View clinical trials related to Refractive Errors.
Filter by:A refractive surprise can be defined as the failure to achieve the intended postoperative refractive target or the presentation of unexpected and, unwanted post-operative refractive error. It can cause anisometropia or dominance switch and is a source of patient dissatisfaction due to unmet expectations.The best way to manage refractive surprise is to prevent it. The 2017 NICE guidelines on the management of cataracts provide advice on prevention of refractive surprise through accurate biometry, A-constant optimisation, intraocular lens (IOL) formula selection and avoiding wrong lens implant errors.Benchmark standards for NHS cataract surgery dictate that 85% of eyes should be within 1 dioptre (D) and 55% within 0.5D of target spherical equivalent refraction following surgery.
The goal of this observational study is to test whether surgeries for lenses designed to be implanted in the eye to correct refractive error can be done without the need for using viscoelastic substances that are used routinely nowadays to make it easier to introduce them inside the human eye and protect the inside of the eye during the operation. The main question it aims to answer is that is it safe to do the surgery without using them? to answer this question researchers will access recorded data of patients that underwent refractive surgeries in a private clinic since 2017 and compare them as two groups: those who underwent the traditional procedures and those who had it without the use of dispersive viscoelastics in regard to their vision before and after surgery, their ocular pressure and biomicroscopic analysis of the inside of their corneas before and after surgery.
Purpose: Numerous studies have proven that emmetropization in young animals including humans is regulated by visual input. It has long been hypothesized that peripheral myopic defocus may act as a stop signal to reduce myopia progression and axial elongation. As such, multifocal soft contact lenses (MFCLs) have been utilized for myopia control in school-aged children, with variable efficacies. One potential explanation is that the actual peripheral myopic defocus an eye experiences during MFCL wear may not be identical to the Add power and not sufficient to reduce myopia progression. Our study investigated and compared the peripheral power profiles of myopic eyes when they were uncorrected and wore single vision contact lenses (SVCLs) and MFCLs of different Add powers. Methods: Subjects with -1.00 D to -10.00 D of myopia (SE, determined with manifest refraction) were custom fit with both single vision (SV) and MFCLs (+2.00 and +4.00 D Add; provided by Specialeyes) in both eyes. These Specialeyes MFCLs had an aspheric design with a standard total optical zone of 8.0mm. Cycloplegic central autorefraction was conducted with both Grand Seiko WAM-5500 open-field auto-refractor (Grand Seiko Co Ltd) and OPD OPD-Scan III Wavefront Aberrometer (Marco) on the subjects in the following conditions: (1) no CLs, (2) SVCLs, (3) MFCLs (+2.00D Add), and (4) MFCLs (+4.00D Add). Relative peripheral power profiles were measured using the OPD under the same 4 conditions after cycloplegia. Data in the right eye was used for analysis.
A Study to Evaluate the Safety and Efficacy of the Bausch + Lomb Myopia Control Lens for the Correction of Myopic Ametropia and Slowing the Progression of Myopia in Children
The objective is to compare the refractive parameters of the photorefraction prototype device without cycloplegia with the refractive parameters of reference device, an autorefractometer with and without cycloplegia.
This study aims to determine if Total30 lenses for astigmatism can be successfully fit in participants who are heavy digital device users.
The primary objective of this study is to identify how many focal points and at which distances are necessary for reliable visual curve formation and area of the curve (AoC) calculation using mathematical models and comparing the results to measurements acquired from participants that underwent uncomplicated pseudophakic presbyopia surgery.
This is a unilateral, non-interventional study. Each subject will be unilaterally measured with the WAM-5500 autorefractor by 3 testers. All measurements will be made on the right eye only.
Refractive errors and corneal astigmatism are associated with changes in angle kappa and corneal back elevation at the thinnest point in Pentacam. The purpose of this study is to track: The effect of anterior corneal astigmatism treatment on angle kappa and corneal back elevation.
The purpose of this study is to assess the clinical performance of TOTAL30 for Astigmatism (T30fA) soft contact lenses with Biofinity Toric soft contact lenses.