The purpose of this study is to create a database of keratoconic eyes with two or more corneal topographies/tomographies, at least 5 months apart

Title: Keratometry values such as K1, K2 and the angle between these two; Value and location of the thinnest corneal point; Pachymetry progression (radial change of pachymetry); IS value (i.e., ratio of average curvature in superior and inferior sections)

Description:

The primary endpoint is to obtain a database, containing at least two valid corneal biometry measurements (Scheimpflug) recorded at least 5 months apart, for a predetermined number of suitable keratoconus patients.

These data will be used to create a personalized three-dimensional model of the cornea at each time point, which permits classifying corneas according to shape and stage, as well as assessing the influence of patient age, gender, family history and ophthalmic habits (e.g. eye rubbing) on keratoconus progression. Based on corneal changes over time, an estimate of the underlying biomechanical changes will be made. All these data will then be combined to develop software for automated keratoconus detection and progression risk assessment to help ophthalmologists decide when to perform crosslinking on their patients.

The primary variables are the elevation parameters derived directly from the Scheimpflug measuring device export files, along with the demographic and medical information (if available).

Time frame: 5 months

Once a predictive model for keratoconus progression speed based on multiple measurements, this can be improved to make predictions based on a single measurement. Furthermore, the database obtained in this work will also be a valuable resource to analyse the variation in keratoconus shape, which may lead to an improved classification of keratoconus types

Inclusion Criteria:

• Age between 12-40 years.
• Clinically diagnosed mild or moderate keratoconus in one or both eyes
• Two or more Scheimpflug measurements (type Pentacam HR, Pentacam AXL, Ziemer Galilei, CSO Sirius) of good technical quality, separated at least five months apart.

Exclusion Criteria:

• Corneal scarring present in both eyes.
• Known corneal or retinal pathologies, apart from keratoconus
• Known ocular procedures/ treatments (including crosslinking)
• Known systemic diseases (e.g. diabetes, MS, HIV/AIDS, hypertension,…), except allergies
• Change in contact lenses between measurements (e.g. start wearing lenses, change from corneal to scleral lenses, etc.)
• Fluorescein drops instilled into the eye before Scheimpflug measurement.

This study involves a retrospective analysis of data recorded during routine clinical follow-up of keratoconus patients. As such, the impact for the patient is minimal as no additions tests need to be performed