Scheimpflug cross-sectioning anterior segment imaging offers significant advantages over traditional placido based curvature analysis and ultrasound pachymetry. The accurate measurement of both the anterior and posterior corneal surfaces and the anterior and posterior lens allows for the creation of a three-dimensional reconstruction of the anterior segment. Changes on both the posterior cornea and/or corneal thickness map are earlier indicators of ectatic change than would otherwise be identifiable with only anterior curvature and ultrasonic pachymetry. Scheimpflug imaging also covers significantly more of the cornea than was possible with placido based devices. This added coverage is critical in the proper diagnosis of peripheral diseases such as pellucid marginal degeneration (PMD).