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.