Clinical Ophthalmology (Nov 2020)
Repeatability and Interchangeability of Topometric, Anterior Chamber and Corneal Wavefront Data Between Two Scheimpflug Camera Devices
Abstract
Hesham Mohamed Gharieb,1,2 Hisham Samy Shalaby,3 Ihab Saad Othman4,5 1Faculty of Medicine, Ain Shams University, Cairo, Egypt; 2Research and Development, Eye World Hospital, Giza, Egypt; 3Department of Ophthalmology, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 4Eye World Hospital, Giza, Egypt; 5Faculty of Medicine, Cairo University, Giza, EgyptCorrespondence: Hisham Samy ShalabyDepartment of Ophthalmology, Faculty of Medicine, Ain Shams University, Abbassia Square, Cairo 11591, EgyptTel +20 1003641789Email [email protected]: This study aims to assess the intra-operator repeatability and correlation of the Pentacam HR (device 1) and Sirius (device 2) in measuring anterior segment parameters and to evaluate the agreement of their readings and therefore their interchangeability in a clinical setting.Methods: This is a prospective non-randomized study was conducted on the right eyes of 102 subjects coming to Eye World Hospital, Giza, Egypt. With each machine, four scans were taken by a single examiner. Each device was used to measure keratometric indices, corneal thickness, anterior chamber depth, anterior chamber angle, corneal diameter and corneal optical aberrations.Results: Both devices show high repeatability for corneal thickness, corneal diameter, anterior chamber depth and keratometric indices (except for maximum keratometry, where device 1 shows high repeatability and device 2 shows low repeatability). On the other hand, both devices show poor repeatability for anterior chamber angle, Q-values, root mean square, spherical, coma and trefoil aberrations. The readings of the two devices are strongly correlated as regards only keratometric indices, corneal thickness and anterior chamber depth. In addition, the readings of the devices are in good agreement as regards only keratometric indices (except maximum keratometry), corneal thickness, anterior chamber depth, anterior chamber angle, root mean square, spherical and trefoil aberrations.Conclusion: Both devices showed variable intra-observer repeatability, with the device 1 showing slightly higher repeatability. Despite the similarity between some of the readings of the two devices, caution is advised before considering them interchangeable. We therefore do not recommend using them in alternation in refractive surgery.Keywords: Scheimpflug, wavefront, corneal topography
