View clinical trials related to Refractive Errors.
Filter by:This study is exploratory and examines whether the refraction results obtained from a novel optical device yields results similar to the ophthalmic refraction measurements obtained from an autorefractor in children.
Primary objective of this study is the development and validation of a web-based application for the examination of the distance visual acuity of normal- and low-vision patients.
The purpose of this multicenter randomized clinical trial is to evaluate the adjunctive effect of repeated low-level red-light therapy (RLRL) and orthokeratology (ortho-k) on myopia control in ortho-k non-responders who have undergone ortho-k treatment but were still experiencing fast myopia progression.
The purpose of this study is to compare the results of vision tests that are algorithmically derived and delivered through a virtual reality headset with those delivered through the existing technology standards (eg. Humphrey for field tests). Tests that the researchers will be conducting include vision field perimetry, Amsler, acuity chart, contrast- sensitivity and currently used office tests.
The two main objectives of this study are to demonstrate safety and effectiveness of implanting the PanOptix Trifocal IOL in patients who have had previous myopic Lasik. The primary objectives to demonstrate clinical safety will be the quality of vision questionnaire (QUVID) which will demonstrate the patient's perception of halos, glares, and starbursts before and after the implantation of the trifocal IOL. The primary objective to demonstrate clinical effectiveness will be done by measuring visual outcomes at distance, intermediate, and near. In addition, the patients will also fill out the spectacle independence questionnaire (IOLSAT Questionnaire) to determine their level of glasses independence postoperatively. In addition, at the conclusion of the study the patient will also fill out a patient satisfaction survey.
This study is exploratory and examines whether the best-corrected visual acuities (BCVA's) from trial frames created with the refraction results obtained from a novel handheld optical device yields results similar to the ophthalmic refraction obtained from an autorefractor in healthy volunteers age stratum of 18 through 65 years.
Conductive keratoplasty (CK) had shown to be a safe and effective procedure for the treatment of low to moderate hypeopia. It had been approved by the U.S. Food and Drug Administration (FDA) to treat presbyope in early 2004. CK appeals to both surgeons and patients as it avoids the need for flap creation, the use of high intraocular pressure (IOP), or tissue ablation. It utilizes "blended vision" rather than the true monovision used with laser in situ keratomileusis (LASIK), which patients tolerate more readily. There is very little reported research about the induction of wavefront aberration by CK. The symptomatology of high order aberrations (HOA) and the way individual Zernike functions were correlated with visual acuity, contrast sensitivity, visual symptoms. This study measured the HOA created by surgically induced myopic shift via CK and LASIK in an effort to better understand the phenomena of regression, multifocality, pseudo-accommodation and monovision.
The purpose of this clinical trial is to evaluate the effectiveness and safety of the multifocal Artiflex Presbyopic intraocular lens.
To compare the prediction error of ORA vs formula for post-LASIK cataract patients when PanOptix IOL was implanted. Using post-operative outcomes to determine if preoperative IOL calculations, including Barrett TK, Barrett Universal II, Hill RBF, ASCRS post-refractive calculator, or intraoperative aberrometry is more accurate when the two methods disagree in patients who have had previous refractive surgery undergo cataract surgery.
To document the refractive status of Chinese schoolchildren and evaluate the association between the degree of refraction and biometric parameters.