Surgical Treatment of Concurrent Cataract and Primary Pterygium

NCT00563277 | Unknown

• 2 other identifiers: CRE-2004.274-THARECCTR0500012
• Study Type: interventional
• Target: 75
• Locations: 1 country
• Sites: 3

Brief Summary

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.

Conditions

Pterygium; Cataract; Lenses, Intraocular

Keywords

Pterygium; Cataract; Intraocular lens power calculation accuracy

Outcome Measures

Primary Outcomes (1)

• final refraction deviation from target

  1 and 3 months post cataract operation

Secondary Outcomes (1)

• change of IOL power from pre-pterygium estimated power

  1 and 3 months post pterygium excision

Interventions

combined pterygium and cataract operation PROCEDURE

pterygium excision followed by cataract operation PROCEDURE

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• \>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

You may not qualify if:

• 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

Sponsors & Collaborators

• Hospital Authority, Hong Kong: lead

Study Sites (3)

Alice Ho Miu Ling Nethersole Hospital

Hong Kong, China

RECRUITING

Hong Kong Eye Hospital

Hong Kong, China

RECRUITING

Prince of Wales Hospital

Hong Kong, China

RECRUITING

MeSH Terms

Conditions

Pterygium; Cataract

Condition Hierarchy (Ancestors)

Conjunctival Diseases; Eye Diseases; Lens Diseases

Study Officials

• Lulu Cheng, Dr

  Department of DOVS, Prince of Wales Hospital/ The Chinese University of Hong Kong

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Lulu Cheng, Dr

CONTACT

(852) 2632 2878; chenglu@i-cable.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV

Study Record Dates

• First Submitted: November 21, 2007
• First Posted: November 26, 2007
• Study Start: October 1, 2004
• Study Completion: December 1, 2006
• Last Updated: July 7, 2010

Record last verified: 2010-07

Locations

CN (3)