View clinical trials related to Keratoconus.
Filter by:The most common causes for irregular cornea (IC) in hospital contact lens practice are Keratoconus (KC) and related cornea thinning disorders. These conditions cause mild to marked impairment of vision and cannot be effectively corrected by spectacles and soft contact lenses. The gold standard in the management of KC is Corneal Rigid Gas Permeable contact lenses (corneal lenses), which correct approximately 90% of the corneal irregularity. Compared with a normal cornea, the cornea in KC is irregular and this results in a compromise to the fit of rigid corneal lenses. Specifically, they bear on the cornea and this, together with the vulnerability of the cornea in KC, are implicated in corneal scarring, and disease progression as well as a significantly reduced vision related quality of life (QoL) in KC compared with corneal lens wearers who have no KC. In cases where the compromise fit of corneal lenses proves problematic, large diameter Scleral RGP contact lenses (scleral lenses) may be used as a problem solver. Unlike the smaller corneal lenses which bear on the cornea, the scleral lenses completely bridge over the cornea and bear on the sclera. The aim of this research is to investigate the performance of scleral lenses in KC participants who habitually wear corneal lenses. The research question: is there a measurable difference in the visual performance and visual quality of life in participants with Irregular cornea disorders like keratoconus and other related conditions, who habitually wear corneal lenses in comparison with scleral lenses.
The measurement of visual acuity is made using black letters of varying size superimposed on a uniform white background. The objective is to determine the smallest letter, or optotype, that can be correctly identified. One limitation of current tests is the variability of measurements, this making it difficult for clinicians to determine if changes in visual acuity are related to ocular disease. This variability has been attributed to the design of current optotypes, in particular their differing legibilities. Our group has recently demonstrated that a new type of letter chart (Moorfields Acuity Chart), containing letters with a black core and a white border presented on a grey background, reduces the variability of visual acuity measurements. In this study the investigators wish to determine if changes in vision owing to keratoconus, a disease that causes the cornea to adopt an irregular shape, may be detected more easily using the Moorfields Acuity Chart compared with conventional letter charts.
The purpose of this retrospective study is to assess corneal changes (keratometry, pachymetry) and change in visual acuity (VA) in keratoconus patients after unilateral crosslinking treatment compared to the untreated fellow eye. The corneal measurements obtained preoperatively and 2 to 14 months postoperatively using a Pentacam rotating scheimpflug camera are analyzed. Furthermore, pre-existing or actual ocular pathology or/and ocular surgeries as potential factors involved in treatment outcome are also evaluated.
The purpose of this study was to determine whether mechanical compression of the cornea during corneal crosslinking for keratoconus using a sutured rigid contact lens can improve the optical outcomes of the treatment.
The gold standard corneal crosslinking (CXL) technique involves the initial step of epithelial removal, in order to achieve a sufficient treatment effect (meaning: stabilisation of progressive keratoconus (KC). Our aim is to evaluate the effects of transepithelial CXL (TE-CXL), whereby the epithelium is left intact and the cornea is instead treated by a solution composed of 0.1% riboflavin, combined with enhancers, after which standard CXL is performed. This solution seems to facilitate riboflavin penetration into the corneal stroma through the intact epithelium. The investigators expect to achieve a similar effect of TE-CXL with the advantage of a faster healing time and less risk of infections.
The purpose of the study is evaluating safety and clinical efficiency of full femtosecond laser-assisted anterior lamellar keratoplasty (FS-ALK) for curing patients with keratoconus and corneal opacities
Young patients with keratoconus face two problems: disease progression and corneal shape irregularity leading to poor vision even in spectacles. Corneal collagen cross-linking (CXL) is a new treatment designed to halt disease progression in keratoconus. The aim is to stiffen the cornea thereby preventing further shape deterioration. Topography or wavefront guided transepithelial photorefractive keratectomy (transPRK) uses the excimer laser (the laser used to correct sight in 'laser eye surgery') to reduce corneal shape irregularity in early stage keratoconus, reducing dependence on contact lenses. In transPRK, the corneal skin layer is removed in a well controlled, no touch procedure, preparing the cornea for CXL. Performing both treatments simultaneously (combining both procedures in one operation) may offer several advantages over performing CXL first then waiting for corneal shape to stabilise before performing transPRK. In particular, visual rehabilitation may be faster. This study aims to evaluate visual recovery after simultaneous CXL and transPRK in progressive early stage keratoconus. Visual recovery in these patients will be compared with results for a similar group of patients with early stage keratoconus who have already been treated with CXL alone.
Evaluation of the safety and efficacy of surface ablation followed by Collagen Cross-linking in patients with keratoconus
Laser- assisted procedures in penetrating keratoplasty (PK) are proposed to improve the surgical outcomes: minimally invasive procedures, improved biomechanical stability of the transplanted flap, reduction of rejection risks, reduction of inflammation, reduction of infections risk, faster healing process. In order to achieve these goals, two different lasers were used during PK surgery: - a femtosecond laser to cut an anvil shaped profile - a diode laser to weld the surgical wound
The US food and Drug Administration (FDA) originally approved INTACS prescription inserts in April 1999 for the correction of low levels of nearsightedness (-1.00 to -3.00 diopters). Additional clinical data have shown that INTACS are safe for the treatment of keratoconus, in July 2004, FDA approved INTACS inserts for the treatment of keratoconus as a Humanitarian Use Device (FDA approval letter attached). The statute and the implementing regulation of FDA (21 CFR 814.124 (aj) require IRB review and approval before a HUD is used.INTACS prescription inserts are composed of two clear segments, each having an arc length of 150°, they are manufactured form a biomedical material called polymethylmethacrylate (PMMA) and are available in three thicknesses. Two INTACS inserts ranging from 0.250mm to 0.350mm may be implanted depending on the orientation of the cone and the amount of myopia and astigmatism to be reduced.