Active clinical trials for "Refractive Errors"

This study will evaluate the ability of toric multifocal contact lens to reduce the change of myopia progression in children (aged 8-12) with myopic astigmatism.

Study Objectives To compare the efficacy and safety of surgical treatment (PRK) versus non-surgical treatment of anisometropic amblyopia in children who have failed conventional treatment due to non-compliance or non-response. Synopsis of Study Design The study consists of two phases: A Patching Run-In Phase during which all participants are treated for at least 8 weeks with continued refractive correction (with spectacles and/or contact lenses) and patching prescribed 42 hours per week (averaging 6 hours daily) until no further improvement over 2 consecutive visits at least 4 weeks apart or the vision no longer meets eligibility criteria. A Randomized Trial Phase, beginning after no further VA improvement in the patching run-in phase and qualifying amblyopia is still present, during which the participant is assigned to either surgery with PRK and patching prescribed 2 hours per day or to non-surgical treatment with continued refractive correction (with spectacles and/or contact lenses) and patching prescribed 2 hours per day.

This study is planned to test an educational intervention promoting the use of spectacles among secondary school children. It is based on the hypothesis that educating teachers, parents and children about the importance of wearing spectacles has the potential to increase spectacle wear among children.Reasons for non-compliance towards spectacle use will be explored and educational intervention will be planned considering these reasons. Educational intervention will increase awareness about the importance of spectacles use and reduce the barriers towards spectacle use.Reducing barriers will increase compliance towards spectacles use which will ultimately prevent the avoidable visual impairment.

The vast majority of blindness is avoidable. The World Health Organization (WHO) estimates that 80% of cases of visual impairment could be prevented or reversed with early diagnosis and treatment. The leading causes of visual impairment are cataract and refractive error, followed by glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR). Loss of vision from these conditions is not inevitable; however, identifying at-risk cases and linking cases with appropriate care remain significant challenges. Worldwide, eye health care systems must determine optimal strategies for reaching people outside of their immediate orbit in order to reduce visual impairment. Visual impairment can be reduced by case detection of prevalent disease like cataract and refractive error, or by screening for early disease like glaucoma, AMD, and DR and preventing progression. Systems around the world have developed numerous approaches to both case detection and screening but there is very little research to support the choice of allocating resources to case detection or screening and little data exists on the cost effectiveness of the various approaches to each. VIEW II Pilot is a cluster-randomized trial to determine the effectiveness of different approaches to community-based case detection and screening for ocular disease. Communities in Nepal will be randomized to one of four arms: 1) a comprehensive ocular screening program, 2) a cataract camp-based program, 3) a community health worker-based program, and 4) no program.

The objective of this clinical study is to evaluate the safety and effectiveness of subepithelial implantation of the Allotex TransForm corneal allograft (TCA) for improving near vision in presbyopic subjects.

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 examine the short-term protective effect of Ultra-Violet filtering contact lenses on macular pigment ocular density.

The study aim to determine the prevalence of refractive errors in primary school children aged 6-12 in The New Valley , Egypt .

Identification of the correlation between angle kappa , corneal high order aberrations and total eye aberrations in myopic hyperopic and astigmatic patients

This study intends to analyze the characteristics between peripapillary retinal nerve fiber layer thickness and peripapillary area in high myopia with or without glaucoma