“…Recent studies suggest that devices employing Scheimpflug technology, such as the Sirius (Costruzione Strumenti Oftalmici, Florence, Italy), the Galilei (Ziemer Ophthalmic Systems AG, Port, Switzerland), and the Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany), may be used to accurately measure the effective refractive change for surgically treated corneas. The Pentacam HR (Oculus Optikgeräte GmbH) device uses a rotating Scheimpflug camera and presents several methods for calculating corneal power including Gaussian optics and ray tracing (http://www.pentacam.com/sites/calc_corneal_power.php#ptop).…”