View clinical trials related to Astigmatism.
Filter by:This study aims to assess the rotational stability of the new collameric Nanoflex toric intraocular lens (T-IOL) by STAAR inserted in astigmatic patients after cataract surgery. The purpose of this study is also to determine whether the use of a toric intraocular lens (T-IOL) improves visual acuity.
Bilateral dispensing clinical trial of stenfilcon A against etafilcon A for astigmatism.
This study evaluates the Rayner T-flex Toric IOLs for spherical and astigmatic correction, and rotational stability in cataract surgery. 50 patients with cataract and corneal astigmatism >= 2 diopters will undergo cataract surgery, with implantation of Rayner toric intraocular lens. Post-operative examination will include IOL axis measurements and refraction.
OVERVIEW Cataract is a clouding of the crystalline lens which causes vision loss and blindness if untreated. Cataract surgery is the most frequently performed surgical intervention in medicine with an incidence of 880 surgeries per 100.000 population in 2010 amounting to a total number of over 160.000 surgeries per year in the Netherlands. Approximately 22% of patients with cataract have a substantial pre-existing corneal astigmatism. Toric IOLs provide the opportunity to correct pre-existing astigmatism, offering the patients optimum distance vision without the use of spectacles or contact lenses. Toric IOLs are increasingly used in cataract and refractive surgery. Since the introduction of toric intraocular lenses (IOLs) in the treatment of cataract in patients with pre-existing corneal astigmatism, numerous studies have shown the importance of accurate positioning of the toric IOL to the intended alignment axis. An error of 5º in toric IOL alignment will decrease the anticipated effect by 17% and thus misalignment will decrease the effectiveness of the astigmatism treatment. There are several methods used to align the toric IOL at the intended axis. Most of these use a 3-step ink-marking procedure and are performed manually. Clinical study showed an average error of 5º in toric IOL alignment when using this method. Two new tools that have recently been introduced to the market are the VERION Measurement Module and VERION Digital Marker. Together, these tools provide integrated digital guidance for alignment of toric IOLs and they have the potential to eliminate the error in horizontal axis marking and the alignment axis marking error. This will lead to an improved visual outcome. So far, there are no published studies using the VERION tools for toric IOL alignment in cataract surgery. Therefore, the investigators will perform this randomized control trial. MAIN HYPOTHESIS The investigators hypothesise that cataract surgery with the implantation of a toric IOL, when using the VERION-tools, compared to manual ink-marking, in patients with corneal astigmatism will lead to: - An increase in accuracy in toric IOL alignment OBJECTIVES Primary Objective: The primary objective of the study is to compare the accuracy in toric IOL alignment when using the VERION-tools for alignment of the toric IOL or the conventional manual ink-marking procedure. Other hypotheses and objectives are available in the detailed description.
The purpose of this study was to investigate the overall clinical comfort performance of enfilcon A (test) lens and senofilcon A (control) lens over 15-minutes of lens wear.
Toric intraocular lens (IOL) is now widely used for the cataract surgery with preoperative corneal astigmatism. Symptomatic epiretinal membrane (ERM) is often treated with 25-gauge transconjunctival sutureless vitrectomy, resulting in good visual recovery. So far, however, limited information is available on the the stability of axis rotation, astigmatism correction, and improvement in uncorrected distance visual acuity, using astigmatism-correcting IOL in a 25-gauge transconjunctival sutureless vitrectomy combined with cataract surgery. In the current study, eyes with a preoperative corneal cylinder of more than 0.75 diopter had a triple procedure for idiopathic ERM using a toric IOL. Outcome measures will be the amount of IOL axis rotation, uncorrected visual acuity, corrected distance visual acuity, and corneal and refractive astigmatism up to 6 months postoperatively. We are expecting to show that postoperative IOL axis stability is similar to that reported for cataract surgery alone in vitrectomy (triple procedure) for idiopathic ERM with a toric IOL.
Development of a validated computer-based instrument (software program) for the assessment of intermediate visual acuity.
The aim of this dispensing study is to evaluate the clinical performance of existing wearers of Avaira toric lenses following a refit with Clariti toric over 1 month of daily wear.
The purpose of this study is to evaluate visual distortions reported by pseudophakic patients.
The study hypothesis is that the Biofinity Toric XR lenses will perform as well as or better than the participants' habitual contact lenses.