Surgical Treatment of Concurrent Cataract and Primary Pterygium

The recruitment status of this study is unknown because the information has not been verified recently.
Verified July 2010 by Hospital Authority, Hong Kong.
Recruitment status was  Recruiting
Sponsor:
Information provided by:
Hospital Authority, Hong Kong
ClinicalTrials.gov Identifier:
NCT00563277
First received: November 21, 2007
Last updated: July 6, 2010
Last verified: July 2010
  Purpose

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.


Condition Intervention
Pterygium
Cataract
Lenses, Intraocular
Procedure: combined pterygium and cataract operation
Procedure: pterygium excision followed by cataract operation

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Surgical Treatment of Concurrent Cataract and Primary Pterygium: A Randomized Control Trial

Resource links provided by NLM:


Further study details as provided by Hospital Authority, Hong Kong:

Primary Outcome Measures:
  • final refraction deviation from target [ Time Frame: 1 and 3 months post cataract operation ]

Secondary Outcome Measures:
  • change of IOL power from pre-pterygium estimated power [ Time Frame: 1 and 3 months post pterygium excision ]

Estimated Enrollment: 75
Study Start Date: October 2004
Estimated Study Completion Date: December 2006
  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Criteria

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00563277

Contacts
Contact: Lulu Cheng, Dr (852) 2632 2878 chenglu@i-cable.com

Locations
China
Prince of Wales Hospital Recruiting
Hong Kong, China
Sub-Investigator: Alvin Young, Dr         
Sub-Investigator: Gloria Leung, Dr         
Sub-Investigator: Arthur Cheng, Prof         
Alice Ho Miu Ling Nethersole Hospital Recruiting
Hong Kong, China
Hong Kong Eye Hospital Recruiting
Hong Kong, China
Sub-Investigator: Dennis Lam, Prof         
Sponsors and Collaborators
Hospital Authority, Hong Kong
Investigators
Principal Investigator: Lulu Cheng, Dr Department of DOVS, Prince of Wales Hospital/ The Chinese University of Hong Kong
  More Information

Additional Information:
No publications provided

ClinicalTrials.gov Identifier: NCT00563277     History of Changes
Other Study ID Numbers: CRE-2004.274-T, HARECCTR0500012
Study First Received: November 21, 2007
Last Updated: July 6, 2010
Health Authority: Hong Kong: Ethics Committee

Keywords provided by Hospital Authority, Hong Kong:
Pterygium
Cataract
Intraocular lens power calculation accuracy

Additional relevant MeSH terms:
Pterygium
Cataract
Conjunctival Diseases
Eye Diseases
Lens Diseases

ClinicalTrials.gov processed this record on July 23, 2014