View clinical trials related to Astigmatism.
Filter by:The purpose of this combined retrospective and prospective chart review analysis is to investigate the safety, efficacy, and predictability obtained via Laser-Assisted In Situ Keratomileusis (LASIK) and Advanced Surface Ablation (ASA) over a wide range of refractive errors The working hypothesis is that there will be no difference in clinical outcomes between patients treated with LASIK or ASA.
Comparison of LASIK outcomes using 3 different lasers and a total of 5 different treatment platforms.
The purpose of this study is to evaluate the safety and effectiveness of the Bausch & Lomb Technolas 217z laser with the investigational Zyoptix Aspheric Algorithm when used for LASIK treatment of myopia and myopic astigmatism.
To evaluate two toric contact lenses on the ocular physiology of existing contact lens wearers when used in an extended wear modality of days/six nights.
The purpose of this study is to determine whether the MEL 80 Excimer Laser is effective in the treatment of mixed astigmatism up to 6.0 D, when used as part of the Laser In Situ Keratomileusis (LASIK) procedure.
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.
This study will evaluate the fitting characteristics and physiological response of two toric lenses manufactured by Vistakon.
The purpose of this study is to determine whether cross-cylinder approach is more effective than routine method in laser correction of astigmatism.
Product performance of a Bausch & Lomb Toric Contact Lens compared to Ciba Vision Focus Daily Toric Contact Lens
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.