View clinical trials related to Astigmatism.
Filter by:This study seeks to evaluate the clinical performance of a recently released contact lens designed to correct astigmatism to an established contact lens that has historically been used in these patients.
The relative performance of a new toric soft contact lens against toric contact lenses currently available in market, specifically for visual acuity and lens orientation. The study will be conducted in a staged approach (2 stages).
The purpose of this study is to determine the relative performance of a new toric soft contact lens against a toric and a spherical contact lens currently available in market, specifically with regards to the fit and visual acuity as well as the comfort, vision and satisfaction while in the practitioner's office. Approximately 2 hours duration.
The purpose of this study is to determine the relative performance of a new toric soft contact lens against a toric contact lens currently available in market, specifically with regards to the comfort and vision after two weeks of use.
The purpose of this study is to determine the relative performance of a new toric soft contact lens against three toric contact lens currently available in market, specifically with orientation and visual acuity when head is tilted at 90 degrees.
The objective of this study is to quantify differences in nighttime driving performance between the Bausch & Lomb PureVision™ aspheric contact lenses and a conventional spherical contact lens. The primary aims of this study are to determine the differences between B&L PureVision™ aspheric contact lenses and a conventional spherical contact lens in visual performance measures associated with driving, such as number of objects seen. The secondary aims of this study are to determine differences between B&L PureVision™ aspheric contact lenses and a conventional spherical contact lens in driving performance measures such as number of objects hit.
Pterygium is known to induce with-the-rule astigmatism. Excision of pterygium will steepen the cornea and reduce corneal astigmatism. We postulate that the alteration of keratometry reading will indirectly affect the IOL power calculation in cases with concurrent pterygium and cataract. Concurrent pterygium and cataract is common in Hong Kong and other tropical regions. The effect of pterygium excision on intraocular lens power calculation is investigated.
The purpose of this study is to evaluate the visual outcomes and patient satisfaction after implantation of a toric IOL in patients with predicted residual corneal astigmatism between 0.75 and 1.00 D. Cataract is prevalent throughout the world and IOLs are routinely implanted after the extraction of the cataractous lens. It is the most frequently performed surgery in the United States with an estimated 2-3 million procedures performed annually. With the aging population on the rise, as well as the increasing popularity of refractive intraocular lenses, the number of intraocular surgeries continues to rise. Over the years, the surgical technique has evolved from intracapsular extraction to modern phacoemulsification. This development has helped with the evolution of IOLs as well. The IOLs have advanced extensively: different materials and designs are available, permitting implantation through smaller, sutureless incisions. Traditional IOLs are of monofocal design providing vision at one distance, typically far; and correct mainly the spherical component of the refractive error. However, there are patients with corneal astigmatism that require additional surgical treatment such as laser correction (laser in situ leratomileusis, LASIK; photorefractive keratectomy, PRK) or limbal relaxing incisions, RLI). Another alternative is the use of a toric IOL, which has been especially designed to correct both the sphere and the astigmatism. The ACRYSOF Toric IOL is intended for primary implantation in the capsular bag of the eye for visual correction of aphakia and preexisting comeal astigmatism in adult patients with or without presbyopia, who desire improved uncorrected distance vision, reduction of residual refractive cylinder and increased spectacle independence for distance vision. The treatment selection of the corneal astigmatism depends on the amount of cylinder as follows, between 0.25 and 0.75 D creating the surgical incision on the steep axis; between 0.75 and 1.75 D, RLI; between 1 and 2.25 D, toric IOLs; and between 1 and 3.00 D, LASIK/PRK.
To compare the short-term astigmatic outcomes of phacoemulsification cataract surgery and intraocular lens implantation using temporal versus nasal clear corneal incisions.
The aim of the study was to evaluate visual outcomes, contrast sensitivity, glare and induced high order aberrations induced by the new CustomVue software use for wavefront-guided LASIK.