Comparative study for evaluation of the horizontal white-to-white corneal diameter using the optic low-coherent reflectometer and the Scheimpflug topography in normal Egyptian population

Abstract

Purpose: Comparison of the horizontal white-to-white corneal diameter measured by Lenstar LS 900® (Haag‑Streit AG, Koeniz, Switzerland) and TOMEY TMS-5® (topographic modeling system, version 5) to assess the agreement between them. Setting: El-Agouza police hospital, Egypt. Materials and methods: Comparative prospective cross-sectional clinical study in which measurements of the horizontal WTW corneal diameter were obtained by LENSTAR LS900 and TOMEY TMS-5. Results: The study included 219 eyes of 115 randomly chosen normal Egyptian subjects of both sex (68 males and 47 females). The WTW diameters measured by LENSTAR LS900 and TOMEY TMS-5 ranged from 10.88 to 13.15 mm and 10.69 to 12.94 mm respectively. Lenstar LS 900 gives slightly higher values for WTW diameter than TOMEY TMS-5. Pearson coefficient of correlation (r) revealed a strong statistically significant level of correlation between WTW values measured by both devices (r = 0.87 with p<0.01). Paired samples t-test showed a small mean inter-device difference with high statistical significance (0.29 mm and p<0.01). The Bland-Altman limits of agreement for WTW values measured by them showed a LoA extending from -0.1 to 0.68 mm. Cf the patient.