A Comparison of Two Devices for Measuring the Central Thickness of the Cornea Before and After Surgery (CECOT)

Fondation Ophtalmologique Adolphe de Rothschild50 enrolled

Overview

Corneal topography allows the measure of the radii of curvature and of the thickness of the cornea. It is essential for diagnosis in ophthalmology and allows to highlight corneal irregularities such as a keratoconus, or too thin corneas which are a contra-indication for laser refractive surgery. Several types of corneal topographers are commercially available. Some as the Orbscan(r), operate by analyzing the image of the patterns of a Placido disk associated with a light slit, allowing the collection of thousands of points of the anterior and posterior surface of the cornea. More recent systems such as the Pentacam(r) are based on automatic rotary cameras which capture images of the whole anterior segment of the eye. The aim of this study is to compare two topographs, the Pentacam(r) and the Orbscan(r) and, more specifically, the central corneal pachymetry measurements measured pre- and postoperatively.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Disorders, Refractive

Interventions

Central corneal thickness measurementDEVICE

Medical Language ↔ Plain English

Inclusion Criteria: * Patients for whom a LASIK refractive surgery is planned Exclusion Criteria: * hyperopic patient * another refractive surgery technique * pregnant or lactating woman * patient's opposition to participation in the study, according to the law on research into routine care * patient under a measure of legal protection * absence of affiliation to social security

Outcomes

Primary Outcomes

Concordance of the Orbscan and Pentacam topographs, evaluated by the intra-class correlation coefficient, for the measure of the difference of the central thickness of the cornea before and after surgery.

Time frame: one month