Fourier Transform of Videokeratography Data: Clinical Usefulness in Moderate and Frome Fruste Keratoconus

Study Overview
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Brief Summary
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Primary objective of this study was evaluate the diagnostic capacity of fourier analysis of keratometric data in differentiating moderate KC and FFK from healthy corneas. Study participants were recruited from the Cornea Outpatient service in a consecutive if eligible basis. Two study groups were formed: a)KC group included patients those were diagnosed and classified for moderate keratoconus according to the Amsler-Krumeich classification system, b) FFK group (FFKG) that included patients diagnosed with FFK, and c) Control group (CG) was formed by refractive surgery candidates. Pentacam (Pentacam HR, Oculus Optikgerate GmbH, Heidelberg, Germany)measurements were performed by the same experienced operator in a consistent way.

Official Title
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Fourier Transform of Videokeratography Data: Clinical Usefulness in Moderate and Frome Fruste Keratoconus

Conditions
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Keratoconus

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: diagnosis of keratoconus KC in the fellow eye according to the Amsler-Krumleich criteria (FFKG) KISA index between 60 and 100% in the FFK eye (FFKG) lack of any KC-related findings / signs in the slit-lamp biomicroscopy (FFKG) uneventful ophthalmologic history (CG) no indications of corneal pathology in slit-lamp biomicroscopy and Placido *disk-based videokeratography (CG) KISA index value less than 60% (CG) diagnosed and classified for moderate keratoconus according to the Amsler-Krumeich classification system (KCG) Exclusion Criteria: for all study groups: previous incisional eye surgery corneal scars and opacities history of herpetic keratitis, severe eye dryness pregnancy or nursing current corneal infection glaucoma suspicion for glaucoma IOP lowering treatment underlying autoimmune disease

Ages Eligible for Study
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Minimum Age: 8 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| KC group<br>KC group included patients those were diagnosed and classified for moderate keratoconus according to the Amsler-Krumeich classification system | |
| Forme Fruste Keratoconus Group (FFKG)<br>Forme Fruste Keratoconus Group (FFKG) included patients diagnosed with FFK. | |
| Control Group (CG)<br>Control group(CG) was formed by refractive surgery candidates. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spherical Component (SphRmin) | Spherical Component (SphRmin) displays the arithmetic mean of all radii of curvature for each ring | One Day | 
| Spherical Eccentricity (SphEcc) | Spherical Eccentricity is the asphericity that is calculated | One Day | 
| Maximum Decentration (MaxDec) | decentration or asymmetry of the astigmatic component which is derived from first order component of fourier analysis | One Day | 
| Regular Astigmatism at the Center(AstC) | the regular astigmatic component is calculated in the center and it is derived from the second order component of Fourier Analysis | One Day | 
| Regular Astigmatism at the Periphery (AstP) | the regular astigmatic component is calculated in the periphery and it is derived from the second order component of Fourier Analysis | One day | 
| Mean Astigmatism (MAst) | Mean Astigmatism is the average of astigmatism at the center and the periphery (MAst) | One Day | 
| Irregularitiy (Irr) |  | one Day | 
| Astigmatism at the Center plus the Irregularities (AstCir) | the irregularities of the cornea which can not be corrected by sphere, cylinder or prism and it is derived from higher order components of Fourier Analysis of Keratometric Data | One day | 
| Total Astigmatism (Tast) which is the sum of Mean Astigmatism and Irregularities. | Total Astigmatism (Tast) is the sum of Mean Astigmatism and Irregularities. | One Day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Keratoconus, Corneal crosslinking, Fourier Analysis of Topographic Data