Table 2.

Inclusion and exclusion criteria of the participants in the study.

Inclusion criteria		Exclusion criteria
Healthy	Keratoconus	Healthy	Keratoconus
Age between 18 and 65 years		Presence of any ocular disease or surgery (apart from keratoconus, in this group)
Understanding and signing the informed consent		Use of systemic or ocular drugs that could affect the results
—	With or without intracorneal ring segments	Spherical error higher than ± 15.00 D
—	Stage I, II, or III, according to Amsler–Krumeich classification	Cylindrical error higher than ± 8.00 D