Not provided
| ID | Type | Description | Link |
|---|---|---|---|
| 2019-A01624-53 | Other Identifier | 2019-A01624-53 |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
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.
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.
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Cohort 1 | Experimental | 70 patients are involved and will perform the three conditions. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Cylinder | Behavioral | Patients who receive the Jackson Cross Cylinder Method |
| |
| Measure | Description | Time Frame |
|---|---|---|
| Measure of keratometry (Km) | average value of the keratometry of the 3 central mm called Km | day 1 |
| Measure of the maximum keratometry | value of the point corresponding to the maximum keratometry (called Kmax), | day 1 |
| Measure d_Kmax | Measure of the distance between the center and the point of Kmax, (called d_Kmax) | day 1 |
| Measure of index of surface varaiance | measure of the corneal surface variance index called ISV | day 1 |
| Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D) | Measure of the Belin/Ambrósio Enhanced Ectasia Display (BAD-D) | day 1 |
| Measure | Description | Time Frame |
|---|---|---|
| astigmatism axis | 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 |
Not provided
Inclusion Criteria:
Exclusion Criteria:
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Name | Affiliation | Role |
|---|---|---|
| Frédéric Chiambaretta | University Hospital, Clermont-Ferrand | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Chu Clermont Ferrand | Clermont-Ferrand | 63003 | France |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 34415365 | Derived | 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. |
Not provided
Not provided
Not provided
| ID | Term |
|---|---|
| D007640 | Keratoconus |
| ID | Term |
|---|---|
| D003316 | Corneal Diseases |
| D005128 | Eye Diseases |
Not provided
Not provided
| ID | Term |
|---|---|
| C031022 | cylindrin |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Dial |
| Behavioral |
Patients who receive the Astigmatic Dial Technique Method. |
|
| Slit | Behavioral | Patients who receive the Stenopeic slit Method. |
|
The need (yes / no) for the optician to modify the prescribed spectacle lens (due to poor tolerance)
| day 30 |
| possible method | The impossibility (yes / no) of carrying out each of the 3 refraction methods. | day 1 |
| ametropia value | The values of the final corrective spheres (myopia or hyperopia). | day 1 |