Comparison of Posterior Corneal Imaging Before and After LASIK Using Dual Rotating Scheimpflug and Scanning Slit-Beam Corneal Tomography Systems

Abstract

The consistency of DRS measurements suggests that the posterior surface of the cornea does not change appreciably after keratorefractive surgery and is imaged more accurately using DRS compared with SSB. The DRS system affords confidence in interpreting data that are useful for discerning morphologic abnormalities of the cornea, both before and after keratorefractive surgery.

Comparison of dual rotating Scheimpflug–Placido, swept-source optical coherence tomography, and Placido–scanning-slit systems

“…15 It is also essential to identify characteristics and evaluate measurement results from various types of topography before refractive surgery. 2,6,9,11,12 Different results from the same cornea can influence the diagnosis of ocular disease or the measurement of other ocular parameters. 1,13,[16][17][18][19] This prospective cross-sectional study directly examined corneal topography with dual rotating Scheimpflug-Placido (Galilei G2), swept-source OCT (Casia SS-1000), and Placido-scanning-slit (Orbscan IIz) systems.…”

“…6,10,12 Apart from conventional methods using a Placidodisk system, swept-source OCT detects corneal structures using axial images in 16 radial scans within 0.3 second. 10 Comparability of keratometry (K) values between the swept-source OCT system and the conventional Placido-disk system have been on the rise because there is increasing interest in applying new techniques to evaluate the cornea.…”

Demographics of patients having cataract surgery after laser in situ keratomileusis

“…Most recent studies [18][19][20][21][22][23][24][25][26] report the ratio of men having LASIK as 40% to 50%. Although the reasons for this discrepancy remain unclear, one possible explanation is that in the group of eyes with a long AL, including post-LASIK eyes, men tended to have cataract surgery more frequently than women, as shown in the results.…”

Assessment of anterior and posterior corneal indices using two Scheimpflug analyzers

“…In addition, refractive surgery physicians who have access to both systems may be faced with the need to compare serial images of the same patient using 2 different machines. Machine threshold values were first studied on the Orbscan (Bausch and Lomb) (2,(9)(10)(11) and later on the Pentacam (12,13) . With the availability of the Galilei Dual Scheimpflug Analyzer, the primary concern was whether values obtained using the dual Scheimpflug system correlated with those obtained using the single Scheimpflug system and whether images captured by both systems can be safely compared.…”

“…Previous studies have evaluated the agreement between Scheimpflug devices; however, different best-fit sphere (BFS) diameters were used in both devices (1) or only elevation data were compared between the Dual Scheimpflug Analyzer and a Scanning Slit-beam imaging system (2) . Comparisons using different BFS would alter the elevation data obtained by the single Scheimpflug system (compared with the dual Scheimpflug system) because the reference is flatter.…”