View clinical trials related to Anisometropia.
Filter by:Amblyopia is a developmental condition that is characterized by reduced vision of the eye due to the presence of a sensory impediment during visual development, such as strabismus (ocular misalignment) or anisometropia (unequal refractive error), occurring early in life. Recent studies in humans and animals point towards a cortical locus for the processing deficit in amblyopia, revealing sensory deficits at the signal cell level. If changes in retinal neuronal function are also present, is unknown. Like in the brain, blood flow in the retina is coupled to neuronal activity. This phenomenon has been measured by different study groups with non invasive techniques in the brain and retina. It has been shown in previous studies that stimulating the retina with diffuse luminant flickering light increases retinal vessel diameter and blood flow. However, it is unknown whether this is also the case in the retina of amblyopic eyes. Additionally, the introduction of blood oxygen level dependent (BOLD) fMRI also makes it possible to directly access the vascular response in the brain to visual stimuli. Therefore, the aim of the present study is to investigate the effect of luminant flickering light on retinal vessel diameter and retinal blood flow in subjects with amblyopia. Also, oxygen saturation in retinal vessels will be assessed as well as pattern ERG for assessment of retinal function. Additionally, a high resolution image of the visual pathway will be taken with 7 Tesla MRI to investigate whether anatomical or functional alterations are present.
INTRODUCTION. Amblyopia is defined as the loss of visual acuity (VA) in one or both eyes, without any obvious structural or pathological anomalies. Amblyopic eye should be able to regain some VA if treatment is initiated before the age of seven. It is the leading cause of monocular blindness in the 20- to 70-year olds with prevalence 2-5%. Amblyopia is mainly monocular, hence children are general asymptomatic. VA testing is the only reliable method of detecting amblyopia, and the fourth year of life is considered best for vision screening programs. AIM: The purpose of the study is to reduce the preventable vision loss. The main goal of the study is to evidence the problem of amblyopia in Zagreb and to release a model for formal, government directed vision-screening program as a Croatian public health policy. HYPOTHESIS. In Croatia, the prevalence and actual effect of amblyopia and amblyogenic factors, along with treatment efficacy is impossible to quantify, since no population-based studies have been performed regarding this issue. In addition, national screening of preschool children does not exist, while the school-entry screening is prescribed by law. The object of the study is to determine the prevalence of amblyopia in a 4-4.5 year old children of The Town of Zagreb, the efficacy of screening and effectiveness of treatment on reducing amblyopia prevalence. The primary hypothesis is defined: screening of visual acuity monocularly at distance and near in 4-4.5 year old children in Zagreb is effective in detecting amblyopia. PATIENTS AND METHODS: Monocular vision of about 7000 children/ year aged 4-4.5 for whom both parents gave consent is to be tested with Lea chart at near (40cm) and distance (3m) in the kindergartens of The Town of Zagreb. The criterion for referral to complete ophthalmological examination is VA <0.8.
The purpose of this study is to determine the safety, efficacy, predictability, and stability of laser in situ keratomileusis (LASIK) to correct high anisometropia in patients 8 to 15 years old in whom conventional treatments have failed.
Our study has three parts has three parts, and the main aim of the study is to find out if corneal hysteresis was associated with myopia or even a predictor of myopia poor control predictor: - Part 1 of our study: patients with anisomeropia whose spherical equivalent refraction as measured by cycloplegic autorefraction between the two eyes differ greater than 1.5 D. - Part 2 of our study: Minus spherical equivalent refraction as measured by cycloplegic autorefraction. - Part 3 of our study: patients with minus spherical equivalent refraction as measured by cycloplegic autorefraction who are under regular atropine for the treatment of myopia;patients who are prescribed with atropine treatment are in need of myopia control instead of for research interest
The purpose of this study is to compare the results of two standard treatments for amblyopia in order to find out if one is more effective than the other. Amblyopia, which develops in childhood, is also called "lazy eye," because one eye is not being used properly. The brain favors the other eye for some reason, such as crossing or turning out of the eyes, and vision in the weak eye is reduced. Amblyopia is treated by forcing the child to use the weak eye. There are two ways to do this: 1) a patch placed over the "good" eye forces the child to use the weak eye; or 2) an eye drop placed in the "good" eye once a day to blur vision in that eye makes the child rely on the weak eye. The success rates with both of these methods have been reported to be about the same; this study will try to identify if one is more effective than the other. Children will be randomly assigned by computer to one of the following two treatment methods: Patch The child initially will wear a patch over the "good" eye for 8 to 12 hours every day. If vision in the weak eye improves, the patching time will be decreased. If vision remains good after 3 months, the patching will be stopped, unless the child's doctor believes treatment should continue. If vision in the weak eye does not improve, the patching time will be increased. Eye Drops The child will be given one drop per day of atropine in the "good" eye. If vision in the weak eye improves, the drops will be given less often. If the vision remains good after 3 months, the drops will be stopped, unless the child's doctor believes treatment should continue. If the initial daily drop does not improve the vision in the weak eye, the child's eyeglasses may be changed to try to further blur the vision in the "good" eye. After 6 months, treatment may be stopped if it has not been successful. If treatment has been successful after 6 months, it may be continued at a reduced amount or stopped. Follow-up visits will be scheduled every 4 weeks for the first 6 months and every 2 to 4 months after that until the end of the 2-year study. During each visit the eyes will be examined for eye movements and vision, and the pupils will be dilated to examine the inside of the eye.