Active clinical trials for "Astigmatism"

we aimed to analyze the effects of cataract surgery using a 1.8-mm steep-axis clear corneal incision (CCI) on the posterior corneal surfaces based on the keratometry from the rotating Scheimpflug imaging device (Pentacam HR) in candidates for toric intraocular lens (IOL) implantation

The purpose of this study is the investigation of biomechanical properties of the cornea using computer-aided data analysis. Currently, it is known that keratoconus and glaucoma are ocular disease that are associated with biomechanical alterations of the cornea. Corneal ectasia, especially keratoconus, is a corneal disease that leads to an irreversible loss of visual acuity while the cornea becomes steeper, thinner and irregular. For these patients, surgical intervention (e.g. corneal cross-linking) is performed, in case of disease progression. In glaucoma, the information about corneal alterations serves in two ways, first, correct measurement of intra ocular pressure (IOP); second, early diagnosis of suspects before visual field defects are detectable. Especially, the Corvis ST is an air-puff tonometer that measures intraocular pressure, corneal thickness (CCT) as well as dynamic corneal response (DCR) parameters. Most of the DCR parameters are affected by IOP and CCT: Therefore, algorithm are needed to determine parameters without impact of IOP and CCT that are describe the biomechanical properties of the cornea.

The purpose of this study is to evaluate the use of toric high cylinder power intraocular lenses in a larger population in clinical practice and assure the continued safety of these approved devices.

The purpose of this study is to evaluate differences in the comfort at the end of the month between Air Optix® lenses versus Biofinity® lenses in habitual daily wear symptomatic soft contact lens wearers.

Product performance of a Bausch & Lomb Toric Contact Lens compared to Ciba Vision Focus Daily Toric Contact Lens

The aim of this prospective study is to evaluate the clinical performance of habitual wearers of Clariti Toric lenses after a refit with Avaira Vitality Toric lenses for 1-month of daily wear.

Bilateral dispensing study of MyDay Toric, 1-day Acuvue Moist for Astigmatism, and Dailies Aquacomfort Plus Toric lenses

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.

The purpose of this study is to evaluate the lipid uptake, wetting characteristics, and visual performance of AIR OPTIX® AQUA and ACUVUE® OASYS® with HYDRACLEAR® contact lenses when used in conjunction with two contact lens care systems.

To evaluate two toric contact lenses on the ocular physiology of existing contact lens wearers when used in an extended wear modality of days/six nights.