Active clinical trials for "Keratoconus"

This study is being performed to evaluate the efficacy of ultraviolet-A (UVA)-induced cross-linking of corneal collagen (CXL) in strengthening and optimizing the biomechanical and biochemical stability of the cornea in patients with fruste keratoconus (FFKC), corneas that are suspicious for FFKC and corneas thought to be at higher risk of developing ectasia that will be undergoing laser vision correction.

This study will be performed on patients who come to labbafinejad ophthalmic clinic from 20 March 2008. Keratoconus diagnosis will be determined by clinical finding in slit lamp, keratometery and topographic characteristics. Patients will be randomly placed in group A and B. In group A, Anwar surgical method and in B, Melles surgical method, will be done. This is not a blind study due to surgeons' knowledge. All patients will receive Btamethazone drop and Chloramphenicol every 6 hours and will be tapered in two months. In the end anatomical results, complications, BCVA, UCVA, astigmatism, endothelial cell numbers will be compared in two groups by using specular microscopy. Contrast sensivity, central corneal diameter, interface wrinkling and opacity will be measured by metrovison, Confoscan, Photoslit in months 3, 6, 12, respectively and will be evaluated afterwards.

This prospective study the thyroid gland dysfunction and vitamin D receptor polymorphism in keratoconus patients

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.

Certain studies reported that cigarette by-products may make the cornea more rigid, suggesting that it could lead to "natural" CXL of collagen fibers, hence a protective effect for KC. Others have reported that cigarette smoking causes no significant changes in the corneal biomechanics. The aim of this study was to assess a possible link between keratoconus (KC) occurrence and patients' smoking habits.

Keratoconus is a progressive ectatic disorder that steepens the cornea resulting in a conical shape. Radial Keratotomy can provide an optical rehabilitation by its flattening effect. It can also halt the progression of disease owing to fibrotic activation in perpendicular corneal incisions.

The investigators aim to investigate the effects of combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation in patients with moderate keratoconus. Medical records of 23 eyes of 23 patients undergoing combined tPRK and CXL after ICRS implantation were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, higher-order aberrations (HOAs), and corneal biomechanical properties were evaluated before and after ICRS implantation, and at 1, 3, and 6 months after combined tPRK and CXL. Corneal biomechanical properties were measured using the dynamic Scheimpflug analyzer at approximately the same time of day.

Keratoconus is a progressive corneal disease characterized by asymmetric corneal thinning and structural changes in corneal collagen which leads to decrease in visual acuity due to myopic shift, irregular astigmatism or corneal scarring. Early detection of the disease in children aids in halting the progression and improve their quality of life. There is no consensus regarding the progression criteria of the disease, we aimed to assess the changes in corneal asphericity in children after corneal collagen crosslinking and investigate any possible correlation with progression criteria widely used.

Keratoconus (KC) is a corneal disease which will in many cases ultimately require corneal transplantation to maintain vision. Early detection, which is not possible with current technology, would allow early treatment and prevent severe damage to KC corneas inadvertently operated upon for correction of vision. The investigators' aim is to combine measurements of different properties of the cornea to develop means for early detection of KC.

The aim of the present study is to develop a protocol for optimal corneal 3-dimensional imaging based on measurements in healthy volunteers. For this purpose, a customized ultra-high resolution Spectral Domain OCT will be used. To validate whether the protocol can also be applied in patients with corneal pathologies, for whom it is intended to be used, measurements in these patients will be performed. We propose to obtain images from patients with keratoconus, since this is one of the most frequent causes for corneal transplantations in Europe and from patients with corneal neovascularization which is a major cause of vision loss in several ophthalmic diseases. Based on the obtained measurement protocol, further studies investigating the pathophysiology or treatment success of several corneal pathologies can be planned.