Surgical Treatment of Concurrent Cataract and Primary Pterygium

July 6, 2010 updated by: Hospital Authority, Hong Kong

Surgical Treatment of Concurrent Cataract and Primary Pterygium: A Randomized Control Trial

Pterygium is known to induce with-the-rule astigmatism. The corneal curvature along the long axis of the pterygium body is flattened. The excision of pterygium will result in steepening of the cornea and reduction of astigmatism. Therefore, the effect of pterygium excision on intraocular lens (IOL) power calculation has been examined in our previous study. The study confirmed that pterygium can cause alteration of IOL power.

The determination of IOL power for cataract surgery is usually calculated from IOL formula called SRK II formula. IOL power = A - (2.5 x AL)-(0.9 x K). Variable A denotes the A-constant of the intraocular lens which is dependent on the IOL material and refractive index. Other variables for input include axial length (AL) and keratometry (K). A larger K reading will result in a lower estimated IOL power and vice versa. Previous studies have documented simultaneous cataract and pterygium operation resulted in reasonable visual outcome without adjustment of IOL power.

With the presence of a pterygium, the cornea is flattened and lead to a reduction of K value and over-estimation of calculated IOL power. This randomized controlled trial is designed to compare the refractive outcomes of sequential and simultaneous pterygium and cataract operation.

Pterygium excision should be done with various adjuvant therapies to minimize recurrence. Our previous studies reliably demonstrated limbal conjunctival graft and mitomycin C were effective methods to achieve low pterygium recurrence. We use limbal conjunctival autograft as the adjuvant therapy in the current study because this method is safer to be performed either alone or in combination with phacoemulsification. We avoid using mitomycin C as the adjuvant therapy in order to minimize the possibility of intraocular toxicity due to seepage.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Anticipated)

75

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • China
      • Hong Kong, China
        • Recruiting
        • Prince of Wales Hospital
        • Sub-Investigator:
          • Alvin Young, Dr
        • Sub-Investigator:
          • Gloria Leung, Dr
        • Sub-Investigator:
          • Arthur Cheng, Prof
      • Hong Kong, China
        • Recruiting
        • Alice Ho Miu Ling Nethersole Hospital
      • Hong Kong, China
        • Recruiting
        • Hong Kong Eye Hospital
        • Sub-Investigator:
          • Dennis Lam, Prof

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

N/A

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • >18 years old
  • Primary pterygium > 2mm across corneal limbus [Measurement made from the imaginary line of surgical limbus to the most advance edge of the visible pterygium tissue] Concurrent visually significant cataract ( BCVA < 20/70 )
  • Informed consent for both pterygium and cataract surgery

Exclusion Criteria:

  • Temporal pterygium
  • Double headed pterygium
  • Previous ocular surgery in which conjunctival-limbal graft is not feasible
  • Pterygium covering visual axis that preclude keratometric assessment
  • History of scleritis or autoimmune diseases

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
final refraction deviation from target
Time Frame: 1 and 3 months post cataract operation
1 and 3 months post cataract operation

Secondary Outcome Measures

Outcome Measure
Time Frame
change of IOL power from pre-pterygium estimated power
Time Frame: 1 and 3 months post pterygium excision
1 and 3 months post pterygium excision

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hospital Authority, Hong Kong

Investigators

  • Principal Investigator: Lulu Cheng, Dr, Department of DOVS, Prince of Wales Hospital/ The Chinese University of Hong Kong

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

October 1, 2004

Study Completion (Anticipated)

December 1, 2006

Study Registration Dates

First Submitted

November 21, 2007

First Submitted That Met QC Criteria

November 23, 2007

First Posted (Estimate)

November 26, 2007

Study Record Updates

Last Update Posted (Estimate)

July 7, 2010

Last Update Submitted That Met QC Criteria

July 6, 2010

Last Verified

July 1, 2010

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CRE-2004.274-T
  • HARECCTR0500012

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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