Objective and Subjective Diagnostic Parameters in the Fellow Eye of Unilateral Keratoconus

September 15, 2017 updated by: magda torky, Dar Al Shifa Hospital

Literature in Mansoura Ophthalmic Center ,Mansoura University

patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye compared to normal subjects .the patients were examined by schemipflug imaging system (Pentacam)

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This cross-sectional study was carried out on patients presenting keratoconus in one eye and forme fruste keratoconus in the fellow eye; the patients attended the outpatient clinic of Mansoura ophthalmic center between January 2014 and February 2015. This study was approved by the institutional research board of the Mansoura faculty of medicine and was performed in accordance with the ethical standards of the Declaration of Helsinki. All patients included in the study provided informed consent.

Ocular examinations were performed on all eyes included in the study. Clinical Keratoconus was diagnosed if all the following criteria were found:1)asymmetric bow tie with skewed radial axis (SRAX), inferior or central steepening on the topography map, 2)mean keratometry (K)>47diopters or an inferior-superior (I-S) value >1.4diopters according to the Rabinowitz and McDonnell criteria[8],and 3)at least one clinical symptom(i.e., stromal thinning, conical protrusion of corneal apex,Fleischer ring, Vogt striae or anterior stromal scar). Forme fruste keratoconus was diagnosed if all the following criteria were found: 1) normal topography, 2) mean K<47D and I-S ≤1.4,3) normal slit lamp, and 4)keratoconus in the fellow eye.

The eyes with an evident keratoconus diagnosis were included in (Group A)and the fellow eyes were included in (Group B).Control cases(Group C) were selected from the normal database of candidates for refractive surgery with the following:1)normal topography, 2)negative rotating Scheimpflug device indices and negative topographic keratoconus classification, 3)normal slit lamp examination, and 4)no history of eye disease(only one eye of each normal candidate was included in the study depending on a computer-based randomizing program).

The exclusion criteria included previous ocular surgery or trauma, significant corneal scarring or associated ocular pathology.

All eyes were examined by rotating Scheimpflug corneal tomography (Pentacam, Oculus Optikgerate GmbH).No patients in the study wore contact lenses. During the Scheimpflug corneal tomography examination, the patient was properly positioned on the chin rest and forehead strap. The patient was asked to blink several times then open both eyes and stare at a fixed target. After obtaining proper alignment, the automatic release mode started the scan; a total of25 single Scheimpflug images were captured within 2 sec for each eye. Three consecutive scans were taken of each eye by the same examiner. The average of the results of three acceptable measurements was included in the study. Each eye was required to have a corneal map with at least 9 mm of corneal coverage and no extrapolated data.

The Pentacam maps were analyzed. The following anterior and posterior corneal surface parameters were evaluated by the Scheimpflug system: corneal dioptric power at the flattest meridian in the 3 mm-central zone(K1),corneal dioptric power in the steepest meridian in the 3mm-central zone (K2)and mean corneal power in the 3mm-zone (mean K).

The pachymetric map was analyzed, including the central corneal thickness (CCT) at the apex of the geometric center and corneal thickness at the thinnest point (CTmin).The average progression index (PPI avg) was calculated as the progression value at the different rings referenced to the mean curve. The minimum (PPI min) and maximum (PPI max) progression indices were recorded. The Ambrósior elational thickness (ART)was calculated as follows: ARTavg=CTmin/PPIavg,ARTmin = CTmin/PPImin, ARTmax =CTmin/PPImax[9].

The posterior corneal elevation maps were evaluated; a reference best fit sphere was calculated at a fixed optical zone of 8 mm, and the posterior corneal elevation values relative to this reference were recorded. The back difference elevation and multimetric D index values were extrapolated from the difference map of the Belin/Ambrósio-enhanced ectasia display of the Pentacam system.

Contrast and Glare sensitivity test:

The contract and glare tests were carried out with a Mesotest II (Oculus Optikgeräte GmbH, Wetzlar, Germany), which consists of Landolt rings of different contrast levels presented in front of a low-brightness background. There are 4 contrast levels, 1:23, 1:5, 1:2.7, and 1:2, which represent the ratio between the light intensity of the optotypes and the background. There were 8 tests, 4 without glare and 4 with glare. Test 1, with a contrast level of 1:23, is the most easily recognized. For statistical purposes, each level of the contrast or glare test was given a score ranging from 20% at the 1:23 level to 100% at the 1:2 level.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
48

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

10 years to 40 years (Child, Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

unilateral keratoconus

Description

Inclusion Criteria:

  • patients with clinically evident keratoconus in one eye and apparently normal in the fellow eye

Exclusion Criteria:

  • previous ocular surgery or truama,significant corneal scarring or associatedocular pathology

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Control
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
patient
Scheimplug imaging and contrast and sensitivity test
Diagnostic test: Scheimplug imaging and contrast and sensitivity test
examination of the patients using the schemiplug imaging with evaluation of keratometric parametres ,pachymetric parametres ,elevation parameters.
early disease
Scheimplug imaging and contrast and sensitivity test
Diagnostic test: Scheimplug imaging and contrast and sensitivity test
examination of the patients using the schemiplug imaging with evaluation of keratometric parametres ,pachymetric parametres ,elevation parameters.
normal
Scheimplug imaging and contrast and sensitivity test
Diagnostic test: Scheimplug imaging and contrast and sensitivity test
examination of the patients using the schemiplug imaging with evaluation of keratometric parametres ,pachymetric parametres ,elevation parameters.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
keratometric power of the corneal surface
Time Frame: 1 year
in diopter
1 year
corneal thickness(pachymetry)
Time Frame: 1 year
in micrometer
1 year
corneal elevations
Time Frame: 1 year
in micrometer
1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Dar Al Shifa Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 2, 2014

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 5, 2015

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 5, 2015

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 30, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 15, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 19, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 19, 2017

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 15, 2017

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2017

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2352

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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