Active clinical trials for "Keratoconus"

The investigators will evaluate 30 patients with surgical indication for corneal transplantation. Participants will be divided according to the following diseases diseases: keratoconus, bullous keratopathy, corneal dystrophies. Participants will be informed about the risks and benefits of the study and sign an informed consent form. In the preoperative evaluation will be submitted to a complete ophthalmologic examination with complementary tests, such as optical coherence tomography. One group of participants will undergo corneal surgery using the OCT Lumera microscope RESCAN - ZEISS and another group with a conventional microscope. Everyone will have their filmed and documented surgery. The team of surgeons will answer the questionnaire on the surgical difficulty about the ease of assessing corneal transplantation. After surgery, participants will be assessed on days 1, 7,15, 30, 60, 90 and 180 after surgery. Surgeries and study procedures will be performed by the same team of surgeons and performed by IPEPO - Paulista Institute of Studies and Research in Ophthalmology / Vision Institute.

Various approaches, including surgical and non-surgical management have been proposed for keratoconus. One of the surgical procedures is Intrastromal Corneal Ring implantations that have been designed to achieve refractive readjustment by flattening the cornea. There are different models of Intrastromal Corneal rings available: intrastromal corneal ring segments (ICRS) such as Keraring and intrastromal corneal continuous ring (ICCR) like Myoring. Most studies of these two types of ring implantation outcomes are retrospective case series. Thus, this Randomized Clinical Trial study was designed with the aim of Comparing visual and refractive outcomes and complications of insertion Myoring versus Keraring using Femtosecond laser. Keratoconus patients with compound myopic astigmatism who meet the inclusion criteria will randomly allocated to the Keraring and Myoring groups. Subsequently, the clinical outcomes of two groups will be compared at one,3 and 6 months after surgery.

The purpose of this research study is to find out if the new Brillouin Ocular Scanner can measure the variation (difference) of the corneal elastic changes involved in the onset of corneal ectasia, induced by LASIK surgery and cornea collagen crosslinking (CXL) treatment. Ectasia refers to the thinning and bulging of the cornea and results in severe vision degradation (loss), which may occur because of a progressive disease (keratoconus) or because of LASIK surgery. It is believed that the structural weakening of the cornea plays a major role in developing ectasia. CXL is a treatment that is able to halt the progression of ectasia. The Brillouin Ocular Scanner is a technique based on the principles used in the laser speed measuring of a car (radar gun). When laser light illuminates a moving sample, a portion of the light slightly changes color. In our body, e.g in eye and corneal tissue, very weak sound waves are naturally present and they can induce a similar color shift. Measuring this color shift with a sensitive light color meter (spectrometer), we will measure the sound speed in the tissue.

Compare different corneal parameters and visual outcome of corneal collagen cross-linking (CXL) with conventional versus accelerated ultraviolet-A irradiation using riboflavin with hydroxypropyl methylcellulose.

Immune rejection episodes after penetrating keratoplasty occur in 30% of patients and constitute one of the main factors reducing graft survival. They mainly occur during the first 18 months. Prevention usually relies on a topical treatment with dexamethasone or prednisolone for standard risk patients. Eye drops are instilled three times a day during at least 3 months then tapered. OZURDEX is an absorbable small implant that releases a total of 700 micrograms dexamethasone during several months. It is indicated for intravitreal injection to treat macular edema. The investigators hypothesized that this implant could be used after subconjunctival injection during corneal graft, to prevent immune rejection and avoid repeated eyedrop instillations.

Customized remodeled vision (CuRV) is a new corneal cross-linking protocol for keratoconus, combining a transepithelial approach with customized energy application. Our aim is to follow-up our patients and establish the short-and long-term results of CuRV.

It is aimed to investigate the role of supplemental systemic oxygen therapy during accelerated corneal collagen crosslinking (CXL). In this prospective randomized clinical trial, patients with progressive keratoconus who are candidates for receiving CXL will be included. The patients will be randomized and allocated to three different CXL protocol. In the first group (OA-CXL), CXL is performed using an accelerated protocol (9 mW/ CM2 for 10 minutes) in addition to the delivery of systemic oxygen with a rate of 5 liters/min through a nasal mask for 10 minutes during UV-A ablation. Patients in the second group (A-CXL) will receive CXL with the same accelerated protocol without additional oxygen therapy. Conventional CXL using 30 mW/CM2 UV-A ablation for 30 minutes is perfomed in the patients of the third goup (C-CXL). Maximum keratometry in Sirius corneal tomography as the primary outcome and uncorrected and corrected distance visual acuity (UDVA, CDVA) and corneal biomechanical properties including corneal resistance factor (CRF) and corneal hysteresis (CH) as secondary outcome measures are followed for a six- and 12-months period. A P-value of less than 0.05 is considered as statistically significance level.

The EYESTAR 900 with software version i9.5.1.0 includes new analysis functionality. Since its clinical performance cannot be assessed based solely on clinical literature as found in the Clinical Evaluation Report, further data from a clinical trial is required. The objective of this trial is to assess the clinical performance of the new features of the EYESTAR 900 with software version i9.5.1.0. This study is a necessary part of the clinical evaluation process of the investigational device. The results of this study are used for the clinical evaluation, and for reporting of in-vivo repeatabilities in the instructions for use of the investigational device, as required by topography standards.

The objective of this study is to assess the outcomes between deep anterior lamellar keratoplasty using dehydrated versus standard organ culture stored donor corneas.

The primary objective of this study is to evaluate two different ultraviolet (UV) dosing regimens for corneal collagen cross linking to slow the progressive changes in corneal curvature in eyes with progressive keratoconus or post-refractive surgery ectasia.