Impact of Rigid Gas Permeable Contact Lenses Removal on Anterior and Posterior Corneal Surfaces in Keratoconus Patients

Purpose To evaluate the impact of removal of rigid gas-permeable (RGP) contact lenses on the anterior and posterior cornea surfaces of eyes with keratoconus. Methods Eight eyes of 8 patients with keratoconus (KC) (age 34.3 ± 15.3 years; range 19–60 years) were enrolled. Anterior segment optical coherence tomography (AS-OCT) was performed at 1, 5, 10, 20, and 60 minutes after the patients removed their RGP contact lenses. Measurements included anterior and posterior best-fit sphere (BFS); elevation values and corneal surface areas; corneal thickness at the thinnest point; and the anterior-posterior ratio of the corneal surface (As/Ps) between 1 minute and 60 minutes after RGP contact lens removal. Results Anterior and posterior elevation values and corneal surface areas showed significant increases, whereas anterior and posterior BFS and central corneal thickness decreased significantly (P < 0.01) between 1 minute and 60 minutes after RGP contact lens removal. No statistically significant differences were found in the As/Ps ratio during the first hour after suspending RGP contact lens wear. Conclusions We found that the patients with keratoconus experienced significant changes in both the anterior and posterior corneal shape for 60 minutes after removal of RGP contact lenses.