Contribution of posterior corneal astigmatism to total corneal astigmatism.

Purpose: To determine the contribution of posterior corneal astigmatism to total corneal astigmatism and the error in estimating total corneal astigmatism from anterior corneal measurements only using a dual-Scheimpflug analyzer.

Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.

Design: Case series.

Optimizing intraocular lens power calculations in eyes with axial lengths above 25.0 mm.

Purpose: To evaluate the accuracy of refractive prediction of 4 intraocular lens (IOL) power calculation formulas in eyes with axial length (AL) greater than 25.0 mm and to propose a method of optimizing AL to improve the accuracy.

Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA, and Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany.

Noninvasive assessment of tear stability with the tear stability analysis system in tear dysfunction patients.

Purpose: To evaluate tear film stability in patients with tear dysfunction and an asymptomatic control group by using the novel, noninvasive Tear Stability Analysis System (TSAS).

Methods: In this prospective case-control study, 45 patients with dysfunctional tear syndrome (DTS) were stratified into three groups (1, 2, and 3/4) based on clinical severity, with higher scores indicating more severe symptoms; 25 asymptomatic control subjects were evaluated. TSAS measurements were performed with the RT-7000 Auto Refractor-Keratometer (Tomey Corporation, Nagoya, Japan).

Comparison of accuracy of intraocular lens calculations using automated keratometry, a Placido-based corneal topographer, and a combined Placido-based and dual Scheimpflug corneal topographer.

Purpose: To compare the accuracy of intraocular lens (IOL) power calculations with automated keratometry, a Placido-based corneal topographer, and a combined Placido-based and dual Scheimpflug corneal topographer.

Methods: Retrospectively, 75 eyes of 62 patients who had phacoemulsification with implantation of the SN60WF IOL were analyzed. Corneal powers were measured using 5 techniques: (1) automated keratometry (AutoK, IOL Master), (2) simulated keratometry from the Placido-based corneal topographer (SimKP, Atlas), (3) simulated keratometry from the combined Placido-based and dual Scheimpflug corneal topographer (SimKP+DS, Galilei), (4) total corneal power of the steep and flat meridians over a central 1.

Repeatability of corneal power and wavefront aberration measurements with a dual-Scheimpflug Placido corneal topographer.

Purpose: To evaluate the repeatability of the Galilei dual-Scheimpflug analyzer in measuring corneal curvature, wavefront aberrations, pachymetry, and anterior chamber depth (ACD).

Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.

Methods: Three consecutive measurements were performed in 1 eye of each subject.

Comparison of corneal powers obtained from 4 different devices.

Purpose: To assess the repeatability and comparability of anterior corneal power values obtained from the Galilei Dual Scheimpflug Analyzer (Ziemer, Port, Switzerland), Humphrey Atlas corneal topographer (Carl Zeiss, Jena, Germany), IOLMaster (Carl Zeiss), and a manual keratometer (Bausch & Lomb Inc, Rochester, New York, USA).

Design: Prospective, comparative study.

Methods: Prospectively, 20 subjects were enrolled.