Active clinical trials for "Astigmatism"

With increasing demands of patients concerning refractive outcome after cataract surgery, toric intraocular lenses (IOLs) that correct corneal astigmatism have been introduced more widely to cataract surgery. Originally toric IOLs were used mainly for patients with high degrees of astigmatism, especially after corneal surgical procedures such as penetrating keratoplasty. Since a couple of years, toric IOLs are available from numerous manufacturers to correct lower amounts of astigmatism which are much more prevalent with about 30% having a corneal astigmatism of 0.75D or more in the cataract population. This should result in less spectacle dependence of patients due to the astigmatic correction. The alternative method to reduce corneal astigmatism as part of cataract surgery is to make incisions on the steeper axis of the cornea such as limbal relaxing incisions or an additional clear corneal incision opposite (OCCI) to the main cataract opening. These techniques are in use since more than 2 decades and are widely used in clinical routine. As with toric IOLs, precise alignment of the cuts with the axis of astigmatism is essential. The disadvantage of the incisional techniques is the variability of the effect between patients since it depends on factors such as the extent of scaring of the cuts after surgery as well as corneal thickness. The main advantage is the simplicity of the technique and the lower cost. Aim of this study is to compare toric IOL implantation and opposite clear corneal incision during cataract surgery to correct corneal astigmatism.

The purpose of this study is to evaluate the safety and effectiveness of the ALLEGRETTO WAVE EYE-Q excimer laser system for the reduction of myopia with or without astigmatism in subjects undergoing photorefractive keratectomy (PRK) treatment.

The purpose of this open, prospective study is to address the effectiveness and precision of the VICTUS™ Femtosecond Laser Platform-assisted astigmatic keratotomy after femtolaser-assisted cataract surgery.

The purpose of the study is to compare the results of LASIK surgery when using Alcon Allegretto wavefront-guided excimer laser system compared to AMO Visx Custom wavefront-guided excimer laser system in patients with nearsightedness with and without astigmatism.

This research project will compare two methods of correcting refractive error (long or short-sightedness) with spectacle lenses. The primary outcome is the proportion of the population requiring spectacle correction who's needs are met through each scheme. Secondary outcomes are the cost effectiveness of these schemes and development of guidelines for identification of those amongst the population suitable for 'ready-made' spectacles. There are two sites involved in this research. Those with uncorrected refractive error will be identified by their distance vision. Those who have impaired vision (at least 20/40) which improves with spectacles will be invited to participate in this research. Participants will be randomly allocated to one of two groups. The first group will receive spectacles with full correction in both eyes and the second group will receive spectacles from a limited inventory. The two schemes will be compared by how many people continue to use the spectacles, vision with the new spectacles, change in the level of visual functioning and quality of life after wearing new spectacles for one month. At the one month visit, if the spectacles provided are not useful, one new pair of custom spectacles will be dispensed.

The objective of this study was to compare the safety and effectiveness of two versions of the Bausch & Lomb Zyoptix Tissue Saving Aspheric Algorithm versus the current Zyoptix Tissue Saving Algorithm when used for myopia and myopic astigmatism LASIK treatment.

The aims of this study are to investigate the effects of ortho-k for astigmatic and myopic reduction and myopic control in children, and the long term effects on corneal curvatures and biomechanics.

The aim of this work is to undertake a range of vision-related measures with soft toric contact lenses soft spherical contact lenses and spectacle lens correction across a range of levels of 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.

The purpose of this study is to collect efficacy and safety data on the WaveLight EX500 excimer laser system for the correction of hyperopia with and without astigmatism by laser in situ keratomileusis (LASIK) treatment.