View clinical trials related to Astigmatism.
Filter by:The purpose of the study was to identify corneal epithelial- and stromal-thickness distribution patterns in keratoconic eyes using spectral-domain-optical coherence tomography (SD-OCT). Study Hypothesis: SD-OCT provides necessary details about the distribution of corneal epithelial and stromal thicknesses for identification of a pattern characteristic for early keratoconus.
Correlating the accuracy of a refraction done over telemedicine to that of a standard refraction, with a study hypothesis that the results will be equivalent.
The purpose of this clinical trial is to demonstrate that treatments generated by an investigational algorithm reduces spherical aberration compared to currently available iDesign treatments.
Purpose of this study is to compare the astigmatic power of the toric IOL obtained from the AcrySof toric calculator, TECNIS toric calculator, and iTrace toric calculator in a group of patients with preoperative with-the-rule (WTR) and against-the-rule (ATR) corneal astigmatism. The study included 100 eyes with cataract and greater than 0.75 diopter of corneal astigmatism, and the subjects were divided into WTR and ATR group. Keratometric value was measured using autokeratometry, IOLMaster partial coherence interferometry (PCI), iTrace incorporating corneal topography and ray-tracing aberrometry. Based on measured values, toric IOL power calculations were performed using AcrySof, TECNIS and iTrace toric calculators.
The aim of this study is to compare the clinical performance of the Biofinity Toric (comfilcon A) contact lens, versus Air Optix for Astigmatism (lotrafilcon B) over 1 month of daily wear.
The purpose of this study is demonstrate substantial equivalence of an investigational contact lens disinfecting solution to a commercially available contact lens solution in gas permeable lens wearers.
The purpose of this study is demonstrate substantial equivalence of an investigational contact lens disinfecting solution to a commercially available contact lens solution in silicone hydrogel and soft contact lens wearers.
The primary goal of the study is to determine if Optical Coherence Tomography (OCT) measurement of corneal power and astigmatism is more accurate than conventional Placido-ring corneal topography. A second goal is to evaluate OCT-based epithelial thickness mapping. The postoperative epithelial thickness variation will be used to calculate refractive effects and calibrate the smoothing parameter in the mathematical model relating corneal mean curvature and epithelial thickness. A third goal is to assess the repeatability of OCT measurements. A fourth goal is to develop a method of estimating the focusing power, astigmatism, and HOA of the crystalline lens based on measurements of the lens' anterior and posterior capsular topographies and positions with the ultrahigh-speed MIT OCT prototype.
This clinical phase IV study is an open, prospective phase IV study and acts to evaluate the effectiveness of the femtolaser-assisted astigmatic keratotomy.
The purpose of this study is to compare the amount of coma as measured by aberrometry induced by two silicone hydrogel toric lenses in astigmatic participants.