Topographic Paracentral Corneal Thickness With Pentacam and Orbscan: Effect of Acoustic Factor

Abstract

Central and peripheral measurements of the corneal thickness obtained with Orbscan II and Pentacam are significantly different. The removal of the AF in Orbscan II renders lower mean differences but decreases the agreement between both systems and potentially induces an overestimation of CCT and PCT by Orbsan II compared with Pentacam.

Comparison of central and peripheral corneal thickness measurements with scanning-slit, Scheimpflug and Fourier-domain ocular coherence tomography

“…Average central thickness was thicker in this LASIK patient population than in previous studies of ours20–22 and other groups 10–12 14–16 18 23–25. We cannot explain this difference; however, the relatively small sample could be responsible.…”

Repeatability of Pentacam peripheral corneal thickness measurements

“…Error bars represent 95% of confidence interval. or various causes of corneal swelling or thinning (including post-operative oedema, keratoconus, and pellucid marginal degeneration) [1][2][3]6]. Peripheral corneal thickness assessments may be considered as essential in pre-operative evaluation of patients undergoing refractive surgery procedures (LASIK, LASEK) and in corneal ring segment implantation in keratoconus management [18].…”

“…The Pentacam is an easy-to-use biometry system, simple and quick [5] that can be used to obtain the corneal thickness from the central zone of the cornea up to 5 mm away from the centre (close to the limbus). Pentacam has been reported to provide repeatable values of the central and mid-periphery corneal thickness [5][6][7][8][9] with similar values for central thickness as obtained with ultrasound pachymetry in normal eyes [10].…”

“…While there have been many reports on the use of Pentacam to assess the central cornea [3,[5][6][7][8][9][10], less attention has been given to repeatability of Pentacam pachymetry at the near-to-limbus corneal location [19]. The purpose of this study was to assess the repeatability of such peripheral corneal thickness measurements, using Pentacan pachymetry in healthy eyes.…”

“…However, peripheral corneal thickness (PCT) is of interest in many clinical conditions, to identify peripheral pathologic conditions such as keratoconus, pellucid marginal degeneration, and others [6]. Intraocular pressure (IOP) measurement may be differentially affected by CCT and noncentral thickness, especially when non-contact tonometry is used [11].…”