View clinical trials related to Myopic Astigmatism.
Filter by:The goal of this observational study is to test whether surgeries for lenses designed to be implanted in the eye to correct refractive error can be done without the need for using viscoelastic substances that are used routinely nowadays to make it easier to introduce them inside the human eye and protect the inside of the eye during the operation. The main question it aims to answer is that is it safe to do the surgery without using them? to answer this question researchers will access recorded data of patients that underwent refractive surgeries in a private clinic since 2017 and compare them as two groups: those who underwent the traditional procedures and those who had it without the use of dispersive viscoelastics in regard to their vision before and after surgery, their ocular pressure and biomicroscopic analysis of the inside of their corneas before and after surgery.
The goal of this observational study is to learn about the difference of refractive outcomes between Artificial Intelligence and experienced surgeon predicting Nomogram assist SMILE surgical design and the influenced factors of refractive outcomes in patients who underwent Small Incision Lenticule Extraction(SMILE) at the Refractive Surgery Center of Tianjin Eye Hospital. The main questions it aims to answer are: - Compare the difference of refractive outcomes between Artificial Intelligence and experienced surgeon predicting Nomogram assist SMILE surgical design - Analysis the influenced factors of refractive outcomes
Small incision lenticule extraction (SMILE) is a refractive intrastromal procedure for myopia and myopic astigmatism correction. Most of the studies evaluating astigmatic correction by SMILE reported astigmatic under-correction, especially in high degrees of astigmatism. This under-correction could be due to: first, the active eye tracker or the iris registration is not yet available to overcome the cyclotorsion that occurred during the treatment with the VisuMax femtosecond laser system (Carl Zeiss Meditec, Jena, Germany) which could be overcome by manual compensation technique, especially in higher degrees of cylinders (> 1.5 diopters (D)). Second, in patients with small lenticule diameters, the more abrupt change in thickness at the edge of the treated area could induce more stromal and epithelial healing in this area. Thus, the astigmatic correction would be less effective with small than large lenticule diameters for similar high preoperative astigmatism. This study assessed the outcome of using a 0.5 millimeter (mm) larger lenticule diameter in the fellow eyes of myopic astigmatic correction SMILE participants. This assessment included the safety and effectiveness indices, the refractive and visual outcomes, the contrast sensitivity, and some morphological outcomes such as corneal curvature and epithelial and corneal thickness.
This prospective non-comparative interventional study aims to analyse the pre-operative factors affecting the range of optimal ICL vaulting. the main question is what is the correlation between age, gender, spherical equivalent, white to white, anterior chamber volume and depth and postoperative vault? participants will do preoperative investigations ( specular microscopy, pentacam and biometry ) then refractive surgery (ICL implantation) followed by follow-up visits to assess the post-operative ICL vault and visual outcome.
In this multicenter, prospective, interventional, single-arm clinical trial, the aim is to determine safety and efficacy of CLEAR using the FEMTO LDV Z8 in Chinese patients in China. The primary objective is to evaluate the visual outcome after CLEAR using the FEMTO LDV Z8 in myopia and astigmatic myopia at the time point, when stability of manifest refraction spherical equivalent (MRSE) is reached. The corresponding hypothesis is that the percentage of treated eyes with satisfactory Uncorrected Distance Visual Acuity (UCDVA) at the point when stability of MRSE is reached after CLEAR is at least 85% of all treated eyes. This hypothesis has been chosen in line with the recommendations of the "Checklist of Information Usually Submitted in an Investigational Device Exemptions (IDE) Application for Refractive Surgery Lasers" issued by the FDA. The secondary objectives are to evaluate the efficacy and safety with respect to stability, predictability, device defects and adverse events of CLEAR using the FEMTO LDV Z8 in myopia and astigmatic myopia during follow-up.
The recently introduced toric V4c toric ICL (STAAR Surgical Company, Monrovia, CA, USA) has been designed with a 360-µm central hole to allow aqueous humor to flow without the need for an iridotomy. As far as the investigators certain, there have been not well-established prospective studies on the role of the V4c toric ICL for myopic astigmatism correction. Therefore, the present study aimed to investigate the clinical outcomes and rotational stability and to analyze factors that influence the rotational stability in V4c toric ICL implanted eyes prospectively.