NCT04174209

CHOICE OF SUBJECTIVE OCULAR REFRACTION TECHNIQUE AND CORNEAL TOPOGRAPHY OF KERATOCONUS

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 52 (actual)
• Sponsor: University Hospital, Clermont-Ferrand · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

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. 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.

Conditions

• Keratoconus
• Alteration of Visual Acuity

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2019-11-18
• Primary completion: 2020-03-06
• Completion: 2020-03-06
• First posted: 2019-11-22
• Last updated: 2020-03-20

Locations

1 site across 1 country: France