Pentacam Indices Affecting Elevation Difference of Cornea in Patients with Mild and Moderate Keratoconus

Pentacam indices affecting elevation difference of cornea in patients with mild and moderate keratoconus.

A total of 115 eyes were enrolled in different clinical stages. Elevation difference of anterior and posterior of cornea from Belin Ambrosio enhance system achieved. K max, K mean, corneal astigmatism, thinnest corneal thickness, horizontal and vertical distances of thinnest point to apex and asphericity (all measured by pentacam) were correlated with anterior and posterior elevation differences of cornea (measured with Belin/Ambrosio Enhanced Ectesia Display of Pentacam). All measured parameters were classified according to Amsler krumeich classification.

Anterior elevation difference of the cornea had a direct and positive correlation with keratometric maximum (K max) (r = 0.88), mean keratometry (r = 0.83), corneal astigmatism (r = 0.361), and vertical point of thinnest point corneal apex (r= 0.83) and an inverse and positive correlation with with the Thinnest point (r = -0.673) and Asphericity (r= -0.594) (P <0.001) (For all indicators). Correlation between elevation difference posterior with K max (r = 0.849), K mean (r= 0.827), astigmatism (r= 0.26), and vertical point of Thinnest point to corneal apex (r = 0.413) was direct, significant, and positive (P <0.001 for all indices) and correlation between Thinnest point and elevation difference posterior was negative and inverse (r= -0.598; P<0.001). After performing linear step wise regression test, K max (P<0.001), astigmatism (P= 0.005), and K mean (P= 0.007) were the most important Pentacam indices associated with Elevation Anterior, and among the measured Pentacam indices, K mean (P= 0.003), K max (P <0.0001), and astigmatism (P <0.0001) were the strongest indices measured values related to elevation difference posterior, respectively. The best diagnostic points for K max at grade I, grade II, and grade III were 48.4, 51.65, and 74.2, respectively.

K max, K mean, and corneal astigmatism are pentacam indices mostly correlated with anterior and posterior elevation differences of cornea.