Differentiating Keratoconus and Corneal Warpage by Analyzing Focal Change Patterns in Corneal Topography, Pachymetry, and Epithelial. Cont Lens Anterior Eye. Sep;26(3) Hydrogel contact lens-induced corneal warpage. Schornack M(1). Author information: (1)Department of. Before the advent of corneal topography, corneal warpage was generally described as a condition that included distorted keratometer mires.
|Published (Last):||9 June 2010|
|PDF File Size:||18.96 Mb|
|ePub File Size:||19.38 Mb|
|Price:||Free* [*Free Regsitration Required]|
It is calculated by the dot product of the PD maps of anterior topography and epithelial thickness Equation 1. We used the Gaussian waveform, which was cone shaped, to fit the focal ectasia. Evaluation of keratometric, pachymetric, and elevation parameters of keratoconic corneas with pentacam.
Several new tools have been developed to make the detection of FFK more reliable. Keratoconus diagnosis with optical coherence tomography pachymetry mapping. Open darpage a separate window.
Ectasia or permanent corneal warpage?
Subclinical keratoconus detection by pattern analysis of corneal and qarpage thickness maps with optical coherence tomography.
Given that contact lenses are often used for vision correction in keratoconus, an overall diagnostic scheme is needed to account for this overlap. The pachymetry map shows focal thinning in keratoconus, but not in warpage. The change in corneal contour may be the result of either mechanical deformation, chronic metabolic insult, or a combination of mechanical and metabolic challenges. Using just one of the two new indices is not sufficient to distinguish between keratoconus and warpage.
On the contrary, this area of the cornea is located in a more posterior plane than its superior counterpart, as shown on the vertical crossectional image taken by the Scheimplfug camera red arrowand also demonstrated on the elevation map, which reveals a more negative elevation relative to the best fit sphere.
In this study, we developed the two novel indices, Anterior Ectasia Index and Warpage Index, to differentiate keratoconus from warpage by combining the focal changes in anterior corneal topography, pachymetry, and epithelial thickness maps. The Warpage Index was positive in all warpage eyes and negative for all keratoconic and FFK eyes except three wearing rigid gas-permeable contact lens. Longitudinal study of the normal eyes in unilateral keratoconus patients.
The topography maps dorneal repositioned to be centered on the pupil center.
Hydrogel contact lens-induced corneal warpage.
Evaluation of keratometric, pachymetric, and elevation parameters of keratoconic corneas with pentacam. Several new tools have been developed to make the detection of FFK more reliable. Support Center Support Center. Longitudinal study of the normal eyes in unilateral keratoconus patients. Nine of the contact lens-related warpage cases were correctly classified Contact lens warpage was defined as contact lens wearers with topographic abnormality.
Although a negative Warpage Index was consistent with keratoconus, we wanted to incorporate the pachymetry map information to further confirm the classification.
Tripartite classification between normal, warpage, and ectasia requires using both new indices together with the epithelial PSD. As a result, he developed chronic ocular irritation, which in turn prompted him to rub his left eye vigorously with the knuckles of his index finger, often upon awakening. Clinical signs of corneal warpage include changes in refractive error, decreased visual acuity with spectacle correction, and changes in corneal topography.
Keratoconus subjects included in this study were diagnosed clinically with the following inclusion criteria: Kanellopoulos AJ, Asimellis G.
Using Anterior Ectasia Index of 6. This patient sleeps on his left sidewith his head pressed against his hand and forearm. Those with negative Warpage Index values are diagnosed with keratoconus, while those with cornesl Warpage Index are diagnosed with warpage.
This work is compliant with the Health Insurance Portability and Accountability Act of and adhered to the tenets of the Declaration of Helsinki. The elevation map reveals that the elevation is more negative inferiorly.
National Center for Biotechnology InformationU. We previously developed diagnostic parameters based warpsge OCT corneal pachymetry and epithelial thickness maps to detect early keratoconus.
The pulp of the thumb and index finger is softer than the knuckles, and one could predict that if a different technique had been used grinding movements with knucklesthe deformation and thinning would have been more pronounced. Certain individuals who wear hydrogel contact lenses can experience corneal warpage. The minimum epithelial thickness in the keratoconus group was significantly lower than that in the normal group but was not different from that in the warpage or the FFK group.
It is calculated by the dot product of the PD maps of anterior topography and epithelial thickness Equation 1.
We propose the use of a decision tree Fig.