View clinical trials related to Myopia.
Filter by:As new orthokeratology fitting software emerges onto the market, it is of interest to assess their usefulness in guiding eye practitioners with lens fit. The goal of this study is to evaluate the comfort of Paragon orthokeratology lenses when they are fit using the new Procornea software.
Atropine is a non-selective muscarinic acetylcholine (M) receptor antagonist that paralyzes the ciliary muscle, dilates the pupil, and reduces the power of accommodation. Current studies have confirmed the effect of low concentrations of atropine drops in slowing the progression of myopia. In the atropine treatment for myopia (ATOM2) study, there was a rapid and dose-dependent decrease in accommodation after atropine drops: after 2 weeks of use, accommodation decreased from baseline 16.2D to 11.3D (4.9D) in the 0.01% atropine drops group, from baseline 16.7D to 3.8D (12.9D) in the 0.1% atropine group, and from baseline 15.8 D to 2.2 D (13.6 D) in the 0.5% atropine group; one year after withdrawal, there was some recovery of the accommodation in all the three groups, but it was still lower than the baseline values for each group, with a mean decrease of 2.56 D.Similar results were found in the Low-concentration Atropine for Myopia Progression (LAMP) Study by Janson C. Yam, 0.05% atropine drops reduced the accommodation by approximately 2D on average after 1 year of treatment. In general, if accommodation decreases by 2D or more compared to normal values, accommodation insufficiency is considered. There is a linkage between accommodation and convergence called accommodative convergence-to-accommodation (AC/A) which is closely related to exotropia. It was reported that the amount of accommodation required to maintain binocular fusion in patients with intermittent exotropia was greater than that of normal controls. In addition, pupil size and visual acuity are also factors that affect accommodation. In summary, the reduced accommodation amplitude, pupil dilation, and blurred near vision caused by atropine drops would affect the progression of intermittent exotropia and the ocular alignment after the surgery. In most cases, the reduced accommodation and convergence might induce exotropia, but in some patients, they may use more accommodative stimuli to compensate the insufficiency of accommodation, and there may be an increase in convergence or even esotropia. Taken together, due to the effect of atropine drops on pupil size, near visual acuity, and accommodation amplitude, the investigators hypothesize that atropine drops are likely to affect binocular vision and ocular alignment in patients with exotropia and exophoria.
Investigators are going to conduct a multi-centered randomized clinical trial that myopic children are randomly allocated into three groups: 0.01% atropine， 0.04% atropine and orthokeratology in order to evaluate the efficacy and side effects of different intervention methods and establish a risk factor model to predict the efficacy of myopia intervention, and to provide precise intervention plans and clinical decisions for the control of myopia.
The high prevalence of myopia has become a global public health problem. The study amied to investigate the prevalence and progression of myopia associated with social environmental factors in Tianjin, a Chinese megacity in north China.
The purpose of this post-approval study is to confirm the effectiveness of the MiSight 1 Day lens in clinical practices within the US and to assess the stability of the myopia reduction over one-year post-treatment.
The purpose of this post-approval study is to confirm the safety of daily disposable soft contact lens wear among the intended patient population for the MiSight 1 Day lens in the US.
The objective is to develop and evaluate an algorithm for implantable collamer lens (ICL) sizing that uses high frequency ultrasound biomicroscopy (UBM) for vertical placement.
The IOL-capsular complex is formed after cataract surgery and intraocular lens (IOL) implantation. Early postoperative mechanical wrapping of the anterior and posterior capsules plays a significant role in preventing IOL decentration and tilt, as well as formation of the IOL-capsular complex which reduces the incidence of posterior cataract opacity. IOL decentration ≥ 0.4 mm or/and IOL tilt ≥7degree were considered clinically significant cause of poor post-surgery visual quality especially for optical sophisticated IOLs. This negative impact does not affect various types of IOLs equally. Several studies indicated that AL was an independent risk factor of IOL decentration and tilt for emmetropic or moderate myopic eyes. For patients with high myopia, they often have a longer axial length and a larger capsule diameter, which reduces the rotational stability of the IOL and may lead to tilt, decentration and displacement of IOL. Currently, there is no literature guidance to compare the results of cataract surgery combined various types of IOLs implantation in patients with high myopia. The novel anterior segment optical coherence tomography (AS-OCT) device, CASIA2 can evaluate the IOL capsule bending and the lens position after cataract surgery. Also, CASIA2 can be used to documented the dynamic changes of IOL-capsular complex after surgery.
Myopia is the most common refractive eye disease worldwide. The number of cases is up to 2 billion. In recent years, the incidence of myopia in China is obviously rising trend. As early as the 2018 national health committee epidemiological data show that teenage myopia rate in China has been the first in the world, and has become the influence in China, especially the youth eye health major public health problem. In recent years, prevention and control measures for myopia have emerged in endlessly, such as increasing outdoor activity time, sufficient sunlight exposure, orthokeratology and local use of low-concentration atropine can partially prevent the occurrence or slow down the progression of myopia. But the effects are limited and cannot completely inhibit the development of myopia. In recent years, with the in-depth study of myopia, it is found that myopia is not only the change of diopter, but also the pathological changes of the whole eyeball shape and corresponding tissues. The incidence of myopia is closely related to the biological parameters of the eyeball, which has become a hotspot of clinical research in recent years. Current studies believe that eyeball biological parameters such as axial length, scleral thickness, choroid thickness are related to the occurrence of myopia, among which the change of scleral structure and shape, namely scleral remodeling, is considered to be an important factor in all visual stimuli leading to myopia. A large number of studies have also shown that scleral remodeling can lead to changes in the scleral biomechanics, thereby promoting the development of myopia. Multiple studies have shown a negative correlation between myopia and scleral thickness, with the thinning of the lower anterior sclera being the most significant. The lower anterior sclera is considered to be a marker for predicting the development of myopia, but some studies have found no correlation between the two. Such differences in the results may be related to the precision of the measurement instrument, the sample size of the included cases, age, and the grouping of different refractive states. The correlation between various biological parameters of the eyeball, especially the sclera, and myopia is not clear at present. Therefore, more penetrating and clearer instruments, more sample sizes, and more scientific grouping are needed for further research and confirmation.
Evaluation of the efficacy in decreasing myopia progression of the proposed ophthalmic lens prototypes.