Surgical Treatment of Concurrent Cataract and Primary Pterygium
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|ClinicalTrials.gov Identifier: NCT00563277|
Recruitment Status : Unknown
Verified July 2010 by Hospital Authority, Hong Kong.
Recruitment status was: Recruiting
First Posted : November 26, 2007
Last Update Posted : July 7, 2010
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 or disease||Intervention/treatment||Phase|
|Pterygium Cataract Lenses, Intraocular||Procedure: combined pterygium and cataract operation Procedure: pterygium excision followed by cataract operation||Not Applicable|
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||75 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||None (Open Label)|
|Official Title:||Surgical Treatment of Concurrent Cataract and Primary Pterygium: A Randomized Control Trial|
|Study Start Date :||October 2004|
|Estimated Study Completion Date :||December 2006|
- final refraction deviation from target [ Time Frame: 1 and 3 months post cataract operation ]
- change of IOL power from pre-pterygium estimated power [ Time Frame: 1 and 3 months post pterygium excision ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00563277
|Contact: Lulu Cheng, Dr||(852) 2632 firstname.lastname@example.org|
|Alice Ho Miu Ling Nethersole Hospital||Recruiting|
|Hong Kong, China|
|Hong Kong Eye Hospital||Recruiting|
|Hong Kong, China|
|Sub-Investigator: Dennis Lam, Prof|
|Prince of Wales Hospital||Recruiting|
|Hong Kong, China|
|Sub-Investigator: Alvin Young, Dr|
|Sub-Investigator: Gloria Leung, Dr|
|Sub-Investigator: Arthur Cheng, Prof|
|Principal Investigator:||Lulu Cheng, Dr||Department of DOVS, Prince of Wales Hospital/ The Chinese University of Hong Kong|