Active clinical trials for "Astigmatism"

The purpose of this prospective multicenter clinical study is to evaluate the visual and refractive outcomes and safety outcomes following bilateral implantation of trifocal and/or trifocal toric 1stQ AddOn (Medicontur) intraocular lenses (IOLs) to correct residual refractive errors, astigmatism, and presbyopia in previously pseudophakic eyes.

Most of the patients presenting for cataract surgery also have pre-existing corneal astigmatism which if left uncorrected can adversely affect visual and refractive outcomes after cataract surgery. Pre-existing astigmatism at the time of cataract surgery can be corrected by either corneal relaxing incisions or implantation of toric IOLs. While the safety and efficacy of these procedures are well established, there are various challenges associated with these techniques that surgeons need to overcome to achieve good outcomes postoperatively. The use of iris registration technology that automatically compensates for cyclotorsion has the potential to improve the alignment accuracy of CRI or toric IOLs. The Cassini Ambient and Catalys Femtosecond Laser incorporate this technology to help cataract surgeons accurately align toric IOLs on the intended axis of implantation or accurately place CRI on the intended meridian. The present study is aimed at evaluating the efficacy of astigmatism correction during femtosecond laser-assisted cataract surgery with Catalys femtosecond laser. The patients will either undergo iris registration guided CRIs or iris registration guided alignment of toric IOLs.

Corneal astigmatism is refractive error that impairs uncorrected visual acuity. When patients undergo cataract surgery, implantation of toric IOL is deemed the most effective choice for correcting corneal astigmatism and reducing postoperative spectacle dependence. The IOL-capsular complex is formed after cataract surgery and intraocular lens (IOL) implantation. Early postoperative mechanical wrapping of the anterior and posterior capsules plays a significant role in preventing IOL decentration and tilt, as well as formation of the IOL-capsular complex which reduces the incidence of posterior cataract opacity. IOL decentration ≥ 0.4 mm or/and IOL tilt ≥7degree were considered clinically significant because of poor post-surgery visual quality especially for optical sophisticated IOLs such as toric IOLs. IOL instability could decrease the curative effect of toric IOL. There are numerous types of toric IOLs; however, AcrySof IQ and TECNIS toric IOL are most frequently used in the Ophthalmology Hospital of Wenzhou Medical University. AcrySof IQ IOL has some differences compared with TECNIS toric IOL. IQ has a modified L haptic design while TECNIS® toric IOL has a modified C haptic design. AcrySof IQ IOL has a discontinuous 360˚ posterior square edge while TECNIS toric IOL has a continuous 360˚ posterior square edge. The AcrySof IQ IOL cylinder power models include 1.00, 1.50, 2.25, 3.00, 3.75, 4.50, 5.25 and 6.00 D. The Tecnis IOL cylinder power models include 1.00, 1.50, 2.25, 3.00 and 4.00 D. Previous study pointed that patients with cataracts with corneal astigmatism achieved comparable improvement in visual acuity, astigmatism correction, CS（sensitive contrast）, rotational stability and satisfaction, following AcrySof and TECNIS toric IOL implantation. However，some other studies found that the Acrysof toric IOL showed significantly greater rotational stability than the Tecnis toric IOL and the rate of surgical IOL repositioning was higher in eyes implanted with TECNIS than with AcrySof toric IOLs for astigmatic correction. Currently, there is no literature guidance to compare the results of cataract surgery combined various types of toric IOLs implantation in patients using CASIA2. The novel anterior segment optical coherence tomography (AS-OCT) device, CASIA2 can accurately evaluate the IOL capsule bending and the lens position after cataract surgery. Also, CASIA2 can be used to documented the dynamic changes of IOL-capsular complex after surgery.

The purpose of this study is long-term follow up of patients with corneal diseases to analyze the quality of surgical interventions and diagnosis. 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. Overall, a long-term follow up is needed to evaluate an early disease progression as well as corneal stability after surgical intervention.

This prospective non-comparative interventional study aims to analyse the pre-operative factors affecting the range of optimal ICL vaulting. the main question is what is the correlation between age, gender, spherical equivalent, white to white, anterior chamber volume and depth and postoperative vault? participants will do preoperative investigations ( specular microscopy, pentacam and biometry ) then refractive surgery (ICL implantation) followed by follow-up visits to assess the post-operative ICL vault and visual outcome.

The objective of the study is to compare the clinical performance of two monthly toric silicone hydrogel contact lenses in habitual wearers, when worn for 1-month each.

Determine if Total30 for Astigmatism contact lenses (CLs) provide a comfortable wearing experience all day. CL discomfort affects most CL wearers with discomfort consistently topping the reasons why established CL wearers drop out of CLs. In fact, studies have consistently found that the frequency of CL dropout is around 20% with this dropout frequency staying relatively stable over the past 20 plus years. This static frequency of CL dropout is surprising since there have been a number of dramatic soft CL innovations during this time frame (e.g., widely available daily disposable CLs, silicone hydrogel CL materials with high oxygen transmissibility, new CL surface coatings).

Cataracts are the major cause of blindness in the world. Cataract surgery, being the most performed surgery in the world today, provide correction by extracting the natural lens from its capsular bag and replaced by an artificial intraocular lens (IOL) implantation. In the UK, almost all patients undergoing cataract surgery by the NHS are given monofocal intraocular lenses (IOLs) which do not correct corneal astigmatic error. It is estimated that around 20% of the population has over 1.50DC of corneal astigmatism. Uncorrected astigmatism not only increase spectacle dependency and reduce quality of life post surgically, but it also adversely affects the overall economic costs. Specialised toric IOLs offer the opportunity to correct pre-existing corneal astigmatism. Previous work has shown a link between reduced vision and balance or mobility. Full correction of refractive error may have greater impact on lifestyle than previously thought.

Subjects will undergo SMILE surgery in one eye and LASIK using Contoura with Phorcides on the contralateral eye to correct myopia.

Cataract surgery by phacoemulsification is the most commonly performed procedure in Pakistan. Cataract surgery aims for visual rehabilitation and freedom from all kinds of eyewear. Pre-operative corneal astigmatism greater than 1.0 Diopter is reported in 42% preoperatively and 58%postoperatively after implanting a monofocal intraocular lens(IOL). Visual acuity tended to worsen postoperatively with increased astigmatism4. Different treatment modalities are used to reduce astigmatism, like toric IOL. Limbal relaxing incision, actuate keratotomy, intrastromal rings, Lasik and femtosecond laser. Most of these modalities are expensive, so they cannot be afforded by the patients as Pakistan is a low-income country with a per capita income of US$1,562 (160th worldwide)