View clinical trials related to Refractive Error.
Filter by: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.
This study will be a 2-phase, prospective, multicenter, open-label, non-comparative, non-randomized clinical investigation to confirm the safety and effectiveness of the ELITA system.
Phase 3 study to evaluate the safety and effectiveness of LNZ101 for the treatment of Presbyopia.
Prospective, multi-center, non-interventional, randomized, comparative clinical study to identify an optimal refractive technique that provides maximum plus refractive endpoint for best corrected distance visual acuity (BCDVA).
Retrospective collection of data from medical records, multicenter, post-market clinical follow-up study.
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.
This is a multicenter, prospective, randomized, subject- and evaluator-masked, bilateral-implant study conducted at up to 15 sites worldwide. A total of up to 280 subjects will be randomized in a 1:1 ratio for implantation with either the TECNIS Symfony plus IOL Model ZHR00V or the Trifocal IOL. This will ensure that data from at least 100 subjects in the TECNIS Symfony plus lens group and at least 100 subjects in the Trifocal lens group will be available for analysis at the 6-month follow-up timepoint. All subjects will be followed for up to 6 months postoperative.
This study will be a 12-month, prospective, multicenter, open-label, non-comparative, non-randomized clinical investigation conducted at 8 to 14 sites. A total of 383 subjects will be enrolled to achieve approximately 268 treated subjects, resulting in at least 241 evaluable subjects at the point of refractive stability. After signing the informed consent, subjects meeting all inclusion and exclusion criteria in both eyes may be scheduled for surgery. The follow-up visit schedule will be the same for each operative eye.
Some programs do the screening, refraction testing and provision of spectacles to children entirely in the school setting ("School Model"). One strength of such programs is that most children at school who need spectacles get them. However, sustainability is poor, because spectacles cannot be sold in many schools and there may be too few refractionists to cover all schools in most countries. Other programs provide vision screening at schools but refer children who fail vision screening to nearby facilities for refraction and distribution/sale of spectacles ("Referral Model"). This model's strengths include a lower demand for refractionists and opportunities for the spectacles to be sold. However, a disadvantage is that most of the referred children do not attend the specialist facility. One way to improve this might be to enhance the Referral Model and a recent USAID review by Priya Reddy and Ken Bassett showed that involving teachers in vision screening and family counseling significantly increases children's use of spectacles. Therefore, at 141 schools in India, involving over 42,300 children (assuming a minimum of 300 children/school), the investigators will study an "Improved Referral Model," with strong teacher involvement, to investigate the potential benefits of combining the lower costs of the "Referral Models" with the high uptake of the "School Model". The investigators will also assess the effects of allowing parents to purchase enhanced spectacles, rather than having their child use free spectacles. Children will be randomized by the school to the "School Model," "(Improved) Referral Model" or the "(Improved) Referral Model + Cost Recovery (sale of "upgrade spectacles" alongside offering free spectacles. The main study outcome will be program cost-effectiveness, defined as the program cost per child identified with correctable refractive error, who receives spectacles, and wears them at an un-announced visit between 8 to 12 weeks after distribution. Profit on spectacles sold in the "Referral + Cost Recovery" group will be subtracted from the program costs in this study group. The groups will be compared, with and without adjustment for baseline characteristics.
The purpose of this study was to evaluate visual acuity at distance when wearing DDT2 contact lenses compared to Clariti contact lenses.