The Homburg Keratoconus Center (HKC)

The Homburg Keratoconus Center (HKC) - a Keratoconus Observation Study

Aim of this study is to conduct longitudinal and cross-sectional analyses about the corneal ectatic disease Keratoconus based on data obtained from Keratoconus patients in the Homburg Keratoconus Center (HKC).

The Homburg Keratoconus Center (HKC) was founded in 2010 and, up to now, comprises more than 3,000 Keratoconus patients. Topographic, tomographic and biomechanic characteristics of the disease are being analyzed with the intention to elucidate how the disease begins and develops during lifetime.

Study Overview

• Status: Recruiting
• Conditions: Keratoconus
• Intervention / Treatment: Diagnostic test: Topographic, tomographic and biomechanical analysis.

• Study Type: Observational
• Enrollment (Estimated): 5000

Contacts and Locations

Study Locations

• Germany
  • Saarland
    • Homburg, Saarland, Germany, 66421
      • Recruiting
      • Department of Ophthalmology
      • Contact: Berthold Seitz, Prof.Dr.med.; Phone Number: 0049-6841-16-22387; Email: berthold.seitz@uks.eu
      • Contact: Elias Flockerzi, PD Dr.med.; Phone Number: 0049-6841-16-22302; Email: elias.flockerzi@uks.eu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Keratoconus patients of all ages presenting in the department of ophthalmology, Saarland University Medical Center, Homburg, Saarland, Germany, should be included.

Description

Inclusion Criteria:

• All Keratoconus patients presenting in the department of ophthalmology, Saarland University Medical Center, Homburg, Saarland, Germany.

Exclusion Criteria:

• Patients without Keratoconus.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Other

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Patients with Keratoconus; Aim is to include as many Keratoconus patients as possible with the intention to elucidate how the disease begins and develops during lifetime.

Diagnostic test: Topographic, tomographic and biomechanical analysis.; The study is based upon data obtained during routine medical follow-ups using; the Pentacam high resolution (Oculus, Wetzlar, Germany); the Corvis ST (Oculus, Wetzlar, Germany); the Anterior-Segment Optical Coherence Tomograph (AS-OCT) Casia 2 (Tomey, Nagoya, Japan); the Ocular Response Analyzer (Reichert Technologies, New York, USA).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
An overview about development of anterior corneal curvature in Keratoconus disease during lifetime.	The anterior radius of curvature (ARC, 3mm zone) of Keratoconus patients as measured by the Pentacam high resolution (Oculus, Wetzlar, Germany) at different ages (according to: Belin MW and Duncan JK. Keratoconus: The ABCD grading system. Klin Monbl Augenheilkd. 2016; 233(6): 701-707) is put into relation to the age of the Keratoconus patients.	01/01/2011-01/01/2019
An overview about development of posterior corneal curvature in Keratoconus disease during lifetime.	The posterior radius of curvature (PRC, 3mm zone) of Keratoconus patients as measured by the Pentacam high resolution (Oculus, Wetzlar, Germany) at different ages (according to: Belin MW and Duncan JK. Keratoconus: The ABCD grading system. Klin Monbl Augenheilkd. 2016; 233(6): 701-707) is put into relation to the age of the Keratoconus patients.	01/01/2011-01/01/2019
An overview about development of the thinnest corneal pachymetry in Keratoconus disease during lifetime.	The thinnest corneal pachymetry of Keratoconus patients as measured by the Pentacam high resolution (Oculus, Wetzlar, Germany) at different ages (according to: Belin MW and Duncan JK. Keratoconus: The ABCD grading system. Klin Monbl Augenheilkd. 2016; 233(6): 701-707) is put into relation to the age of the Keratoconus patients.	01/01/2011-01/01/2019
An overview about development of the best corrected distance visual acuity in Keratoconus disease during lifetime.	The best corrected distance visual acuity of Keratoconus patients as raised as part of the clinical examination at different ages (according to: Belin MW and Duncan JK. Keratoconus: The ABCD grading system. Klin Monbl Augenheilkd. 2016; 233(6): 701-707) is put into relation to the age of the Keratoconus patients.	01/01/2011-01/01/2019
Reproducibility study: Kmax.	Measurements of Kmax measured by different devices (Pentacam high resolution, Oculus, Wetzlar, Germany; Anterior-Segment Optical Coherence Tomograph (AS-OCT) Casia 2, Tomey, Nagoya, Japan) are being compared and set into relation at different Keratoconus stages with the intention to investigate, whether measurement inaccuracies occur at later Keratoconus stages using different devices.	01/01/2011-01/01/2019
Reproducibility study: Thinnest corneal pachymetry.	Measurements of the thinnest corneal pachymetry as measured by different devices (Pentacam high resolution, Oculus, Wetzlar, Germany; Anterior-Segment Optical Coherence Tomograph (AS-OCT) Casia 2, Tomey, Nagoya, Japan) are being compared and set into relation at different Keratoconus stages with the intention to investigate, whether measurement inaccuracies occur at later Keratoconus stages using different devices.	01/01/2011-01/01/2019
Reproducibility study: Thinnest corneal pachymetry at the apex position.	Measurements of the thinnest corneal pachymetry at the apex position as measured by different devices (Pentacam high resolution, Oculus, Wetzlar, Germany; Anterior-Segment Optical Coherence Tomograph (AS-OCT) Casia 2, Tomey, Nagoya, Japan) are being compared and set into relation at different Keratoconus stages with the intention to investigate, whether measurement inaccuracies occur at later Keratoconus stages using different devices.	01/01/2011-01/01/2019

