Active clinical trials for "Astigmatism"

The purpose of this study is to evaluate the effectiveness and safety of the TFNT20 low cylinder power intraocular lens when implanted in the eye to replace the natural lens following cataract removal.

Multicenter, prospective, single-arm, observational, non-interventional post market clinical investigation (registry study) with the overall objective to assess safety and performance of CLEAR in a real world setting.

The aim is to evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) procedures.

Small amounts of astigmatism are often uncorrected in contact lens wearers. The effect with respect to driving is unknown, but it could threaten safe operation of a motor vehicle, especially under conditions such as nighttime driving when visual abilities are highly challenged. This study measures driving-specific visual abilities and simulated driving performance in participants with astigmatism who either have or do not have their astigmatism corrected. The primary hypothesis is that at a tactical level, contact lenses correcting for astigmatism will result in safer driving performance overall. The secondary hypothesis is that at an operational level, contact lenses correcting for astigmatism will result in better driving-specific visual performance.

To assess the effectiveness of the Verion-LenSx guided arcuate incision technique to reduce astigmatism in a pseudophakic population.

To determine if arcuate incisions performed with the iFS femtosecond laser are safe and effective in reducing corneal astigmatism.

To evaluate the clinical outcomes of Intrastromal Corneal Ring Segment (ICRS) implantation to correct high-degree astigmatism on eyes with prior penetrating keratoplasty (PK).

The investigators' purpose is to study the induced refractive change caused by different 2.8-mm corneal incision locations in phacoemulsification, because the investigators hypothesize that the effect may be different for nasal, temporal, and superior location, although they are considered astigmatism neutral. Patients will be randomized to nasal or temporal incision, or assigned to superior incision, depending on preexisting astigmatism. Visual acuity, refraction, keratometry, Pentacam analysis, intraocular pressure, biomicroscopy, and funduscopy, will be carried out before and after phacoemulsification. Outcome measures will be induced corneal refractive change (Fourier power vector analysis), ISV change, and visual acuity, at 6 months.

The aim of the study is to evaluate if the performance of Invigor A is substantially equivalent to Invigor B contact lenses when used in a one month recommended replacement, daily wear modality.

Irregular astigmatism is one of the most serious and frequent complications of corneal refractive surgery and one of the worst sequelae of other forms of corneal surgery . It is also considered as one of common, serious complications of corneal injuries . Spectacle correction is usually not useful in the correction of corneal irregular astigmatism. Contact lenses represent a good alternative, but their adaptation and stability are limited by the irregular corneal surface and patient discomfort. In recent years, advancements in laser technology have offered better tools for dealing with irregular astigmatism with finding new surgical methods to improve corneal regularity for the correction of irregular astigmatism. Topography-linked excimer laser is a potentially effective technique in the treatment of irregular astigmatism after keratoplasty . In fact, customized ablation was shown to be an effective means of treatment of irregular astigmatism due to different etiologies Such as corneal Injuries , scar , or postoperative. Some of the theoretical advantages of topography-driven photorefractive keratectomy (PRK) are a better astigmatic correction, the possibility of correcting irregular astigmatism, and a smaller ablation volume compared with standard treatments, resulting in better visual performance. Aim of the work To evaluate the efficacy, safety, and predictability of topography-guided photorefractive keratectomy (PRK) to improve refractive status of patient with irregular Cornea.