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Trial NCT00000155

Resource URI: http://static.linkedct.org/resource/trials/NCT00000155
PropertyValue
linkedct:brief_title The Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study
linkedct:condition <http://static.linkedct.org/resource/condition/6974>
linkedct:criteria Patients with keratoconus were eligible if they were at least 12 years old; had an irregular cornea as determined by keratometry, retinoscopy, or direct ophthalmoscopy in at least one eye; had Vogt's striae, Fleischer's ring, or corneal scarring characteristic of keratoconus in at least one eye; and planned to stay in the area for at least 3 years. They were ineligible if they had bilateral corneal transplants or bilateral nonkeratoconic eye disease (cataract, intraocular lenses, macular disease, or optic nerve disease other than glaucoma).
linkedct: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.
linkedct:download_date Information obtained from ClinicalTrials.gov on December 30, 2009
linkedct:eligibility_gender Both
linkedct:eligibility_healthy_volunteers No
linkedct:eligibility_maximum_age N/A
linkedct:eligibility_minimum_age 12 Years
linkedct:enrollment 0 (xsd:int)
linkedct:firstreceived_date September 23, 1999
linkedct:id NCT00000155
rdfs:label Trial NCT00000155
linkedct:lastchanged_date June 23, 2005
linkedct:lead_sponsor_agency National Eye Institute (NEI)
linkedct:location <http://static.linkedct.org/resource/location/154158>
linkedct:location <http://static.linkedct.org/resource/location/159336>
linkedct:location <http://static.linkedct.org/resource/location/160815>
linkedct:location <http://static.linkedct.org/resource/location/174691>
linkedct:location <http://static.linkedct.org/resource/location/181772>
linkedct:location <http://static.linkedct.org/resource/location/182503>
linkedct:location <http://static.linkedct.org/resource/location/185696>
linkedct:location <http://static.linkedct.org/resource/location/189491>
linkedct:location <http://static.linkedct.org/resource/location/192841>
linkedct:location <http://static.linkedct.org/resource/location/194679>
linkedct:location <http://static.linkedct.org/resource/location/207169>
linkedct:location <http://static.linkedct.org/resource/location/210933>
linkedct:location <http://static.linkedct.org/resource/location/214972>
linkedct:location <http://static.linkedct.org/resource/location/217467>
linkedct:nct_id NCT00000155
linkedct:number_of_arms 0 (xsd:int)
linkedct:number_of_groups 0 (xsd:int)
linkedct:org_study_id NEI-57
linkedct:overall_status Active, not recruiting
linkedct:oversight <http://static.linkedct.org/resource/oversight/2918>
foaf:page <http://clinicaltrials.gov/show/NCT00000155>
linkedct:phase N/A
linkedct:reference <http://static.linkedct.org/resource/reference/50412>
linkedct:reference <http://static.linkedct.org/resource/reference/50578>
linkedct:reference <http://static.linkedct.org/resource/reference/51129>
linkedct:reference <http://static.linkedct.org/resource/reference/51487>
linkedct:source National Eye Institute (NEI)
linkedct:start_date June 1995
linkedct:study_design Natural History, Longitudinal, Prospective Study
linkedct:study_type Observational
linkedct: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.
rdf:type linkedct:trials
linkedct:verification_date November 2001