Active clinical trials for "Keratoconus"

Keratoconus is a progressive disorder in which central and paracentral corneal stromal thinning occurs. No studies evaluated the influence of keratoconus on stress at work, nor the influence of treatments of keratoconus on stress at work, including Quality of Life at work and on perception of work. Moreover, it has been shown that some pathologies had greater influence in some occupations, also depending on other characteristics of individuals such as age, sex or socio professional groups. Therefore, we hypothesized that keratoconus 1) will influence stress at work including QoL at work and perception of work, 2) will have a greater influence in some occupations and depending on age, sex, or stage of keratoconus, 3) will induce stoppage of work and occupational reclassifications.

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.

This retrospective study aims to investigate whether the MS39 and Pentacam are delivering comparable results in the diagnosis of keratoconus. In the future, these measurement devices could be interchangeable in usage.

This study aims to use Schiotz tonometer to evaluate the corneal biomechanical properties. The administration of Schiotz tonometer is according to the routine protocol which is use to measure intra-ocular pressure. The results obtained from Schiotz tonometer will be compared with results obtained from ORA and/or Corvis.

Corneal transplantation have been performed for several decades, follow-up time in some centers now exceeds 30 years. Published long term (10 years and up) graft survivals vary considerably from center to center. These variations may be explained by differences in case-mix and surgical techniques used. The investigators aim to better understand the factors associated with long term graft survival.

To report three year follow up in pediatric patients with keratoconus after iontophoretic transepithelial corneal cross-linking (CXL) to assess preoperative factors that may influence ectasia progression

Keratoconus is a progressive bilateral disease leading to an apical stromal thinning and an irregular astigmatism by a steepening of the cornea, causing visual impairment. The causes are not yet well known, but it seems to be linked to several comorbidities. Keratoconus is a rare and for a long-time asymptomatic condition and its diagnosis needs meticulous screening for the early stages. Detecting it as soon as possible is a goal as it could lead to earlier avoiding of contributing factors such as eye rubbing and earlier treatment if needed. The gold standard for keratoconus screening and staging is computerized videotography. It gives information about anterior and posterior corneal bulging, steepening, and thinning. It can be completed by anterior segment optical coherence tomography, which can show corneal scarring. Since recently, some biometry devices can give some information about the posterior corneal keratometry trough swept source optical coherence tomography measures. The measurement of the total corneal power instead of an extrapolation lead to better precision in refractive results after cataract surgery in some cases. It also helped to increase our knowledge about posterior corneal astigmatism. In normal eyes, average posterior corneal astigmatism is 0.37 diopters and against the rule in 91 percent of eyes. There is a correlation between the magnitude of anterior and posterior astigmatism. In keratoconus eyes, several studies have shown that there is an alignment between axes of the anterior and posterior corneal astigmatism. These studies have been performed on computerized videotopography devices. The goal of this study was to confirm or deny previous observations about posterior astigmatism in keratoconus eyes, and to assess if the rotation of axis between anterior and posterior astigmatism measured by IOL Master 700® can be a good sign for detection of early stages and fruste keratoconus.

In keratoconic eyes, the corneal epithelium shows a localized thinning over the cone that is surrounded by an annulus of epithelial thickening. It has been postulated that epithelial thickness mapping can be a sensitive tool for the keratoconus diagnosis. In keratoconus screening the 5 mm diameter of the corneal centrum may be sufficient while studies have shown that the cone apex is located in this area. Aim of this study is to assess agreement and repeatability of epithelial thickness measurements using two optical coherence tomography devices in healthy and keratoconus corneas. Secondary objective is to evaluate the differences between healthy and keratoconus eyes using epithelial thickness map data. This is a prospective monocentric study that includes patients divided into two groups: patients with keratoconus and a control group formed out of patients without corneal pathologies. For each patient only one eye will be included and corneal measurements will be performed, focused on the corneal epithelium thickness.

Primary objective of this study was to assess the intrasession, intersession and interobserver variability of the Pentacam-derived curvature and zernike coefficients in back surface of normal, keratoconic and crosslinked corneas.

The purpose of this study is to properly analyse the visual and refractive outcomes of implantation of KeraRing intrastromal corneal ring segment (ICRS) at the different stages of keratoconus.