Variability of Pentacam-derived Back Elevation Measurements in Keratoconus and Cross-linked Corneas

This study has been completed.

Sponsor:

Information provided by (Responsible Party):

Georgios Labiris, Democritus University of Thrace

ClinicalTrials.gov Identifier:

NCT01471873

First received: November 9, 2011

Last updated: November 10, 2011

Last verified: November 2011

History of Changes

Tracking Information
First Received Date ^ICMJE	November 9, 2011
Last Updated Date	November 10, 2011
Start Date ^ICMJE	March 2011
Primary Completion Date	September 2011 (final data collection date for primary outcome measure)
Current Primary Outcome Measures ^ICMJE (submitted: November 10, 2011)	Variability of posterior corneal surface elevation measurements within and between sessions and within and between observers. [ Time Frame: 2 weeks ] [ Designated as safety issue: No ] The Pentacam Classic (Oculus Optikgerate GmbH, Heidelberg, Germany, software version 1.14r04) was used for the sake of the study. Three consecutive scans were obtained by two experienced operators for the assessment of intrasession and interobserver variability. The same procedure was repeated within two weeks for the assessment of intersession variability.Bland-Altman plots were used to evaluate agreement between the 2 operators. The reproducibility of all measurements was evaluated by means of the intraclass correlation coefficient(ICC).
Original Primary Outcome Measures ^ICMJE	Same as current
Change History	Complete list of historical versions of study NCT01471873 on ClinicalTrials.gov Archive Site
Current Secondary Outcome Measures ^ICMJE	Not Provided
Original Secondary Outcome Measures ^ICMJE	Not Provided
Current Other Outcome Measures ^ICMJE	Not Provided
Original Other Outcome Measures ^ICMJE	Not Provided

Descriptive Information
Brief Title ^ICMJE	Variability of Pentacam-derived Back Elevation Measurements in Keratoconus and Cross-linked Corneas
Official Title ^ICMJE	Variability of Pentacam-derived Back Elevation Measurements in Keratoconus and Cross-linked Corneas
Brief Summary	Primary objective of this study was to assess the intrasession, intersession and interobserver variability of the Pentacam-derived posterior corneal elevation measurements in keratoconus eyes and eyes that underwent Corneal Collagen Cross-liknking (CxL) treatment due to progressive keratoconus.
Detailed Description	The Pentacam Classic (Oculus Optikgerate GmbH, Heidelberg, Germany, software version 1.14r04) was used for the sake of the study.Two study groups were formed: 1) Keratoconus group (KC) included patients with progressive keratoconus and 2) Collagen-Cross-linking group (CXL) included keratoconus patients that had been treated with uneventful CXL at least on year prior to their enrollment in the study. Three consecutive scans were obtained by two experienced operators. The same procedure was repeated within two weeks for the assessment of intersession variability. In all cases acceptable maps had at least 10.0mm of corneal coverage.All back elevation points were codified in order to facilitate statistical processing of data. Further to single point analysis, three additional parameters were evaluated: a) zone 4 parameter (z4) which derived by the analysis of all points at the central 4.0mm diameter zone, b) zone 8 parameter (z8) which derived by the analysis of all points at the central 8.0mm diameter zone, and, c) highest elevation point parameter (HEP), which derived by the analysis of the highest elevation points for all participants. Reproducibility of measurements was evaluated by means of intraclass correlation coefficients (ICC). Three different ICC types were calculated: a) intrasession ICC for both operators (ICC1 & ICC2), b) interobserver ICC, and, c) intersession ICC. Moreover, Bland-Altman plots were used to evaluate the level of agreement between the two operators.
Study Type ^ICMJE	Observational
Study Design ^ICMJE	Observational Model: Case Control Time Perspective: Prospective
Target Follow-Up Duration	Not Provided
Biospecimen	Not Provided
Sampling Method	Probability Sample
Study Population	Participants were recruited from the Cornea service of the EIT in a consecutive-if-eligible basis.
Condition ^ICMJE	Keratoconus
Intervention ^ICMJE	Procedure: Corneal Collagen Cross-linking (CXL) The same surgical procedure was applied to all CXLG patients that included: Instillation of proparacaine hydrochloride 0.5% drops for topical anaesthesia, application of a sponge saturated with 10% alcohol to the central cornea for 20-30 seconds and subsequent de-epithelialization by means of a hockey knife. Following de-epithelialization, a mixture of 0.1% riboflavin in 20% Dextran solution was instilled to the cornea for 30 minutes (2 drops every 2 minutes) prior to the irradiation. In details, an 8.0mm diameter of central cornea was irradiated for 30 minutes by UVA light with a wavelength of 370nm and an irradiance of 3mW/cm2.The UVA radiation source that was used is the UV-XTM (IROC AG, Zurich, Switzerland). Instillation of riboflavin drops (1 drop every 2 minutes) was continued during irradiation, as well.
Study Group/Cohort (s)	Keratoconus Group (KG) Keratoconus group (KG) included patients with progressive keratoconus. Collagen-Cross-linking group (CXLG) Collagen-Cross-linking group (CXLG) included keratoconus patients that had been treated with uneventful corneal collagen cross-linking (CXL) at least on year prior to their enrolment in the study. Intervention: Procedure: Corneal Collagen Cross-linking (CXL)
Publications *	Not Provided
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.

Recruitment Information
Recruitment Status ^ICMJE	Completed
Enrollment ^ICMJE	67
Completion Date	November 2011
Primary Completion Date	September 2011 (final data collection date for primary outcome measure)
Eligibility Criteria ^ICMJE	Inclusion Criteria: Progressive keratoconus (Keratoconus group) Corneal collagen cross linking (CxL) treatment at least one year prior to enrollment (CxL group) Exclusion Criteria: Glaucoma Suspicion of glaucoma history of herpetic keratitis corneal scarring severe eye dryness pregnancy or nursing current corneal infection underlying autoimmune disease
Gender	Both
Ages	18 Years and older
Accepts Healthy Volunteers	No
Contacts ^ICMJE	Contact information is only displayed when the study is recruiting subjects
Location Countries ^ICMJE	Greece

Administrative Information
NCT Number ^ICMJE	NCT01471873
Other Study ID Numbers ^ICMJE	25/27-09-2011
Has Data Monitoring Committee	No
Responsible Party	Georgios Labiris, Democritus University of Thrace
Study Sponsor ^ICMJE	Democritus University of Thrace
Collaborators ^ICMJE	Not Provided
Investigators ^ICMJE	Not Provided
Information Provided By	Democritus University of Thrace
Verification Date	November 2011
^ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP

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