View clinical trials related to Astigmatism.
Filter by:Aim of the work is to compare the results of femtosecond assisted LASIK and small incision lenticule extraction (SMILE) as regards safety, efficacy and predictability. As a secondary outcomes , the investigators will compare the results of both techniques on corneal biomechanics, dry eye measures, corneal asphericity and higher order aberration.
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.
The purpose of this study is to evaluate the efficacy and stability of AT TORBI 709M 4-haptic toric IOL in cataract surgery.
The principle investigator is evaluating self-reported quality of vision and quality of life in physicians undergoing LASIK, SMILE and PRK surgery.
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.
Development of a validated computer-based instrument (software program) for the assessment of intermediate visual acuity.
This clinical study is an open, controlled, prospective, single center, single-surgeon, post-market-clinical-follow-up study to evaluate the long-term (18 months) effectiveness of the femtolaser-assisted astigmatic keratotomy.
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.
This study is to evaluate the necessity of considering posterior corneal toricity on refractive outcome of patients with cataracts and corneal astigmatism after implantation of intraocular lenses. This is determined by comparing total corneal and refractive astigmatism,and by comparing the expected refractive result with actual refractive astigmatism postoperatively,using total corneal and anterior corneal astigmatism to calculate respectively.
Background: Small Incision Lenticule Extraction or SMILE is a novel form of 'flapless' corneal refractive surgery that was adapted from Refractive Lenticule Extraction (ReLEx). SMILE uses only one femtosecond laser to complete the refractive surgery, potentially reducing surgical time, side effects and cost. If successful, SMILE could potentially replace the current, widely practiced Laser In-situ Keratomileusis or LASIK. The aim of this study is to evaluate whether SMILE is non-inferior to LASIK in terms of refractive outcomes at 3-months post-operatively. Methods/ Design: Single tertiary center, parallel group, single-blinded, paired-eye design, non-inferiority, randomized controlled trial. Participants who are eligible for LASIK will be enrolled for study after informed consent. Each participant will be randomized to receive SMILE and LASIK in each eye. Our primary hypothesis (stated as null) in this non-inferiority trial would be that SMILE differs from LASIK in adults (>21 years old) with myopia (> -3.00D) at a tertiary eye center in terms of refractive predictability at 3 months post-operatively. Our secondary hypothesis (stated as null) in this non-inferiority trial would be that SMILE differs from LASIK in adults (>21 years old) with myopia (> -3.00D) at a tertiary eye center in terms of other refractive outcomes (efficacy, safety, higher-order aberrations) at 3 months post-operatively. Our primary outcome is refractive predictability, which is one of several standard refractive outcomes, defined as the proportion of eyes achieving a postoperative spherical equivalent (SE) within ±0.50 diopter (D) of the intended target. Randomization will be performed using random allocation sequence generated by a computer with no blocks or restrictions, and implemented by concealing the number-coded surgery within sealed envelopes until just before the procedure. In this single-blinded trial, subjects and their caregivers will be blinded to the assigned treatment in each eye. Discussion: This novel trial will provide information on whether SMILE has comparable, if not superior, refractive outcomes compared to the established LASIK for myopia, thus providing evidence for translation into clinical practice.