Scleral lens influence on corneal curvature and pachymetry in keratoconus patients.

OBJECTIVES To investigate the influence of full scleral lenses on corneal curvature and pachymetry in keratoconus patients. METHODS In this intervention study, 20 eyes of 14 patients were measured by Scheimpflug imaging (Pentacam HR, Oculus) at two time points: directly and ≥1 week after scleral lens removal. Steep, flat and maximal keratometry (K(steep), K(flat) and K(max)) and optical pachymetry were analyzed. A generalized estimating equation analysis was performed to correct for paired eyes. RESULTS Directly after scleral lens removal, all three curvature parameters were significantly flatter compared to ≥1 week after scleral lens removal. Average K(steep) was 0.7 diopter (D) lower (P<0.001), average K(flat) was 0.5D lower (P=0.037) and average K(max) was 1.1D lower (P<0.001). Directly after scleral lens removal, average optical pachymetry was ±2.5% higher (P<0.001) compared to ≥1 week after scleral lens removal. CONCLUSIONS Although scleral lenses do not mechanically touch the cornea, curvature and pachymetry seem to be influenced by scleral lens wear in keratoconus patients. The duration of these changes remain unclear.