Corneal Deformation Response in Patients With keratoconus and in Healthy Subjects

Abstract Background To compare the corneal deformation response between patients with keratoconus and healthy subjects and to identify potential characteristics associated with corneal response parameters. Methods This case-control study included a total of 40 keratoconus patients (40 eyes) and 40 age- and sex-matched healthy subjects (40 eyes) whose central corneal thickness (CCT) was less than 500 µm. Pentacam HR and Corvis ST were used to measure the corneal topographies and the corneal deformation response parameters. Results No significant difference was found in the age, sex, laterality distribution, IOP, and CCT between the keratoconus group and healthy controls. The keratoconus eyes had smaller TCT than the healthy controls (p < 0.001), as well as a greater anterior Kmax, posterior Kmax, anterior corneal astigmatism, posterior corneal astigmatism, and posterior maximum elevation (all p < 0.001). The A2l, A2V, and PD were similar between the two groups. The CCR were lower in the keratoconus group, whereas A1L, A1V, and DA were greater in the keratoconus group than in the healthy controls (all P < 0.05). In keratoconus patients, CCR was significantly associated with TCT. A1V was significantly correlated with anterior and posterior corneal astigmatism. Moreover, A2V, CCR, and DA were significantly correlated with posterior maximum elevation. No associations were detected between corneal response parameters and any potential factors in healthy controls. Conclusions Keratoconus eyes showed significant changes in the mechanical properties of the cornea. We hypothesize that local or uneven weakness of the cornea in keratoconus would significantly change all corneal biomechanical properties.