned to two groups: Group I: IOL was traditionally implanted after all nuclear fragments were completely removed, while in Group II, IOL was innovatively implanted in the bag before last residual nuclear fragment was removed. This novel adjusted surgical procedure, featured by using IOL as a protective barrier (named "IOL-shell technique"), not just as a refractive alternative, was conceptual different from the traditional step-by-step procedure. Clinical examinations including uncorrected visual acuity, central corneal thickness (CCT), temporal clear corneal thickness and the corneal endothelial cell density were carried out.

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510060
      • Zhongshan Ophthalmic Center,Sun Yat-Sen University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years to 90 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Aged 50 years or above
• Dense cataract cases were defined as eyes in which the nuclear color was graded IV or V according to the Lens Opacities Classification System III (LOCS III). Special attention was paid in selecting cases without apparent posterior cortical layer.
• No central corneal opacification
• Pupil diameter >= 7 mm after full pharmacological dilation in preoperative assessment
• A preoperative central endothelial cell count of >= 1500 cells/mm2.

Exclusion Criteria:

• Participants with previous intraocular surgery
• Abnormal lens zonules
• Glaucoma
• High myopia (>-6.0 Diopters)
• Pseudoexfoliation
• Uveitis
• Diabetes mellitus
• Those who were not able to come for follow-up visits.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: IOL-shell technique; In this group, before the emulsification of the last nuclear fragment, cohesive viscoelastic material was injected below the nuclear fragment and a foldable IOL was implanted into the well inflated capsular bag posterior to the nuclear fragment. The remaining last piece of nuclear fragment was then emulsified and removed within the capsular bag.	Procedure: IOL-shell technique; Phacoemulsification was performed with the same device and handpieces, using the same phaco chop technique as in the conventional procedure group. What was different was that before the emulsification of the last nuclear fragment, cohesive viscoelastic material was injected below the nuclear fragment and a foldable IOL was implanted into the well inflated capsular bag posterior to the nuclear fragment. The remaining last piece of nuclear fragment was then emulsified and removed within the capsular bag.
Active Comparator: Conventional procedure; In this group, a Sensar IOL (AMO Laboratories) was implanted in the capsular bag with the injector system after the lens material was completely removed. The nuclear fragmentation was performed using the Phaco-chop technique, which was then followed by ultrasound emulsification of the nuclear fragments piece by piece. Due to lack of cortical shell within the capsular bag, special care was taken to carry out the emulsification of the last nuclear fragment at a relatively more anterior anatomical position between the iris plan and the anterior chamber.	Procedure: Conventional procedure; In this procedure, a IOL was not implanted until all the nuclear fragments were removed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central corneal endothelial cell loss	Central corneal endothelial cell loss was calculated by subtracting postoperative corneal endothelial cell density from the preoperative baseline level.	one month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
central cornea thickness	The temporal corneal thickness and central corneal thickness were measured using the manual measurement scale in the scanning pictures of anterior segment optical coherence tomography preoperatively and at each postoperative visit.	one month

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
un-corrected visual acuity	The un-corrected visual acuity was measured and recorded using an Early Treatment Diabetic Retinopathy Study chart both before operation and at the 1st, 7th and 30th day after operation.	one month

Collaborators and Investigators

• Sponsor: Sun Yat-sen University
• Collaborators: National Natural Science Foundation of China
• Investigators: Study Chair: Yizhi Liu, Ph.D., Zhongshan Ophthalmic Center, Sun Yat-sen University

Publications and helpful links

General Publications

• Shah PA, Yoo S. Innovations in phacoemulsification technology. Curr Opin Ophthalmol. 2007 Feb;18(1):23-6. doi: 10.1097/ICU.0b013e328011f9d0.
• Luo L, Lin H, He M, Congdon N, Yang Y, Liu Y. Clinical evaluation of three incision size-dependent phacoemulsification systems. Am J Ophthalmol. 2012 May;153(5):831-839.e2. doi: 10.1016/j.ajo.2011.10.034. Epub 2012 Feb 4.
• Hwang HS, Kim EC, Kim MS. Drill-and-crack technique for nuclear disassembly of hard nucleus. J Cataract Refract Surg. 2010 Oct;36(10):1627-30. doi: 10.1016/j.jcrs.2010.08.003.
• Luo L, Lin H, Chen W, Qu B, Zhang X, Lin Z, Chen J, Liu Y. Intraocular lens-shell technique: adjustment of the surgical procedure leads to greater safety when treating dense nuclear cataracts. PLoS One. 2014 Nov 17;9(11):e112663. doi: 10.1371/journal.pone.0112663. eCollection 2014.

Helpful Links

• Homepage of Zhongshan Ophthalmic Center

Study record dates

Study Major Dates

• Study Start: December 1, 2011
• Primary Completion (Actual): June 1, 2013
• Study Completion (Actual): June 1, 2013

Study Registration Dates

• First Submitted: May 12, 2014
• First Submitted That Met QC Criteria: May 13, 2014
• First Posted (Estimate): May 14, 2014

Study Record Updates

• Last Update Posted (Estimate): June 9, 2014
• Last Update Submitted That Met QC Criteria: June 6, 2014
• Last Verified: June 1, 2014

More Information

Terms related to this study

• Keywords: phacoemulsification; intraocular lens; dense cataract; lens-shell technique
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: CCPMOH2010-China5