Active clinical trials for "Myopia"

Clinical evaluation of stenfilcon A compared with narafilcon A and delefilcon A This is a total 120 subject, randomized, open label, bilateral wear, two week crossover study (each lens for 1 week) evaluating the clinical performance of stenfilcon A spherical lenses compared to narafilcon A or delefilcon A spherical lenses.

The purpose of this study is to determine whether improved outdoor time has an effect on the onset and progression of myopia in children.

The photorefractive keratectomy was the first correction mode refractive laser. It's a photo-ablation of a predetermined thickness of anterior corneal stroma. Debridement of epithelium can be done either mechanically (m-PRK) or by laser (trans-PRK). Trans-PRK has a lot of interests: facility and speed of procedure as well as suppression of human variable. Very good results are obtained by m-PRK. The aim of this study is to show equivalence or non inferiority of trans-PRK over conventional m-PRK in terms of safety and refractive efficiency

The purpose of this study is to evaluate the effect of +3.00ADD vs single vision spectacle on the progression of myopia in children. Many studies applying bifocals or multifocal spectacles to intervene the progression have been carried out based on the idea that myopia was caused by excessive accommodation, however, the effect was limited. The possible reason is that bifocal or multifocal spectacles still not fully adjust the accommodative error in myopia children.

A prospective study included 20 patients with super high myopia who underwent bilateral uneventful cataract. 360°anterior capsule polishing was performed with double-ended capsule polisher randomly in one eye, and the opposite unpolished was used as the control. The refractive state and size of anterior opening were measured at postoperative 1 day as the baseline. Then they followed up at 1 month, 3 months and 6 months after surgery to record refractive state, higher-order aberrations, size of anterior opening, tilt and decentration of IOL (intraocular lenses)and PAD(postoperative aqueous depth). The paired t test was used to compare the differences between the two groups, and the same test the postoperative follow-up comparing with the baseline.

Myopia is the main reason of vision loss in the world which is seen in 30.4 million adults in USA (1). In a myopic eye, images are focused in front of retina because, cornea and crystalline lens become more powerful in focusing the image or the eye axis become too long (axial myopia) (2). Myopia prevalence in adolescents has been raised in recent years and nowadays it has reached to 10-25% and 60-80% in western and eastern countries respectively (3). Tehran eye study showed that the prevalence of myopia in Tehran is 21.8% and 17.2% based on manifest and cycloplegic refraction respectively (4). One study in Dezful, Iran showed that 3.7% of 7-15 years old children are myopic (5). Today potential role of early life nutrition in myopia development in later life is becoming an attractive field of study. It has been shown that until weaning; breast milk is the main source of many nutrients [such as docosahexaenoic acid (DHA)] which are important for photoreceptors and cortical neuronal development (6). But results about the relationship between breastfeeding and likelihood of childhood myopia are controversial. A hypothesis-generating study (7) showed an independent and inverse relationship between breastfeeding and likelihood of myopia in 10-12 year old Singaporean children. However, data pulled from three English birth cohorts done in 10-11y and 15-16y children did not show any effect (8). To examine the association between breastfeeding pattern and likelihood of myopia in 6-7y children, a retrospective case-control study is designed in National Nutrition and Food Technology research Institute of Iran. This study will try to assess breastfeeding pattern and almost all cofactors which may relate to myopia.

The purpose of this study is to analyze macular retinal thickness and macular volume using the spectral domain - optical coherence tomography (SD-OCT) in normal eyes and in eyes with various ocular diseases.

The purpose of this study is to test the hypothesis that myopia can be prevented by using a low concentration of atropine eyedrops once a week.

Control of myopia progression has become an important goal because of concerns regarding significantly increased risks of retinal degeneration, retinal detachment, glaucoma and cataract associated with high myopia. It is also clear there prevalence of myopia in children and young adults is increasing all over the world. Several methods including use of progressive addition lenses, rigid gas-permeable contact lenses, and life-style modifications (increased outdoor activity) have reported to alter myopia progression with varying efficacy. In general they have yielded clinical results of marginal significance. Atropine sulphate eye drops has consistently been demonstrated to inhibit axial myopia progression in both humans and animal models. Yet it has not found widespread clinical application for myopia control due to ocular side-effects of cycloplegia and pupil dilation. Recently 0.01% atropine has been shown to be effective in arresting myopia progression without side-effects of cycloplegia and near vision impairment and pupil dilatation and increased light sensitivity. Almost all studies on atropine have been carried out on children of Chinese origin. Efficacy (concentration and dosing) and safety need to be established in the population of interest, before routine use can be recommended. We plan to evaluate the efficacy and safety of topical 0.01% atropine eye drops in slowing the progression of myopia and ocular axial elongation in Omani children. A total of 150 children of ages 6-16 years will be randomized to two groups. Intervention group will receive atropine 0.01% once daily in each eye for two years (Phase 1). Control group will not receive any medications. Follow up visits will be scheduled every three months in Phase 1. Subsequently, medication will be stopped and the study patients will be followed up every six months for one year (Phase 2). The progression of myopia (change in refractive error and axial length) will be compared in the two groups by objective methods.

This is a bilateral, non-dispensing, randomized, controlled, double-masked, 7x7 cross-over study. Each subject will be bilaterally fitted with one of the 7 test articles in each of the 7 periods for a total of four visits. Up to two lens types will be fit at each of the four study visits.