KeratoconusRE-CONNCT04174209
CHOICE OF SUBJECTIVE OCULAR REFRACTION TECHNIQUE AND CORNEAL TOPOGRAPHY OF KERATOCONUS
A study testing Cylinder, Dial and Slit in people with Keratoconus and Alteration of Visual Acuity, run by University Hospital, Clermont-Ferrand at 1 site in France.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Keratoconus, Alteration of Visual Acuity
- What is being tested?
- Cylinder, Dial and Slit
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 52 participants
- Where
- 1 siteFrance
- Study dates
- 18 Nov 2019to 6 Mar 2020
- Phase
- Interventional
- 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
Who may be able to join
- 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
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
About this study
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.
Read the 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.
- Conditions
- Keratoconus, Alteration of Visual Acuity
- Being tested
- Cylinder, Dial, Slit
- Keywords
- Keratoconus, Corneal Topography, Eyeglasses, Ocular Refraction, Jackson Cross Cylinder, Astigmatic Dial Technique, Stenopeic slit
- Medical subject headings
- Keratoconus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CylinderBehavioural
Patients who receive the Jackson Cross Cylinder Method
DialBehavioural
Patients who receive the Astigmatic Dial Technique Method.
SlitBehavioural
Patients who receive the Stenopeic slit Method.
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 | Experimental | 70 patients are involved and will perform the three conditions. Receives: Behavioral: Cylinder; Behavioral: Dial; Behavioral: Slit |
What is being measured
The primary outcome is the main question the study is designed to answer.
Measure of keratometry (Km)
average value of the keratometry of the 3 central mm called Km
Measured: day 1
Measure of the maximum keratometry
value of the point corresponding to the maximum keratometry (called Kmax),
Measured: day 1
Measure d_Kmax
Measure of the distance between the center and the point of Kmax, (called d_Kmax)
Measured: day 1
Measure of index of surface varaiance
measure of the corneal surface variance index called ISV
Measured: day 1
Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D)
Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D)
Measured: day 1
Secondary outcomes (4)
astigmatism axis
Collection of the astigmatism axis given by each method, by the autorefractometer and by the corneal topography
Measured: day 1
Subsequent modification of the eyeglasses by the optician
The need (yes / no) for the optician to modify the prescribed spectacle lens (due to poor tolerance)
Measured: day 30
possible method
The impossibility (yes / no) of carrying out each of the 3 refraction methods.
Measured: day 1
ametropia value
The values of the final corrective spheres (myopia or hyperopia).
Measured: day 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Nov 2019
- Study start18 Nov 2019
- Primary completion6 Mar 2020
- Study completion6 Mar 2020
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.
- More trials run by University Hospital, Clermont-FerrandThe sponsor's other registered studies.
- 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 52 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Clermont-Ferrand
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Frédéric Chiambaretta, Principal investigator, University Hospital, Clermont-Ferrand
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04174209
- Sponsor's protocol ID
- RBHP 2019 CHIAMBARETTA
- Other IDs
- 2019-A01624-53
- Acronym
- RE-CON
- Status last verified
- Aug 2026
- First submitted
- 20 Nov 2019
- Last updated
- 7 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Metzger M, Navel V, Barriere JV, Kwiatkowski F, Hebraud J, Mulliez A, Beral L, Chiambaretta F, Dutheil F. Benefits of using corneal topography to choose subjective refraction technique in keratoconus (RE-CON): a prospective comparative crossover clinical study. Graefes Arch Clin Exp Ophthalmol. 2022 Jan;260(1):197-207. doi: 10.1007/s00417-021-05382-y. Epub 2021 Aug 20.
PubMed 34415365
Study at a glance
From the registry record, last updated by the sponsor on 7 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- CHOICE OF SUBJECTIVE OCULAR REFRACTION TECHNIQUE AND CORNEAL TOPOGRAPHY OF KERATOCONUS
- ClinicalTrials.gov ID
- NCT04174209
- Acronym / sponsor ID
- RE-CON / RBHP 2019 CHIAMBARETTA
- Conditions
- Keratoconus, Alteration of Visual Acuity
- Keywords
- Keratoconus, Corneal Topography, Eyeglasses, Ocular Refraction, Jackson Cross Cylinder, Astigmatic Dial Technique, Stenopeic slit
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 52 participants (actual)
- Lead sponsor
- University Hospital, Clermont-FerrandUniversity, hospital or other
- Study start
- 18 Nov 2019 (actual)
- Primary completion
- 6 Mar 2020 (actual)
- Study completion
- 6 Mar 2020 (actual)
- First posted
- 22 Nov 2019 (actual)
- 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.
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.
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 design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 | Experimental | Behavioral: Cylinder, Behavioral: Dial, Behavioral: Slit70 patients are involved and will perform the three conditions. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (6 listed)
- 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.
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 |
|---|---|---|
| CylinderPatients who receive the Jackson Cross Cylinder Method | Behavioural | Cohort 1 |
| DialPatients who receive the Astigmatic Dial Technique Method. | Behavioural | Cohort 1 |
| SlitPatients who receive the Stenopeic slit Method. | Behavioural | Cohort 1 |
Primary outcome
Measure of keratometry (Km)
Time frame: day 1
average value of the keratometry of the 3 central mm called Km
Measure of the maximum keratometry
Time frame: day 1
value of the point corresponding to the maximum keratometry (called Kmax),
Measure d_Kmax
Time frame: day 1
Measure of the distance between the center and the point of Kmax, (called d_Kmax)
Measure of index of surface varaiance
Time frame: day 1
measure of the corneal surface variance index called ISV
Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D)
Time frame: day 1
Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D)
4 secondary outcomes
astigmatism axis
Time frame: day 1
Subsequent modification of the eyeglasses by the optician
Time frame: day 30
possible method
Time frame: day 1
ametropia value
Time frame: day 1
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 7 Aug 2026.
- Results publication: PubMed 34415365Metzger M, Navel V, Barriere JV, Kwiatkowski F, Hebraud J, Mulliez A, Beral L, Chiambaretta F, Dutheil F. Benefits of using corneal topography to choose subjective refraction technique in keratoconus (RE-CON): a prospective comparative crossover clinical study. Graefes Arch Clin Exp Ophthalmol. 2022 Jan;260(1):197-207. doi: 10.1007/s00417-021-05382-y. Epub 2021 Aug 20.
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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.
Frédéric Chiambaretta principal investigator
University Hospital, Clermont-Ferrand
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Cylinder, Dial and Slit in people with Keratoconus and Alteration of Visual Acuity, run by University Hospital, Clermont-Ferrand at 1 site in France.
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 5 inclusion and 6 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 7 Aug 2026. 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 France. 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?
Measure of keratometry (Km) (time frame: day 1). The study lists 5 primary outcomes in all. 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 NCT04174209, 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 7 Aug 2026.