**5.1 Subclinical keratoconus**

Vertical thickness of Bowman's layer in subclinical keratoconus was decreased inferiorly compared with normal control eyes [51]. Our group demonstrated that Bowman's layer in patients with subclinical keratoconus was significantly thinner centrally and inferiorly, and could be quantified with mean thickness, minimum thickness, Bowman's ectasia index and Bowman's ectasia index-max [69].
