View clinical trials related to Myopia.
Filter by:In Hong Kong, approximately 80% of children are myopic by the end of childhood. There is intense interest currently in the potential role of peripheral defocus as a clinical treatment to slow myopia progression. One of the most successful treatments for myopia is orthokeratology. Currently, Breath-O correct lenses are new designed ready-made orthokeratology lenses. This study is to evaluate the safety of wearing this new orthokeratology lens and the effectiveness of clinical performance in young adult.
This study will perform several objective and subjective measurements of the eye and vision before and after a week of using 0.01% concentration atropine drops. These measurements will help to obtain a comprehensive understanding of the side effects of this concentration of atropine and determine if the drops would be tolerated as a possible preventative treatment for nearsightedness.
Despite its prevalence, the ocular causes of eye fatigue or unknown and may be related to the cornea/contact lens surface, the accommodative system, the convergence system, overall postural/muscle fatigue, or a combination of these or other causes. The current study aims to systematically investigate the incremental benefits in ameliorating eye fatigue.
In the past two decades, the femtosecond laser (FSL) technology has been introduced in the corneal refractive surgery filed, and brought a remarkable innovation. It can make tissue dissection through photodisruption and plasma cavitation. Initially, the FSL was used predominantly to make a corneal flap when performing laser in situ keratomileusis (LASIK), which is followed by stromal ablation using excimer laser. A new surgical technique called femtosecond lenticule extraction (FLEx) has been developed that uses only FSL to dissect two interfaces to create refractive lenticule and then remove it, which is very similar with LASIK. Small incision lenticule extraction (SMILE) which is the advanced form of all-in-one FSL refractive technique does not make a corneal flap rather make small incision where the separated refractive lenticule is removed through, and the upper part of the corneal tissue is called cap. Since the clinical outcomes of SMILE were firstly published in 2011, SMILE has been widely used for correction of myopia or myopic astigmatism worldwide. SMILE provides excellent visual outcomes and has advantages including a lesser decrease in corneal sensitivity and absence of flap related complications compared to LASIK. Because corneal ectasia after refractive surgery is the one of most terrifying complication, corneal biomechanics has been drawn interests to many researchers and clinicians. Theoretically, SMILE may preserve corneal biomechanics better than LASIK, because the anterior stroma which is stiffer than the posterior stroma remains intact in SMILE. However, there are some controversies, because previous studies investigating corneal biomechanics have been reported inconsistent outcomes, although SMILE has been reported equal to or better than LASIK. Weakening of corneal biomechanics and iatrogenic corneal ectasia have also been reported after SMILE. In addition, because the tensile strength of cornea gradually decreases as it goes backwards, creating deeper refractive lenticule may result in stronger cornea by preserving more of anterior lamellae of the cornea. But on the contrary, leaving sufficient residual stromal bed has been known to be important in preventing iatrogenic corneal ectasia, hence creating thin cap may be effective and desirable. Although many researches have been investigated the difference in biomechanical response between SMILE and LASIK, there are few studies evaluating the dependence of cap thickness on postoperative biomechanical strength after SMILE. El-Massry et al. reported that the thicker cap thickness showed higher postoperative corneal hysteresis (CH) and corneal resistance factor (CRF) with Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Depew, NY) which may not be optimal for a clear description of the viscosity and elasticity of the cornea,3 ; however, other studies have been presented that there is no significant difference of corneal biomechanics with cap thickness. There is no comparative human study using Corvis ST (Oculus, Wetzlar, Germany) despite presence of the study using Corvis ST in rabbit eyes. Furthermore, no prospective study with large number of subjects has been performed to date.
PURPOSE: The aim of the study is to compare visual acuity means, refractive results, safety, and efficacy of TPRK with AAPRK as primary outcomes and surgical time, pain scores, haze levels, and healing time as secondary outcomes. SETTING: Security Forces Hospital, Ophthalmology Department, Riyadh, Kingdom of Saudi Arabia. DESIGN: Prospective, consecutive, nonrandomized case-control comparative study. . METHODS: A total of 200 eyes of 100 patients were included. One hundred eyes underwent TPRK in the right eye (study group) and 100 eyes underwent AAPRK in the left eye (control group). Ablations performed with the Schwind Amaris, 750S. Clinical outcomes were compared Paired student's t-tests and Mann-Whitney tests were used for statistical analysis.
Atropine eye drops are considered to be an effective form of myopia control in human eyes. However, the mechanism by which it exerts it effects are not fully understood. Thickening of the choroid subsequent to atropine administration may play an important role in the mechanisms by which atropine induces myopia control. Literature also notes that choroidal thickness undergoes diurnal variations, which is a variable that will be controlled in this study in order to examine atropine's effects on different baseline choroidal thicknesses. The purpose of the proposed study is to characterize better the influence of atropine on choroid thickness. The study aims are to: 1. Determine the effect of low dose concentration of topical atropine (0.1% and 0.01%) on choroid thickness 2. Determine the effect of topical atropine on choroid thickness in relationship to baseline thickness throughout the day and after one week of daily instillation Hypothesis: Atropine's effect on choroidal thickness will be dependent on the subject's baseline thickness measurements, at a designated time of the day when the choroid is at its thinnest.
The purpose of this study is to investigate if the blue-light filtering spectacle lenses promote myopia progression in schoolchildren.
The purpose of this study is to evaluate the overall performance of investigational contact lenses (DD T2) when compared to clariti® 1 day contact lenses.
Prospective, comparative, randomized, non-masked clinical study to compare the a digital refraction with LogMAR VA testing utilizing trial lenses, to standard manual refraction using a Phoropter, and LogMAR VA testing, in accuracy of visual acuity measurement.
Evaluation of the clinical performance of an investigational silicone-hydrogel contact lens (test) compared to a marketed lens (control), when worn on a daily basis for 1 month.