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Showing 1-12 of 12 trials
NCT07549815
To evaluate the changes that occur in the intraocular pressure after corneal refractive surgery either PRK , LASIK and femtosecond laser by using Corvis CT results and applanation tonometer
NCT07544615
Significance, Background, and Current Status Studies show the global average prevalence of myopia is 22%, with hyperopia incidence being similar. In China, the myopia prevalence is 31%, making it one of the countries with the highest rates of myopia. Currently, the safety and efficacy of corneal refractive surgery (CRS), such as LASIK and SMILE, for correcting myopia, hyperopia, and other refractive errors are well-established. An increasing number of patients undergo CRS to alleviate the inconveniences caused by refractive errors. While LASIK has long been regarded as a classic procedure, since the first report of Small Incision Lenticule Extraction (SMILE) for myopia correction in 2008, it has evolved into one of the mainstream surgical techniques. With the rapid advancement of refractive surgery, minimizing postoperative complications while maintaining excellent visual outcomes has become a major focus for clinicians. Postoperative intraocular pressure (IOP) monitoring is a crucial observation index. Theoretically, IOP should not change significantly after CRS, as the surgery does not affect aqueous humor dynamics or intraocular volume. However, numerous studies indicate that alterations in corneal shape and biomechanical properties, particularly corneal thinning, lead to artificially low IOP readings with various tonometers, especially those dependent on corneal thickness. Furthermore, postoperative management often requires prolonged use of corticosteroid eye drops to suppress inflammation and promote wound healing. Extended steroid use can increase aqueous outflow resistance, elevating IOP, particularly in steroid responders, and potentially leading to steroid-induced glaucoma. Additionally, high myopia is a known risk factor for primary open-angle glaucoma. Therefore, based on preoperative and postoperative corneal parameter changes, rapidly and effectively determining the actual IOP range after CRS is of great significance for guiding clinical medication and screening for steroid-induced glaucoma. Big Data and Artificial Intelligence (AI) are increasingly applied in medicine. AI primarily includes two technical branches: machine learning (ML) and deep learning. ML, a novel AI technology, has garnered significant interest in medical applications in recent years. It typically involves computer simulations that integrate human-like learning, refine knowledge structures, and continuously improve performance to aid diagnosis and intelligent decision-making, becoming a pivotal method in AI. Resembling neural network processes, ML systems are trained on selected input data using appropriate algorithms to produce corresponding outputs. It is now widely used to solve complex problems in engineering and science. In ophthalmology, AI/ML has gained attention for assisting in disease detection and monitoring, demonstrating advantages in fundus image diagnosis, keratoconus screening, and glaucoma classification. In corneal refractive surgery, ML has been applied to preoperative parameter design and outcome optimization, showing good safety, efficacy, and predictability. Preliminary attempts have been made to use AI decision trees to evaluate the safety and efficacy of CRS. Building on this advanced technology and our previous research findings-which suggest that IOPcc and Pentacam-derived correction formulas (with the Shah correction method being preferable) provide relatively reliable IOP estimates after SMILE-this study aims to establish a data-driven model. Using Shah-corrected IOP as a reference to define postoperative IOP status, we will train and iteratively optimize a model by incorporating all relevant preoperative and postoperative parameters potentially affecting IOP. The goal is to predict the true IOP after CRS, thereby guiding postoperative follow-up, facilitating early detection of IOP elevation, and identifying potential glaucomatous tendencies.
NCT06818461
To evaluate corneal biomechanical changes using the Corvis ST in patients who have under-gone LASIK, PRK, and corneal cross-linking (CXL).
NCT05551715
Justification: Although great strides have been made in the past to develop VEMoS software, it has not yet been validated with actual clinical data from patients who have undergone cataract or refractive surgery. There are some fundamental questions that must be addressed to validate and update the software, such as the objective visual quality metrics that best predict the patient's post-surgical subjective vision from the predictions of the optical properties of the eye. The VEMoS software must be adjusted for different types of inputs and eye parameters: Corneal tomography of MS39-AXL MS39-AXL corneal tomography + biometric data from the IOL Master MS39-AXL corneal tomography + IOL Master biometric data + total aberrometry Combinations of any of the above with the optical properties of a specific IOL, etc. Objective The main objective is to standardize the selection of parameters to personalize refractive surgery, based on the biometric data of each patient. The objectives necessary to achieve such an ambitious goal are: 1. Redesign VEMoS software 2. Determine which biometric data, diagnostic tools, and objective and subjective metrics of visual quality are best for the selection of optimal refractive parameters for surgery 3. Optimize the combined use of biometric data, VEMoS software, and visual quality metrics Study design The proposed multicenter clinical trial is observational and prospective. There will be three arms within the clinical trial, a no-treatment arm, a refractive surgery arm, and a cataract surgery arm. Participants in the untreated arm will undergo an ophthalmic exam only once. Participants in the other two arms will undergo two ophthalmic exams, one before and one after surgery. For all participants, cataract or refractive surgery will be performed as part of routine clinical practice. Other additional tests performed are all non-invasive. Study population Untreated eye arm patients 18 to 40 years of age. Refractive surgery arm patients who are planned and have consented to a corneal refractive procedure to gain spectacle independence. Cataract surgery arm patients older than 50 years who are planned and have consented to cataract surgery. Sample size The sample sizes for each arm of the clinical trial are as follows. Untreated eye arm: The goal is to recruit 600 eyes from 300 patients, 100 patients in each of these groups: Myopia (from -10 D to -0.75 D) Emmetropia (from -0.5 D to + 0.5 D) Hyperopia (from 0.75 D to 5 D) Refractive surgery arm: For LASIK, the goal is to recruit 800 eyes from 400 patients, 100 patients in each of these groups: High myopia (from -10 D to -6 D) Medium myopia (from -6 D to -3 D) Low myopia (from -3 D to -1 D) Hyperopia (from +1 D to +4 D) For SMILE, the goal is to recruit 400 eyes from 200 patients, 100 patients in each of these groups: High myopia (from -10 D to -6 D) Average myopia (from -6 D to -3 D) For the cataract surgery arm: The goal is to recruit 400 eyes from 200 patients, 100 patients in each of these groups Zeiss monofocal IOLs multifocal IOL A total of 500 patients are expected between the Vissum, IMO and IOA clinics in Miranza. A total of 250 patients are expected between hospital and university of Coimbra epe (Portugal). A total of 350 patients are expected at Aarhus universitetshospital (Denmark).
