Different optical methods used to measure CCT showed significantly different results compared with US pachometry except for the Pentacam system. Clinicians should take into account the fact that specular microscopy might either underestimate or overestimate values of CCT, whereas Orbscan systematically overestimates CCT compared with US and Pentacam.

Central and peripheral measurements of the corneal thickness obtained with Orbscan II and Pentacam are significantly different. The removal of the AF in Orbscan II renders lower mean differences but decreases the agreement between both systems and potentially induces an overestimation of CCT and PCT by Orbsan II compared with Pentacam.