View clinical trials related to Astigmatism.
Filter by:The purpose of this study is to obtain on-eye clinical performance data to evaluate the stability of axis orientation of DDT2 toric contact lenses in the intended population.
the records of astigmatic children were reviewed and any deviation was investigated at near and distance. refractive errors, stereopsis, convergence insufficiency were also evaluated. children were divided into two groups according to the presence of amblyopia and ocular deviations and other parameters were compared between groups.
The aim of this study was to test the hypothesis that OCT-guided 110 µm targeted flaps will result in accurate, predictable, and precise thickness flaps, with low complication rates when performed and compared using both 2D and 3D flap geometry applications and how it correlated to visual experience and quality of life responses during the early postoperative period.
Today, cataract surgery is regarded as refractive surgery, mainly aiming emmetropia, and this makes eliminating corneal astigmatism is critical. Corneal astigmatism of more than 1 diopter has been reported in up to 45% of the cataract surgery candidates. It is possible to reduce pre-existing corneal astigmatism by creating a clear corneal incision at the steep meridian of the cornea, however; creating a small incision can correct the only astigmatism up to 1 Diopter, and sometimes this method may not be easy to perform due to the location of steep meridian like the difficulty while creating a superonasal or inferonasal incision at the left eye. This approach is usually sufficient for correcting astigmatism less than 1 D in most eyes. An opposite side clear corneal incision (OCCI) could enhance the flattening effect on the cornea.
The objective of the study was to compare the handling and performance of Biofinity Toric Multifocal to Ultra Multifocal for Astigmatism.
The magnitude of posterior corneal astigmatism was considered negligible due to the smaller difference in the refractive index between the cornea and the aqueous . though ,neglecting the posterior corneal astigmatism lead to errors during calculation of the toric iols (over or under estimation ) . so we aim to determine the percentage of contribution of posterior corneal astigmatism to total corneal astigmatism in a sample of Egyptian population using scheimpflug imaging (Pentacam ).
MAIN OBJECTIVE: To assess the influence of residual astigmatism on visual acuity in the different lens foci in patients operated on for cataracts with a trifocal intraocular lens implant. SECONDARY OBJECTIVE: To study the influence of residual astigmatism on the visual quality of the patient in the far focus and to determine if there are differences of affectation in the two study groups.
Brief Summary: Age-related cataract is the main cause of impaired vision in the elderly population worldwide. In the UK, more than half of people who are over 65 years old have some cataract development in one or both eyes. The only treatment that can restore functional visual ability is cataract surgery where the opacified crystalline lens is removed by phacoemulsification and an artificial intraocular lens is implanted. It is estimated that around 10 million cataract operations are performed around the world each year. Cataract operations are generally very successful, with a low risk of serious complications. During the past two decades, cataract surgery underwent tremendous change and modernisation resulting in today's small incision phacoemulsification surgery and a safe technique with a short rehabilitation time for the patient. Traditional spherical monofocal intraocular lenses (IOLs) restore best-corrected vision and may lessen the need for spectacles. These IOLs correct only the spherical portion of the total refractive error and do not correct corneal astigmatism. Astigmatism is a visually disabling refractive error affecting the general population, especially those with cataract. At least 15% to 20% of cataract patients have 1.5 diopters (D) or more of corneal or refractive astigmatism. With increased patient expectations, the trend is not only to remove the cataract but also to address the problem of pre-existing astigmatism at the time of surgery. Surgical-induced astigmatism can be reduced by smaller incisions, i.e. microincision cataract surgery (MICS), which by definition is surgery performed through incisions smaller than 2.0 mm, reducing the need for suturing. This results in better corneal optical quality, thus improving visual outcomes. There are also other surgical options to correct preexisting astigmatism during cataract surgery like: selectively positioning of the phacoemulsification incision; astigmatic keratotomy with corneal or limbal relaxing incisions; excimer laser refractive procedures such as photorefractive keratectomy, laser in situ keratomileusis, and laser-assisted subepithelial keratectomy; or implanting pseudophakic toric posterior chamber intraocular lenses (IOLs). Toric IOLs have been shown to result in good visual and refractive outcomes. Combined with MICS, these IOLs can allow effective correction of cylindrical errors intraoperatively, improving visual quality and thus leading to spectacle independence. Plate haptic and loop haptic toric IOLs have been considered for about a decade but have been associated with postoperative rotational instability. Rotation of a toric lens from its intended orientation degrades its corrective power, with approximately 3.3% loss of cylindrical power for every degree off axis. A misorientation of approximately 30° negates the effectiveness of astigmatic correction, and a misorientation of more than 30° may induce additional astigmatism. Although some patients are asymptomatic despite induced astigmatism, others experience symptoms such as blurred or distorted vision, headache, fatigue, eyestrain, squinting, or eye discomfort. Thus, IOL orientation stability is an essential goal in toric IOL design. RATIONALE The purpose of this study is to assess and compare the axial IOL rotation and optical quality (refraction, visual acuity, decentration and tilt) and capsular bag reaction after micro-incision surgery with an IOL implantation in cataract patients - Acrysof SN60WF, Tecnis ZCB00 & Envista MX60 IOL
This is a prospective, multicenter, single-arm, open-label clinical study of the commercially available TECNIS Toric II IOL. The study will be conducted in up to 192 subjects needing unilateral or bilateral cataract surgery in up to 8 sites in United States (US). The subjects will be followed for up to 3-months postoperatively.
The investigational device is an approved femtosecond laser (FSL) device with an integrated imaging system to perform certain steps of the cataract procedure including arcuate incisions (AI) correcting astigmatism, also referred to as arcuate keratotomy (AK). The FSL will perform anterior capsulotomy and lens fragmentation in individuals suffering from age-related cataract with need of cataract surgery and additionally perform arcuate keratotomy in individuals with more than 1.0 Diopter (dpt) of astigmatism. Cataract surgery will be performed in subjects who have signed an informed consent form. Postoperative examinations will be implemented in accordance with the approved Investigational Plan on subjects and includes: postoperative refraction, visual acuity, slitlamp examination, and corneal topography