The Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study
- Conditions
- Keratoconus
- Registration Number
- NCT00000155
- Lead Sponsor
- National Eye Institute (NEI)
- Brief Summary
To describe the clinical course of keratoconus and to describe the relationships among its visual and physiological manifestations, including high- and low-contrast visual acuity, corneal curvature, slit lamp biomicroscopic findings, corneal scarring, and quality of life.
To identify risk factors and protective factors that influence the severity and progression of keratoconus.
- Detailed Description
Keratoconus is a bilateral, asymmetric, chronic, progressive ectasia of the cornea characterized by steepening and distortion of the cornea, thinning of the apical cornea, corneal scarring, and treatment-related sequelae, such as abrasions from contact lenses and surgical complications. Patients experience distorted vision that worsens with disease progression. Their vision is typically corrected with spectacles early in the disease and, later, with rigid contact lenses. Some patients eventually undergo corneal transplantation in one or both eyes. Keratoconus affects people in their prime earning years and profoundly affects their lives.
Previous large-scale studies of keratoconus have focused on incidence and prevalence, etiologies, or the clinical management of keratoconus. Few have characterized the course of the disease and risk factors for its progression in large samples of keratoconus patients. The incidence of vision-threatening corneal scarring in keratoconus is unknown. Patient's most frequent questions--how rapidly their keratoconus will progress, how bad their vision will become, whether they will need corneal surgery, how successful their contact lenses will be--cannot be answered on the basis of the current body of knowledge.
The need for a prospective, observational study of keratoconus patients is great. Results from this study will address keratoconus patient's unanswered questions and will enable eye care practitioners to manage this complex ocular disease better.
The Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study is a multicenter, observational study of 1,209 keratoconus patients followed for 3 years.
Patients are examined annually. Study measures include visual acuity, patient-reported quality of life, manifest refraction, keratometry, photodocumentation of the cornea to identify central corneal scarring, photodocumentation of the flattest contact lens that just clears the cornea, slit lamp biomicroscopy, and corneal topography. In rigid contact lens wearers, the fluorescein pattern of the patient's habitual contact lenses is photodocumented.
Patients are examined at 15 clinical centers. The clinical centers enrolled 1,209 patients in 12 months.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- All
- Target Recruitment
- Not specified
Not provided
Not provided
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method
- Secondary Outcome Measures
Name Time Method
Trial Locations
- Locations (14)
Southern California College of Optometry
🇺🇸Fullerton, California, United States
University of Missouri-St. Louis, School of Optometry
🇺🇸St. Louis, Missouri, United States
University Hospitals of Cleveland, Department of Ophthalmology
🇺🇸Cleveland, Ohio, United States
Northeastern Eye Institute
🇺🇸Scranton, Pennsylvania, United States
The Ohio State University, College of Optometry
🇺🇸Columbus, Ohio, United States
Pennsylvania College of Optometry, The Eye Institute
🇺🇸Philadelphia, Pennsylvania, United States
University of Utah, John Moran Eye Center
🇺🇸Salt Lake City, Utah, United States
SUNY State College of Optometry
🇺🇸New York, New York, United States
University of California, Berkeley, School of Optometry
🇺🇸Berkeley, California, United States
Jules Stein Eye Institute, University of California at Los Angeles
🇺🇸Los Angeles, California, United States
University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences
🇺🇸Chicago, Illinois, United States
Nova Southeastern University, Health Professions Division, College of Optometry
🇺🇸Ft. Lauderdale, Florida, United States
Indiana University, School of Optometry
🇺🇸Bloomington, Indiana, United States
Gundersen Lutheran
🇺🇸La Crosse, Wisconsin, United States