Abstract
Purpose: :
to evaluate a new curvature gradient map to predict post operative corneal remodeling.
Methods: :
: Two groups of post-excimer ablation surgery were retrospectively evaluated; the first group consisted of 32 eyes of 16 myopic subjects and the second consisted of 6 eyes of 4 astigmatic subjects. The new curvature gradient map, implemented on the CSO Corneal Topographer (Florence, Italy), acquired immediately post-operatively was compared to the tangential curvature difference map between 1 and 12 months to determine the relationship. Corneas were divided into 12 regions for analysis: four 90º wide sectors centered on 0º, 90º, 180º, and 270º, with 3 subdivisions in each sector; from a radius of 0-2.75mm (central), from a radius of 2.75-3.25mm (paracentral), and from a radius of 3.25-4.5mm (peripheral). Linear regression analysis was performed by region, comparing the immediate post-op gradient map to the tangential curvature difference between 1 and 12 months.
Results: :
In the myopic group, the following regions a had significant relationship between the initial curvature gradient and the curvature difference between 1 and 12 months: the paracentral zone of the 90º sector (p=0.0145, R2 = 0.1832) and both the central (p= 0.0034, R2 = 0.2522) and paracentral (p= 0.0452, R2 = 0.1271) zones of the 270 º sector. The greatest average initial tangential curvature was present in the 270 º sector. In the astigmatic group, the following regions had a significant relationship: both the central zone (p= 0.0033, R2 = 0.9476) and peripheral zone (p= 0.0003, R2 = 0.9891) of the 0º sector, as well as the peripheral zone of the 90º sector (p= 0.0303, R2 = 0.7786).
Keywords: topography • adaptation: pattern • cornea: epithelium