CHOICE OF SUBJECTIVE OCULAR REFRACTION TECHNIQUE AND CORNEAL TOPOGRAPHY OF KERATOCONUS (RE-CON)

March 19, 2020 updated by: University Hospital, Clermont-Ferrand

Keratoconus is a rare evolving corneal ectasia that alters visual acuity. To improve spectacle-corrected visual acuity, various subjective refraction techniques can be used.

The subjective refraction techniques of keratoconus-carrying patients have never been studied.

The main hypothesis is that the most suitable subjective ocular refraction method varies with the corneal topography of the keratoconus.

The main objective is to define the most appropriate refractive technique(s) based on corneal topographies in order to provide keratoconus-affected patients with the best spectacle-corrected visual acuity.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Keratoconus is a rare evolving corneal ectasia that alters visual acuity. To improve spectacle-corrected visual acuity, various subjective refraction techniques can be used. The Jackson Cylinder Cross Method, the Astigmatic Dial Technique and the Stenopeic Slit are three validated subjective refraction techniques for measuring astigmatism. The subjective refraction techniques of keratoconus-carrying patients have never been studied.

The main hypothesis is that the most suitable subjective ocular refraction method varies with the corneal topography of the keratoconus.

The investigators collect several characteristics of corneal topography of the keratoconus : the average value of the keratometry of the 3 central mm called Km ; the value of the point corresponding to the maximum keratometry (called Kmax), the distance between the center and the point of Kmax, (called d_Kmax) ; the corneal surface variance index called ISV ; the Belin/Ambrósio Enhanced Ectasia Display (called BAD-D).

The main objective is to define the most appropriate refractive technique(s) based on corneal topographies in order to provide keratoconus-affected patients with the best spectacle-corrected visual acuity.

Study Type

Interventional

Enrollment (Actual)

52

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
      • Clermont-Ferrand, France, 63003
        • CHU Clermont Ferrand

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

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • adult persons
  • patients with keratoconus
  • patients with alteration of visual acuity
  • ability to give informed consent to participate in the study
  • affiliation to a social security scheme

Exclusion Criteria:

  • Keratoconus grafted with cornea or with intracorneal rings.
  • Central corneal opacities.
  • Presence of other eye diseases affecting visual acuity.
  • Patients under guardianship, curatorship or justice protection.
  • Pregnant or breastfeeding women.
  • Refusal to participate in the study.

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

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Cohort 1
70 patients are involved and will perform the three conditions.
Behavioral: Cylinder
Patients who receive the Jackson Cross Cylinder Method
Behavioral: Dial
Patients who receive the Astigmatic Dial Technique Method.
Behavioral: Slit
Patients who receive the Stenopeic slit Method.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Measure of keratometry (Km)
Time Frame: day 1
average value of the keratometry of the 3 central mm called Km
day 1
Measure of the maximum keratometry
Time Frame: day 1
value of the point corresponding to the maximum keratometry (called Kmax),
day 1
Measure d_Kmax
Time Frame: day 1
Measure of the distance between the center and the point of Kmax, (called d_Kmax)
day 1
Measure of index of surface varaiance
Time Frame: day 1
measure of the corneal surface variance index called ISV
day 1
Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D)
Time Frame: day 1
Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D)
day 1

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
astigmatism axis
Time Frame: day 1
Collection of the astigmatism axis given by each method, by the autorefractometer and by the corneal topography
day 1
Subsequent modification of the eyeglasses by the optician
Time Frame: day 30
The need (yes / no) for the optician to modify the prescribed spectacle lens (due to poor tolerance)
day 30
possible method
Time Frame: day 1
The impossibility (yes / no) of carrying out each of the 3 refraction methods.
day 1
ametropia value
Time Frame: day 1
The values of the final corrective spheres (myopia or hyperopia).
day 1

Collaborators and Investigators

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

Sponsor

University Hospital, Clermont-Ferrand

Investigators

  • Principal Investigator: Frederic CHIAMBARETTA, University Hospital, Clermont-Ferrand

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

November 18, 2019

Primary Completion (Actual)

March 6, 2020

Study Completion (Actual)

March 6, 2020

Study Registration Dates

First Submitted

November 20, 2019

First Submitted That Met QC Criteria

November 21, 2019

First Posted (Actual)

November 22, 2019

Study Record Updates

Last Update Posted (Actual)

March 20, 2020

Last Update Submitted That Met QC Criteria

March 19, 2020

Last Verified

November 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RBHP 2019 CHIAMBARETTA
  • 2019-A01624-53 (Other Identifier: 2019-A01624-53)

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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