KeratoconusNCT01471873
Variability of Pentacam-derived Back Elevation Measurements in Keratoconus and Cross-linked Corneas
An observational study of Keratoconus, run by Democritus University of Thrace at 1 site in Greece.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Keratoconus
- What is being tested?
- Corneal Collagen Cross-linking (CXL)
- Type of treatment
- Surgery or procedure
- How many people
- 67 participants
- Where
- 1 siteGreece
- Study dates
- Mar 2011to Nov 2011
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Participants were recruited from the Cornea service of the EIT in a consecutive-if-eligible basis.
Who may be able to join
- Progressive keratoconus (Keratoconus group)
- Corneal collagen cross linking (CxL) treatment at least one year prior to enrollment (CxL group)
Who cannot join
- Glaucoma
- Suspicion of glaucoma
- history of herpetic keratitis
- corneal scarring
- severe eye dryness
- pregnancy or nursing
- current corneal infection
- underlying autoimmune disease
Trial locations and contacts
1 site in 1 country.
About this study
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.
Read the 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.
- Conditions
- Keratoconus
- Being tested
- Corneal Collagen Cross-linking (CXL)
- Keywords
- Posterior corneal surface elevation, Pentacam-Scheimpflung imaging, variability, progressive keratoconus, corneal cross-linking
- Medical subject headings
- Keratoconus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Corneal Collagen Cross-linking (CXL)Procedure or surgery
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 | Role | What they receive |
|---|---|---|
| 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. Receives: Procedure: Corneal Collagen Cross-linking (CXL) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Variability of posterior corneal surface elevation measurements within and between sessions and within and between observers.
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).
Measured: 2 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Nov 2011 (estimated)
- Study startMar 2011
- Primary completionSep 2011
- Study completionNov 2011
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for KeratoconusStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 67 participants (actual)
Sponsor and investigators
- Lead sponsor
- Democritus University of Thrace
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Georgios Labiris, Democritus University of Thrace
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01471873
- Sponsor's protocol ID
- 25/27-09-2011
- Status last verified
- Jan 2017
- First submitted
- 9 Nov 2011
- Last updated
- 18 Jan 2017
- Results posted
- No
- Data monitoring committee
- No
Publications
Labiris G, Giarmoukakis A, Sideroudi H, Bougatsou P, Lazaridis I, Kozobolis VP. Variability in Scheimpflug image-derived posterior elevation measurements in keratoconus and collagen-crosslinked corneas. J Cataract Refract Surg. 2012 Sep;38(9):1616-25. doi: 10.1016/j.jcrs.2012.04.039.
PubMed 22906447
Study at a glance
From the registry record, last updated by the sponsor on 18 Jan 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Variability of Pentacam-derived Back Elevation Measurements in Keratoconus and Cross-linked Corneas
- ClinicalTrials.gov ID
- NCT01471873
- Acronym / sponsor ID
- 25/27-09-2011
- Conditions
- Keratoconus
- Keywords
- Posterior corneal surface elevation, Pentacam-Scheimpflung imaging, variability, progressive keratoconus, corneal cross-linking
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 67 participants (actual)
- Lead sponsor
- Democritus University of ThraceUniversity, hospital or other
- Study start
- Mar 2011
- Primary completion
- Sep 2011 (actual)
- Study completion
- Nov 2011 (actual)
- First posted
- 16 Nov 2011 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Keratoconus Group (KG) | – | –Keratoconus group (KG) included patients with progressive keratoconus. |
| Collagen-Cross-linking group (CXLG) | – | Procedure: Corneal Collagen Cross-linking (CXL)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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Participants were recruited from the Cornea service of the EIT in a consecutive-if-eligible basis.
Key inclusion criteria (2 listed)
- Progressive keratoconus (Keratoconus group)
- Corneal collagen cross linking (CxL) treatment at least one year prior to enrollment (CxL group)
Key exclusion criteria (8 listed)
- Glaucoma
- Suspicion of glaucoma
- history of herpetic keratitis
- corneal scarring
- severe eye dryness
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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. | Procedure or surgery | Collagen-Cross-linking group (CXLG) |
Primary outcome
Variability of posterior corneal surface elevation measurements within and between sessions and within and between observers.
Time frame: 2 weeks
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).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Jan 2017.
- Results publication: PubMed 22906447Labiris G, Giarmoukakis A, Sideroudi H, Bougatsou P, Lazaridis I, Kozobolis VP. Variability in Scheimpflug image-derived posterior elevation measurements in keratoconus and collagen-crosslinked corneas. J Cataract Refract Surg. 2012 Sep;38(9):1616-25. doi: 10.1016/j.jcrs.2012.04.039.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Keratoconus, run by Democritus University of Thrace at 1 site in Greece.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Jan 2017. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Greece. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Variability of posterior corneal surface elevation measurements within and between sessions and within and between observers. (time frame: 2 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT01471873, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Jan 2017.