Aims <p>To evaluate the effects of the Valsalva maneuver on the anterior segment and cornea in keratoconus patients with and without corneal crosslinking.</p> Methods <p>Forty-five eyes of 45 keratoconus patients who underwent corneal cross-linking and 45 eyes of 45 keratoconus patients who did not undergo the procedure were included. Anterior keratometry values (K-flat, K-steep, and K-max), central corneal thickness, corneal apex thickness, thinnest corneal thickness, corneal volume, anterior chamber volume (ACV), anterior chamber depth (ACD), and iridocorneal angle (ICA) values were measured using a&#xa0;Pentacam Scheimpflug camera (Oculus, Germany) before and during the Valsalva maneuver. Changes in the anterior segment parameters from baseline and during the Valsalva maneuver, and the differences in the parameters between the keratoconus groups with and without corneal cross-linking were determined. A p value less than 0.05 was considered statistically significant.</p> Results <p>ACV, ACD, and ICA decreased significantly during the Valsalva maneuver. However, the maneuver had no particular effect on corneal parameters in keratoconus patients (<i>p</i> &gt; 0.05). The changes induced by the Valsalva maneuver were not statistically significant for any parameters in either group of patients with keratoconus.</p> Conclusions <p>The Valsalva maneuver does not lead to significant changes in keratoconus patients with or without corneal cross-linking.</p>