Baseline findings in the collaborative longitudinal evaluation of keratoconus (CLEK) study

Purpose. To describe the baseline findings in patients enrolled in the Coll aborative Longitudinal Evaluation of Keratoconus (CLEK) Study. METHODS. This is a longitudinal observational study of 1209 patients with k eratoconus enrolled at 16 clinical centers. Its main outcome measures are c orneal scarring, visual acuity, keratometry, and quality of life. RESULTS. The CLEK Study patients had a mean age of 33.29 +/- 10.90 years wi th moderate to severe disease, assessed by a keratometric-based criterion ( 95.4% of patients had steep keratometric readings of at least 45 D) and rel atively good visual acuity (77.9% had best corrected visual acuity of at le ast 20/40 in both eyes). Sixty-five percent of the patients wore rigid gas- permeable contact lens, and most of those (73%) reported that their lenses were comfortable. Only 13.5% of patients reported a family history of kerat oconus. None reported serious systemic diseases that had been previously re ported to be associated with keratoconus. Many (53%) reported a history of atopy. Fifty-three percent had corneal, scarring in one or both eyes. CONCLUSIONS. Baseline findings suggest that keratoconus is not associated w ith increased risk of connective tissue disease and that most patients in t he CLEK Study sample represent mild to moderate keratoconus. Additional fol low-up of at least 3 years will provide new information about the progressi on of keratoconus, identify factors associated with progression, and assess its impact on quality of life.