View clinical trials related to Keratoconus.
Filter by:To assess depth of demarcation line in transepithelial versus epithelium-off accelerated cross-linking in keratoconus patients
Keratoconus is characterized by a thinning of the cornea, which causes a decrease in visual acuity due to astigmatism. Publications suggest that keratoconus is linked to chronic inflammation (increase in pro-inflammatory cytokines and metalloproteinases (MMP). Direct epithelial-stromal interactions (D-ESI) have a role in the induction of metalloproteinases (MMP) and the differentiation of fibroblasts into myofibroblasts via an EMMPRIN membrane glycoprotein (extracellular matrix membran MMP inducer - CD 147). On a healthy cornea, EMMPRIN's effects are prevented by a lack of contact between epithelial and stromal cells through a basement membrane, which is altered in the keratoconus The hypothesis is that stromal thinning of the keratoconus could be related to increased expression of EMMPRIN by epithelial and stromal cells (resulting in increased MMP synthesis), with a preponderance at the most deformed areas. The main objective is to demonstrate a transformation of fibroblasts to myofibroblasts in the corneal stroma of keratoconus patients.
The purpose of this study is to evaluate the efficacy, safety and postoperative ocular discomfort by comparing individually customized Photorefractive intrastromal crosslinking (PiXL) for progressive Keratoconus. The study compares two different protocols, PiXL with corneal epithelium debridement (Epi-off) and PiXL without epithelium debridement in high oxygen environment (Epi-on), with the hypothesis that Epi-on gives less postoperative ocular discomfort.
Aim of this study is to conduct longitudinal and cross-sectional analyses about the corneal ectatic disease Keratoconus based on data obtained from Keratoconus patients in the Homburg Keratoconus Center (HKC). The Homburg Keratoconus Center (HKC) was founded in 2010 and, up to now, comprises more than 2.000 Keratoconus patients. Topographic, tomographic and biomechanic characteristics of the disease are being analyzed with the intention to elucidate how the disease begins and develops during lifetime.
The study objective is to compare accelerated and standard corneal crosslinking for treatment of progressive keratoconus or corneal ectasia.
To determine whether the Peschke PXL-330 system is safe and effective in the treatment of corneal thinning conditions.
To our knowledge, this study is one of the first to compare the visual results of non-topography-guided and topography-guided photorefractive keratectomy (PRK) applying sequential and simultaneous corneal cross-linking (CXL) treatment for keratoconus. Considering recent advances in cross-linking and imaging in keratoconus, the outcomes of this study can lead us to several non-invasive algorithm management options.
Aim of work: - To detect abnormal corneal thinning in keratoconus using pachymetry maps measured by high-speed anterior segment optical coherence tomography (OCT). - To evaluate the visualization and depth of the demarcation line with anterior segment optical coherence tomography (AS-OCT) after corneal collagen cross-linking (CXL). - To compare the depth of demarcation line between epithelial-on (Epi-on) and epithelial-off (Epi-off) corneal collagen cross-linking.
This is a prospective, randomized, single investigative site study to compare the safety and effectiveness of Epi-OFF CXL treatment (performed using Ricrolin+ and VEGA UV-A system) compared to Epi-ON CXL (performed using Ricrolin+ and VEGA UV-A system) in eyes with keratoconus and other corneal ectatic disorders.Subjects will be randomized to receive the CXL treatment with either the Epi-On or Epi-Off technique.
Background: The objective of corneal collagen crosslinking (CXL) is to increase the binding of intrafibrillary and interfibrillary covalent bonds to improve the mechanical stability of the cornea and thus to stop the progression of corneal ectasias. Although the vast majority of studies have described pain after photorefractive keratectomy (PRK), the pathophysiological principle of pain is similar in CXL. From the anatomical point of view, the corneal epithelium is the most densely innervated and sensitive surface of the body, being 300-600 times greater than in the skin. The pain after CXL comes from several routes, the process begins with the epithelial rupture that generates exposure of the nerve endings, induces apoptosis and necrosis of the epithelial cells. Subsequently an inflammatory cascade is initiated in which the different cytokines stimulate the nerve terminals. Inflammatory mediators also activate the ion channels in the nerve membrane, and this process continues until the epithelium heals. Additionally, exposure to UVA rays can also cause nerve damage. The effect of local cold for pain management has already been reported in PRK. By cooling the cornea, the release of chemical mediators and inflammation can be reduced. In the CXL radiation is transformed into several forms of energy: fluorescent radiation, chemical energy and, to a small extent, heat. The CXL process is energetically comparable to photosynthesis, in which the radiation energy is transformed into chemical energy (glucose) with the help of pigments (chlorophyll). The thermal effect is negligible in the photochemical method of CXL. Justification: No method for the control of pain after crosslinking is considered ideal or universally accepted, the importance of this study lies in looking for an additional tool to reduce the most common postoperative complaint in a highly performed procedure worldwide. Hypothesis: The application of riboflavin at 4oC reduces the pain assessment after the CXL. Purpose: to evaluate the effect of the application of riboflavin at 4oC in the assessment of postoperative pain in patients undergoing CXL. Materials and methods: Prospective and interventional clinical study in patients older than 18 years with a diagnosis of keratoconus who underwent CXL, in the cornea and refractive surgery service of the Ophthalmology institute Fundación Conde de Valenciana.