Figure 3.

(a) (blue box) Corneal Thickness Spatial Profile (CTSP)-progressive thickening of the cornea from thinnest point to periphery. (Red box) Percentage Thickness Index (PTI)-percentage of progression of thickness from the thinnest point of the cornea to periphery. (Purple box) Five differential parameters-change in anterior elevation from standard to enhanced reference surface (Df), change in posterior elevation (Db), corneal thickness at thinnest point (Dt), thinnest point displacement (Da), pachymetric progression (Dp). (green box) Pachymetric progression index (PPI)-change in corneal thickness over all 360 degrees of cornea. (b) (Red box) denoting the Indices of Irregularity of Cornea ISV, IVA, KI, CKI, IHA, IHD & Rmin (details in the text)