Active clinical trials for "Astigmatism"

We would like to evaluate the use of a 600μm pre-cut regarding wound architecture and surgically induced astigmatism as compared to a stab-incision (a corneal incision without a pre-cut). A dedicated wound architecture score will be used to evaluate wound configuration. Postoperatively, OCT scans will be obtained, corneal curvature will be measured and subjective and objective refraction will be performed in order to measure the surgically-induced astigmatism.

The purpose of this study is to characterize the safety and effectiveness of the ACRYSOF IQ ReSTOR +2.5 diopter (D) Multifocal Toric Intraocular Lens (IOL) in subjects at least 3 months and no more than 14 months after IOL implantation.

One of the most recent advances in cataract surgery is microincisional phacoemulsification (MICS). Through small incisions of 2.0 mm and less the lens material is emulsified either bimanually or with a thin single coaxial hand-piece. The possible advantages are lower induced corneal astigmatism1, 2, possibly a lower incidence of infection due to higher resistance of the wound to deformation3 and a lower risk of complications such as iris prolapse during surgery in patients at risk such as with intraoperative floppy iris syndrome (IFIS). Additional factors that have to be taken into account are the construction and the position of the incision and the influence of the extraocular force on the wound morphology.4 Another effect that may influence the wound architecture is stromal hydration at the end of surgery.5 Wound architecture has recently been assessed6-9 using optical coherence tomography. Elkady et al.10 observed the wound architecture in MICS cases focusing on corneal thickness and the incision angle. However, none of these studies observed the effect of the wound architecture on post-operative astigmatism. Furthermore, all observations in the past have been performed in the post-operative period only and information concerning the wound architecture intra-operatively is missing. A recently launched CE-marked intra-operative OCT allows observing the wound architecture intra-operatively. One aim of the study is to assess the influence of the intra-operative wound architecture using a similar grading system as used by Calladine and Packard (2007)7 on the resistance to deformation of the wound and the surgically induced astigmatism in MICS and small incision cataract surgery (SICS). In a second part of this exploratory study the effect of a hinged incision with a pre-cut should be assessed along the same line

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.

This study is a prospective, multicenter, bilateral, non-randomized, open-label, clinical study conducted at up to 20 sites in the USA. Subjects were to be bilaterally implanted with one eye having an extended cylinder (high cylinder) toric IOL (model ZCT450, ZCT525 or ZCT600) and the fellow eye having a high cylinder toric IOL (model ZCT450, ZCT525 or ZCT600) or a lower cylinder toric IOL (ZCT300 or ZCT400). This study evaluates the outcomes for subjects implanted with at least one higher cylinder toric IOL.

The purpose of this open controlled multicenter trial is to assess the impact of use of an amniotic membrane on post PKR recovery.

The purpose of this study is to evaluate the efficacy and stability of AT TORBI 709M 4-haptic toric IOL in cataract surgery.

Our study is aimed to observe the long termed effect of contact lens wear on ocular surface, especially focused on visual function and ocular inflammation mediators.

To assess visual performance, refractive outcome, and patient satisfaction with the use of "off the shelf" toric lenses, with a set cylindrical correction of 2.00 or 4.00 diopters, and combined limbal relaxing incisions and/or off-axis intraocular lens rotation, compared to fully targeted toric intraocular lens correction.

This study will compare toric intra-ocular lens (IOL) with limbal relaxing incisions (LRI) in correcting astigmatism in patient undergoing standard cataract surgery. Astigmatism is unequal curvature of the eye; the eye is oval rather than spherical. Uncorrected astigmatism of greater than approximately 0.75 diopters (D) can cause visual blurring, ghosting of images or halos. Over 20% of patients undergoing cataract surgery have astigmatism which is likely to have been corrected by spectacles. Cataract surgery involves the replacement of the natural opacifying crystalline lens with a clear artificial plastic intra-ocular lens (IOL). The lens power can be selected to correct the patient's glasses prescription. The most widely used IOLs only correct glasses at one distance i.e. either near or distance. Residual astigmatism after cataract surgery will need glasses for correction which is undesirable for many patients. Limbal relaxing incisions (LRI) are circumferential partial thickness cuts to the clear window of the eye (cornea) during surgery. These LRIs can correct corneal astigmatism and have no additional risk of complications. Alternatively, toric IOLs are available which correct astigmatism inside the eye. They have been available for routine use in the last few years; technology has markedly improved and the lenses have become cheaper. Studies have suggested toric IOLs provide better vision after cataract surgery than the regular IOLs. Toric IOL are widely used in the private practice and increasingly in the National Health Service (NHS). LRIs are cost effective for treating astigmatism however their predictability is believed to be lower than toric IOLs. As there are no randomised controlled trials comparing the outcomes between LRIs and toric IOLs. This research will address this gap in knowledge and accordingly from this research future practice will be able to provide treatment to patients with information about the best outcomes.