Collaborators and Investigators

• Sponsor: Universität des Saarlandes

Publications and helpful links

General Publications

• Flockerzi E, Seitz B. Keratectasia severity staging and progression assessment based on the biomechanical E-staging. Eye Vis (Lond). 2024 Jul 1;11(1):24. doi: 10.1186/s40662-024-00392-3.
• Sideroudi H, Flockerzi E, Daas L, Jullien T, Xanthopoulou K, Hamon L, Seitz B. Baseline Characteristics of 1976 Patients With Ectatic Corneal Disorders at a Single Center From 2010 to 2021: A Cross-Sectional Study of the Homburg Keratoconus Center. Eye Contact Lens. 2023 Sep 1;49(9):392-398. doi: 10.1097/ICL.0000000000001014. Epub 2023 Jul 14.
• Flockerzi E, Vinciguerra R, Belin MW, Vinciguerra P, Ambrosio R Jr, Seitz B. Combined biomechanical and tomographic keratoconus staging: Adding a biomechanical parameter to the ABCD keratoconus staging system. Acta Ophthalmol. 2022 Aug;100(5):e1135-e1142. doi: 10.1111/aos.15044. Epub 2021 Oct 16.
• Flockerzi E, Elzer B, Daas L, Xanthopoulou K, Eppig T, Langenbucher A, Seitz B. The Reliability of Successive Scheimpflug Imaging and Anterior Segment Optical Coherence Tomography Measurements Decreases With Increasing Keratoconus Severity. Cornea. 2021 Nov 1;40(11):1433-1439. doi: 10.1097/ICO.0000000000002657.
• Flockerzi E, Vinciguerra R, Belin MW, Vinciguerra P, Ambrosio R Jr, Seitz B. Correlation of the Corvis Biomechanical Factor with tomographic parameters in keratoconus. J Cataract Refract Surg. 2022 Feb 1;48(2):215-221. doi: 10.1097/j.jcrs.0000000000000740.
• Flockerzi E, Hafner L, Xanthopoulou K, Daas L, Munteanu C, Langenbucher A, Seitz B. Reliability analysis of successive Corneal Visualization Scheimpflug Technology measurements in different keratoconus stages. Acta Ophthalmol. 2022 Feb;100(1):e83-e90. doi: 10.1111/aos.14857. Epub 2021 Mar 22.
• Flockerzi E, Xanthopoulou K, Goebels SC, Zemova E, Razafimino S, Hamon L, Jullien T, Kluhspies U, Eppig T, Langenbucher A, Seitz B. Keratoconus staging by decades: a baseline ABCD classification of 1000 patients in the Homburg Keratoconus Center. Br J Ophthalmol. 2021 Aug;105(8):1069-1075. doi: 10.1136/bjophthalmol-2020-316789. Epub 2020 Aug 23.
• Flockerzi E, Xanthopoulou K, Daas L, Feld S, Langenbucher A, Seitz B. Evaluation of Dynamic Corneal Response Parameters and the Biomechanical E-Staging After Accelerated Corneal Cross-Linking in Keratoconus. Asia Pac J Ophthalmol (Phila). 2022 Nov 1;11(6):514-520. doi: 10.1097/APO.0000000000000580.
• Flockerzi E, Berger T, Seitz B, Hamon L, Daas L. Evaluation of dynamic corneal response parameters and the biomechanical E-staging after Intacs(R) SK implantation in keratoconus. Indian J Ophthalmol. 2024 May 1;72(Suppl 3):S495-S500. doi: 10.4103/IJO.IJO_2944_23. Epub 2024 Apr 20.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2011
• Primary Completion (Estimated): January 1, 2036
• Study Completion (Estimated): January 1, 2036

Study Registration Dates

• First Submitted: March 22, 2019
• First Submitted That Met QC Criteria: April 19, 2019
• First Posted (Actual): April 22, 2019

Study Record Updates

• Last Update Posted (Actual): April 27, 2026
• Last Update Submitted That Met QC Criteria: April 22, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Keratoconus; Crosslinking; Intracorneal ring segments; Gas-permeable rigid contact-lenses; Penetrating Keratoplasty; Deep anterior lamellar Keratoplasty; ABCD Grading System
• Additional Relevant MeSH Terms: Eye Diseases; Corneal Diseases; Keratoconus
• Other Study ID Numbers: HKC

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No