NCT06625749
This is a study to evaluate the safety and effectiveness of the AccuraSee™ intraocular pseudophakic capsular lens (IOPCL) to improve near and/or intermediate vision following previous cataract surgery.
NCT04396990
To determine patient preference and treatment outcomes with an intracanalicular dexamethasone (0.4mg) insert compared to standard steroid drop regimen in the contralateral eye following bilateral PRK surgery.
NCT04130490
This is a prospective clinical study that will be conducted at one clinical site located in the United States to assess anterior segment parameters with the ANTERION
NCT05060094
To compare the quantitative and qualitative optical outcomes between single-step transepithelial photorefractive keratectomy (TransPRK) and off-flap epipolis laser in situ keratomileusis (Epi-LASIK) in moderate to high myopia.we included patients with moderate to high myopia who were randomized to have TransPRK in one eye and Epi-LASIK in the other eye. All patients underwent comprehensive ophthalmological examinations, including uncorrected (UDVA) and corrected distance visual acuities (CDVA), manifest refraction, intraocular pressure, anterior and posterior segment examination, corneal topography measured by Scheimpflug scanning-slit topographer (Pentacam, Oculus Optikgerate GmbH), contrast sensitivity (CS) under photopic and mesopic conditions (CSV-1000E, Vector Vision Inc., Greenville, OH, USA) with correction by spectacles, ocular wavefront aberrometry (OPD-Scan II, Nidek Co. Ltd). At each follow-up, CS and aberration measures were repeated 3 times and the average value was analyzed. Optical parameters were repeated 1, 3, 6, and 12 months after surgery.Statistical analysis was performed using SPSS software (version 22.0, SPSS, Chicago, Inc.). Kolmogorov-Smirnov test was used to check the normal distribution of variables. Student t-test or Wilcoxon rank sum test was used based on the normality of data. A P value less than 0.05 was considered statistically significant.
NCT03597906
Background and Rationale: LASIK has been among the highest satisfaction rates of surgical procedures, ranging from 82%-98%. Different ablation profiles have been developed over the years. The purpose of this study is to validate this novel measurement by comparing the visual outcomes when the TMR is used in myopic astigmatic LASIK to using the standard manifest refraction or the Topolyzer measurements alone. Objectives : To evaluate the safety, efficacy and predictability of topography-guided myopic LASIK with three different refraction treatment strategies.
NCT03791684
WHAT WAS KNOWN \*Standard CXL is the common procedure for treating progressive corneal ectasia. Modifications of the standard protocol were introduces to reduce its complications especially long exposure to ultraviolet rays. The Accelerated protocol, while believed to overcome this issue with comparable outcomes, has not been studied fully in patients with ectasia following corneal refractive surgery and penetrating keratoplasty. WHAT THIS PAPER ADDS Accelerated CXL is as safe and effective as the Standard CXL in halting the progression of ectasia post refractive surgery and penetrating keratoplasty with the benefit of: reduced ultraviolet exposure, reduced operation time, and reduced patient discomfort.
NCT02614625
An increasing number of clinical studies on SD-OCT of ocular pathologies and potential new clinical applications has recently been published in the peer-reviewed literature. However, the successful use of SD-OCT in routine clinical use depends upon the diagnostic sensitivity, biometric accuracy and reliability of the SD-OCT machines. This prospective, comparative, observational study aims to evaluate the imaging quality and diagnostic performance of two commercially available SD-OCT machines for both the anterior and posterior segment of the eye.
NCT01220193
The purpose of this study is to evaluate RTVue measurement of the cornea in various ocular conditions to include normal, pathology, post refractive surgery and cataract.