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 Optikgeräte 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.