Location of Steepest Corneal Area of Cone in Keratoconus Stratified by Age Using Pentacam

PURPOSE: To evaluate topographic patterns in keratoconic cases and to classify those topographic patterns according to different age groups. METHODS: Four hundred eighty-two eyes of 251 patients with keratoconus were separated into 3 groups based on age. The age range of group 1 (younger) was 21 years (83 eyes), group 2 (middle) was 21 to 40 years (362 eyes), and group 3 (older) was >40 years (37 eyes). All patients underwent full ocular examination and Pentacam (Oculus Optikgerate GmbH) measurement. Topographic patterns were analyzed by comparing the results according-to age groups. RESULTS: Distribution ratios of keratoconic eyes in the three age groups were 17.2% younger, 75.3% middle, and 7.5% older. The most frequent topographic patterns for those patients were vertical bowtie pattern (28.4%) in the younger group, inferior global cone pattern (23.7%) in the middle group, and inferotemporal global cone pattern (16.4%) in the older group. Temporal global cone pattern was more frequently seen among younger keratoconus patients-22% for the eyes in the younger group, 6.9% for the eyes in the middle group, and 11.1% for the eyes in the older group. CONCLUSIONS: In keratoconus, the steepest part of the cone can be located temporally, especially in younger patients, which is unusual. Younger candidates for refractive surgery should be screened for temporal forme fruste. [J Refract Surg. 2009;25:1012-1016.] doi:10.3928/1081597X-20091016-07