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.

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Several new tools have been developed to make the detection of FFK more reliable. J Cataract Refract Surg. This figure shows the vertical cross section of a keratoconic cornea, for which two different circles have been used to approximate the superior flatter and inferior steeper hemi-corneal profile.

Several new tools have been developed to make the detection of FFK more reliable.

We used the Gaussian waveform, which was cone shaped, to fit the focal ectasia. Keratoconus What is Keratoconus? Novel pachymetric parameters based on corneal tomography for diagnosing keratoconus. The epithelial PSD was normal 0. Certain individuals who wear hydrogel contact lenses can experience corneal warpage. This limited its ability to detect peripheral corneal abnormalities. The corneal central zone is flattened larger radius of curvature, lower keratometry to compensate for the inferior third of the corneal surface which is concomitantly steepened shorter radius of curvature, higher keratometry.

Hydrogel contact lens-induced corneal warpage.

An abnormally high Anterior Ectasia Index is the result of the coincident focal topographic steepening and pachymetric thinning, which is typical in keratoconus and other ectasia i. However, topography is not sensitive to very early stages of keratoconus when the topographic steepening is masked by focal epithelial thinning.


On the other hand, an abnormal i. Limited oxygen transmissibility through some hydrogel lenses may lead to chronic hypoxia and acidosis. Epithelial pattern standard deviation PSD was calculated and combined with two novel indices, the Warpage Index and the Anterior Ectasia Index, to differentiate between normal, keratoconus, and warpage warpwge.

The FFK cases in the study were the better eyes of asymmetric keratoconus subjects. All warpage cases in our study were induced by RGP or soft toric contact lenses instead of regular soft spherical clrneal, probably because RGP and soft toric contact lenses had more effect in changing the corneal epithelium. TangOptovue, Inc. Evaluation of keratometric, pachymetric, and wrapage parameters of keratoconic corneas with pentacam. Global consensus on keratoconus and ectatic diseases. 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.

Longitudinal data analysis using generalized linear models. The mean curvature a. One of the 19 RGP-corrected keratoconus eyes had mixed keratoconus plus warpage pattern, while in the other 18 the keratoconus pattern predominated. The epithelial PSD was normal 0. The novel Anterior Ectasia Index and Warpage Indices can be used to distinguish between keratoconus and warpage. Using just one of the two new indices is not sufficient to distinguish between keratoconus and warpage.

Using Anterior Ectasia Index of 6. While the alteration of the corneal profile crneal difficult to appreciate in the magnified picture, it is clear that it does not resemble a major protrusion or an ectasia. On the contrary, this is more indicative of warpage of the corneal wallcaused by repeated trauma inflicted by the particular rubbing technique. The warpage cases are then tested with the Anterior Ectasia Index, with the result that the subthreshold cases has pure warpage, while the supra-threshold are diagnosed with both keratoconus and warpage.


This patient admitted to rubbing his eyes frequently with his right hand, massaging vigorously in a horizontal motion. Longitudinal study of the normal eyes in unilateral keratoconus patients.

Ectasia or permanent corneal warpage? | Defeat Keratoconus

Corneal epithelial thickness mapping by Fourier-domain optical coherence tomography in normal warpate keratoconic eyes. The warpage map is the product of the PD maps of anterior topography and epithelial thickness. The values of the three parameters were compared between groups. Tripartite classification between normal, warpage, and ectasia requires using both new indices together with the epithelial PSD. The study included 22 normal, 31 keratoconic, 11 warpage, and 8 FFK warpabe.

It does not correspond to an ectatic protrusion. The pattern deviation PD map was defined as the percent deviation from the normal reference map i. This work is licensed under a Creative Commons Attribution 4.

The ectasia map is the product of fitted Gaussian waveforms for the PD maps of anterior topography and pachymetry. One should not interpret this as an area of local protrusion. Schematic representation of the change in the corneal profile caused by repeated trauma.

There was no difference in age between groups Table 2.

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