View clinical trials related to Astigmatism.
Filter by:The aims of this study are to investigate the effects of ortho-k for astigmatic and myopic reduction and myopic control in children, and the long term effects on corneal curvatures and biomechanics.
This study evaluates the intrastromal correction of ametropia with a femtosecond laser made by 20/10 PERFECT VISION. This laser generates a beam of ultrashort, infrared pulses which enables very precise cuts in the cornea. By these cuts lamellae of the cornea are separated locally, and in the consequence the curvature of the cornea is changed, and the correction of the diagnosed ametropia can be achieved. On the contrary to cuts which are generated with a sharp knife, the cuts generated when using a laser can be generated just inside the cornea without opening the surface of the cornea. This means the procedure is minimal-invasive. The study hypothesis is: Different types of ametropia can be corrected safely and on long-term by intrastromal cuts.
The purpose of this study is to evaluate neutralization of keratometric astigmatism in patients with cataract and astigmatism higher than 1 diopter, with phaco surgery and the implantation of a toric intraocular lens.
A prospective evaluation of postoperative corneal aberrations and visual parameters (e.g. visual acuity) in patients implanted with an AcrySof Toric IOL.
The purpose of this study is to determine if differences in the design of multifocal intra-ocular lenses would mean different values of higher-order aberrations and different performance in objective parameters such as modulation transfer function.
To assess visual performance in patients with low levels (0.5-0.75 Diopters) of corneal astigmatism.
In this study, the investigators employed Visante-OCT (Carl Zeiss, USA), an anterior chamber optical coherence tomography, to monitor the change of anterior chamber dimensions. These data were correlated to anterior and posterior curvature changes collected with the Oculus Pentacam (Oculus Inc., Germany), a corneal topographer based on rotating Scheimpflug principle. To minimize the effect of convergence and excyclotorsion during examination, topical cycloplegic medication was used. The investigators hypothesized that if there is a link between ciliary muscle contraction and cornea curvature, installation of cycloplegic should result in widening of anterior chamber angle to angle distance and flattening of the cornea curvature data.
The purpose of this study is to evaluate the safety and effectiveness of the Akreos Toric IOL following cataract surgery.
The purpose of this study is to compare LASIK outcomes using the WaveLight ALLEGRETTO WAVE™ wavefront guided or optimized excimer laser treatment with the AMO/VISX CustomVue™ and the LADARVision 4000 excimer laser treatment. Standard refractive outcomes such as uncorrected and best corrected visual acuity, and intended vs. achieved postoperative refractions will be evaluated; in addition, high order optical aberrations, contrast sensitivity, and topography will be measured.
To assess which commercially available measurement device is most accurate in measuring low (< 1.0 D) degrees of corneal astigmatism.