Longitudinal assessment of the progression of severe keratoconus based on corneal topography.

We aimed to assess long-term disease progression in patients with severe keratoconus (KC). Clinical records of 125 patients (201 eyes) with severe KC followed-up for > 12 months were retrospectively analyzed. From these, 28 patients (31 eyes) were included. Corneal topography parameters evaluated included thinnest corneal thickness (TCT), maximum keratometry (Kmax), anterior and posterior mean corneal radii of 3 mm (aKM, pKM), steep keratometry, and KC screening indices. All patients wore rigid gas permeable contact lenses (RGPCLs) for an extended period. The median patient age and follow-up period were 20 (interquartile range [IQR] 17-22) years and 25 (15-38) months, respectively. Compared to baseline, the aKM, Kmax, and KC screening indices on the anterior corneal surface were reduced at the final follow-up (P < 0.05). No changes were observed in RGP-corrected visual acuity, TCT, pKM, or KC screening indices on the posterior corneal surface. The higher the baseline value, the greater the reduction in aKM and Kmax. Five patients (16%) experienced disease progression during follow-up. Patients with severe KC showed reduced anterior corneal surface curvature and no change in corneal thickness during an average follow-up period of 2-3 years while wearing RGPCLs.