View clinical trials related to Astigmatism.
Filter by:To assess the effectiveness of the Verion-LenSx guided arcuate incision technique to reduce astigmatism in a pseudophakic population.
Prospective, multicenter, bilaterally-treated, open-label, non-randomized clinical trial.
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.
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.
This study was conducted to evaluate the clinical performance of an investigational silicone-hydrogel lens against Senofilcon A toric lens. The study results were not used for design validation of the investigational product.
To evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx), laser in situ keratomileusis (LASIK) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures.
The aim is to evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures.
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.
Nowadays cataract patient's expectations are closer to those of refractive surgery patients. Patients want to be spectacle independent. However, fifteen to twenty percent of cataract surgery patients have from 1.00 to 3.00 diopters (D) of corneal astigmatism which makes achieving spectacle independence unlikely in this patients unless the astigmatism is treated at the time of cataract surgery. Option to treat this astigmatism include corneal or limbal incisions (LRIs), the use of toric intraocular lenses (IOLs) or LASIK. Regardless of the treatment of choice to correct the astigmatism at time of cataract extraction, a treatment plan has to be calculated preoperatively. This planning include: keratometry measurements and the use of a calculator to estimate the treatment and orientation of IOL and/or placement of the LRIs. New technology has been developed and is widely used. Among this technology, we have the VERION Image Guided System. This system encompasses a reference unit that takes a picture of the eye with the patient in the sitting position creating image of the patient's eye, capturing scleral vessels, limbus and iris features. It measures keratometry as well as the corneal diameter (limbus) and pupil size. The information captured is transferred automatically to its planner where IOL power calculation and astigmatism correction calculation are completed. Additionally, intraoperative wavefront aberrometry has been used in the last couple of years with increase success.
The most common causes for irregular cornea (IC) in hospital contact lens practice are Keratoconus (KC) and related cornea thinning disorders. These conditions cause mild to marked impairment of vision and cannot be effectively corrected by spectacles and soft contact lenses. The gold standard in the management of KC is Corneal Rigid Gas Permeable contact lenses (corneal lenses), which correct approximately 90% of the corneal irregularity. Compared with a normal cornea, the cornea in KC is irregular and this results in a compromise to the fit of rigid corneal lenses. Specifically, they bear on the cornea and this, together with the vulnerability of the cornea in KC, are implicated in corneal scarring, and disease progression as well as a significantly reduced vision related quality of life (QoL) in KC compared with corneal lens wearers who have no KC. In cases where the compromise fit of corneal lenses proves problematic, large diameter Scleral RGP contact lenses (scleral lenses) may be used as a problem solver. Unlike the smaller corneal lenses which bear on the cornea, the scleral lenses completely bridge over the cornea and bear on the sclera. The aim of this research is to investigate the performance of scleral lenses in KC participants who habitually wear corneal lenses. The research question: is there a measurable difference in the visual performance and visual quality of life in participants with Irregular cornea disorders like keratoconus and other related conditions, who habitually wear corneal lenses in comparison with scleral lenses.