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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The pattern deviation PD map was defined as the percent deviation from the normal reference map i.
Ectasia or permanent corneal warpage?
From Other Journals Meaning guides attention in real-world scene images: The inferior steepening seen in keratoconus should not be confused with and is not synonymous with corneap protrusion. The ectasia map is the product of fitted Gaussian waveforms for the PD maps of anterior topography and pachymetry.
Overall, in RGP-wearing keratoconus eyes, there warpxge a paradoxical negative shift of the Warpage Index due to cone-apex RGP touch, except in the unusual case where the RGP-corneal contact is not at the cone apex. Using Anterior Ectasia Index of 6. This work is compliant with the Warpafe Insurance Portability and Accountability Act of and adhered to the tenets of the Declaration of Helsinki.
These changes should not be considered ectaticas they are isometricas illustrated in the diagrams below.
Differences in Demarcation Line and Month Outcomes. This system projects 40 optical slits, 20 from the right and 20 from the left, onto the cornea at a degree angle. Normal subjects enrolled in this study were LASIK candidates who had no ocular diseases and have not been wearing contact lenses for at least 2 weeks prior to the exams. The purple area indicates both conditions coexist. On their own, these maps cannot differentiate keratoconus from other corneal pathologies with similar topographic patterns, such as contact lens-related warpage, dry eye disease, and epithelial basement membrane dystrophy.
Subclinical keratoconus detection by pattern analysis of corneal and epithelial thickness maps with optical coherence tomography. Proposed approach for comprehensive corneap and warpage diagnosis in a clinical setting. Longitudinal data analysis using generalized linear models. The study included 22 normal, 31 keratoconic, 11 warpage, and 8 FFK eyes.
Ectasia or permanent corneal warpage? | Defeat Keratoconus
Schematic representation of the change in the corneal profile caused by repeated trauma. LiOptovue, Inc. To differentiate between warpge and contact lens-related corneal warpage by combining focal change patterns in anterior corneal topography, pachymetry, and epithelial thickness maps. Kruskal-Wallis nonparametric tests were used to compare different groups. The change coreal corneal contour may be the result of either mechanical deformation, chronic metabolic insult, or a combination of mechanical and metabolic challenges.
We previously developed diagnostic parameters based on OCT corneal pachymetry and epithelial thickness maps to detect early keratoconus. If so, contact lens cessation will remain necessary for our classification scheme to accurately distinguish between keratoconus and warpage. Global consensus on keratoconus and ectatic diseases. Positive Warpage Index indicates warpage, and negative Warpage Index indicates keratoconus, as shown in Figure 1. The Warpage Index is positive for warpage and negative for keratoconus, except in cases where keratoconus and warpage coexist.
From our clinical evaluation of hundreds of keratoconus patients, the first perceived visual symptoms leading to the diagnosis of early keratoconus occurs after 2 to 3 years of intense and repeated eye rubbing. The main limitation of this study is that the number of cases is relatively small, which can be addressed in a future study with more cases.
However, topography is not sensitive to very early stages of keratoconus when the topographic steepening is masked by focal epithelial thinning. This work is licensed under a Creative Commons Attribution 4. Keratoconus subjects included in this study were diagnosed clinically with the following inclusion criteria: 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.
One of the 19 RGP-corrected keratoconus eyes had mixed keratoconus plus warpage pattern, while in the other 18 the keratoconus pattern predominated.
Hydrogel contact lens-induced corneal warpage.
Invest Ophthalmol Vis Sci. The study included 31 keratoconic eyes 19 of which had recent RGP wear of 20 subjects, 22 normal eyes of 11 subjects, 11 eyes six eyes wearing RGP, five eyes wearing soft toric contact lenses of eight subjects with contact lens-related corneal warpage and eight FFK eyes four of which had recent RGP wear of eight subjects.
Kanellopoulos AJ, Asimellis G. It is calculated by the dot product of the PD maps of anterior topography and epithelial thickness Equation 1. Ectasia or permanent corneal warpage? They can be differentiated by the OCT epithelial map, which shows matching focal thickening in warpage and thinning in keratoconus.
Those with negative Warpage Index values are diagnosed with keratoconus, while those with positive Warpage Index are diagnosed with warpage. Serial topography is useful to monitor the cornea to resolution of the condition. All warpage cases in our study were induced by RGP or soft toric contact lenses instead of regular soft spherical lenses, probably because RGP and soft toric contact lenses had more effect in changing the corneal epithelium.
Received Dec 14; Accepted Jun