Endothelial Cell Loss and Induced Astigmatism After Wound-directed and Wound-assisted IOL Injection

Endothelial Cell Loss and Surgically Induced Astigmatism After 2.2 mm Wound Assisted vs 2.4 mm Wound-Directed Clear Corneal Incisions for Intraocular Lens Insertion During Cataract Surgery

The purpose of this study is to determine if there is any difference in astigmatism (eye surface curvature) or corneal endothelial cell density (the inner cell lining of the eye surface) after two different methods for inserting a lens during cataract surgery.

Study Overview

• Status: Completed
• Conditions: Cataracts; Cataract Surgery
• Intervention / Treatment: Procedure: Lens insertion during cataract surgery

Detailed Description

Cataract surgery (removal of a cloudy lens) is currently performed through increasingly smaller incisions. Bimanual surgery, where two instruments are used to remove the lens, is performed through two 1.4 mm incisions. Typically, one of these incisions is enlarged to 2.2 or 2.4 mm in order that the IOL (artificial lens) can be inserted into the eye. Surgeons insert these lenses by placing a lens injector cartridge completely into the eye (wound-directed insertion) or by placing only the tip inside the incision (wound-assisted insertion). While wound-assisted insertion can be performed through slightly smaller incisions (2.2 mm versus 2.4 mm for wound-directed insertion), both methods of insertion cause some incision enlargement. There is some evidence that wound-assisted insertion can cause very short-term pressure within the eye to go up. Neither method is considered inferior or superior to the other, and the primary investigator (Dr. Kenneth Cohen) routinely uses both methods.

No studies have directly compared wound-healing characteristics between these two methods. We seek to compare differences in:

1. Surgically-induced astigmatism (changes in the corneal curvature from cataract surgery incisions.
2. Endothelial cell density loss. Endothelial cells line the inside surface of the cornea, and their overall density can be decreased by cataract surgery.
3. Best-corrected vision after surgery
4. Sizes of the incisions after lens injection

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Chapel Hill, North Carolina, United States, 27599
      • Kittner Eye Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Eligible patients include those who undergo uncomplicated cataract extraction surgery and IOL implantation by KLC.

Exclusion Criteria: Patients who:

1. suffer from diabetes and have more than mild background diabetic retinopathy,
2. have a history of intraocular surgery,
3. have a history of ocular trauma,
4. have known pathology of the cornea,
5. have a history of intraocular inflammation,
6. are unable to understand English,
7. are decisionally impaired,
8. are currently incarcerated, or
9. are less than 18 years of age.

No exclusions will be made on the basis of gender, ethnicity, or race.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Wound-assisted lens injection; Wound-assisted lens injection is considered neither superior or inferior to wound-directed lens injection.	Procedure: Lens insertion during cataract surgery; After cataract removal during cataract surgery, a lens needs to be injected into the eye. Both arms are routinely used but different methods for injecting the lens.
Active Comparator: Wound-directed lens injection; Wound-directed lens injection is neither considered superior nor inferior to wound-assisted lens injection.	Procedure: Lens insertion during cataract surgery; After cataract removal during cataract surgery, a lens needs to be injected into the eye. Both arms are routinely used but different methods for injecting the lens.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Surgically induced astigmatism	measured by topography at 1 month post operative visit	1 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Endothelial cell loss	As measured by specular microscopy	one month
Best corrected visual acuity	By manifest refraction	one month
Final incision size	measured with incision gauges before and after lens injection.	intraoperatively (day #0)

Collaborators and Investigators

• Sponsor: University of North Carolina, Chapel Hill
• Investigators: Principal Investigator: Kenneth Cohen, MD, UNC dept. of ophthalmology

Publications and helpful links

General Publications

• Tsuneoka H, Hayama A, Takahama M. Ultrasmall-incision bimanual phacoemulsification and AcrySof SA30AL implantation through a 2.2 mm incision. J Cataract Refract Surg. 2003 Jun;29(6):1070-6. doi: 10.1016/s0886-3350(03)00076-2.
• Kamae KK, Werner L, Chang W, Johnson JT, Mamalis N. Intraocular pressure changes during injection of microincision and conventional intraocular lenses through incisions smaller than 3.0 mm. J Cataract Refract Surg. 2009 Aug;35(8):1430-6. doi: 10.1016/j.jcrs.2009.03.038.
• Osher RH. Microcoaxial phacoemulsification Part 2: clinical study. J Cataract Refract Surg. 2007 Mar;33(3):408-12. doi: 10.1016/j.jcrs.2006.10.055.
• Kohnen T, Klaproth OK. Incision sizes before and after implantation of SN60WF intraocular lenses using the Monarch injector system with C and D cartridges. J Cataract Refract Surg. 2008 Oct;34(10):1748-53. doi: 10.1016/j.jcrs.2008.06.031.
• Ventura AC, Walti R, Bohnke M. Corneal thickness and endothelial density before and after cataract surgery. Br J Ophthalmol. 2001 Jan;85(1):18-20. doi: 10.1136/bjo.85.1.18.
• Masket S, Wang L, Belani S. Induced astigmatism with 2.2- and 3.0-mm coaxial phacoemulsification incisions. J Refract Surg. 2009 Jan;25(1):21-4. doi: 10.3928/1081597X-20090101-04.

Study record dates

Study Major Dates

• Study Start: April 1, 2010
• Primary Completion (Actual): November 1, 2010
• Study Completion (Actual): November 1, 2010

Study Registration Dates

• First Submitted: November 29, 2010
• First Submitted That Met QC Criteria: November 30, 2010
• First Posted (Estimate): December 1, 2010

Study Record Updates

• Last Update Posted (Estimate): December 1, 2010
• Last Update Submitted That Met QC Criteria: November 30, 2010
• Last Verified: November 1, 2010

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Refractive Errors; Cataract; Astigmatism
• Other Study ID Numbers: 10-0435