[Development of a new topographic index of corneal regularity].

PURPOSE: To develop a new topographic index that quantifies corneal surface micro irregularities. METHODS: One hundred and fifty five eyes from 128 patients, with a mean age of 29,2 years were evaluated by corneal topography and divided into three groups. One group was composed of 50 eyes from patients with regular corneas, a second group included 45 eyes with corneal macro irregularities, and a third group included 60 eyes with corneal micro irregularities. With the values of the radii of curvature obtained in the numeric map of the corneal topography, we calculated an algorithm that could quantify differences in dioptric power between points that were very near each other. We used descriptive statistics to analyze each group, and Scheffé multiple comparison of means to compare between the different groups. RESULTS: The mean irregularity index was in group I below 1, in group II between 3 and 4, and in group III eyes with corneal micro irregularities higher than 7. CONCLUSIONS: The new index that we have developed is able to quantify corneal micro irregularities of the corneal surface and its value increases in the presence of corneal micro irregularities.