evaluation of tomographic and genetic aspects of keratoconus patients compared to sounds corneas

Conditions: Keratoconus; Keratoconus, Unspecified, Bilateral

Summary: evaluation of tomographic (pentacam) parameters and genetic parameters of visual system homeobox 1 (vsx1), superoxide dismutase (sod1), tissue inhibitors of metalloproteinases (timp3) genes of keratoconus patients diagnosed by clinical exam and topographic pattern. basically we are screening patients that don't have keratoconus that those have keratoconus. the pentacam index of corneal curvature, thinnest point, corneal high order aberrations, posterior and anterior elevation, corneal densitometry, corneal volume were investigated. to analyze the genes, we took corneal epithelium samples of patients submitted to cross linking compared to (prk) photo refractive keratectomy ones. also will be evaluated the genes of peripheral blood.

keratoconus is a common disease that affects the cornea in both genders in all ethnic groups and that can manifest unilaterally or bilaterally in patients. keratoconus due to a degenerative disease, its progression can be fast in various situations, affecting 1 in every 2,000 people, what results in severe structural changes of the cornea, which reduces its thickness and modify its normal curvature to a more conical shape. keratoconus arises in adolescence and lasts for thirty to forty years of age, where it stabilizes and it is considered a major cause of corneal transplantation. factors such as atopy, overuse of contact lenses and the act of rubbing the eyes are also related to the disease. the clinical picture consists of a lot of varied symptoms and it depends on the stage of disease progression. currently it is known that genetic and environmental factors are involved in the desease emergence. recently several genetic studies have aimed to identify mutations in genes which are directly linked to keratoconus, such as vsx1, sod1 and timp3 genes. however, despite the efforts directed towards the understanding of the genetic aspects of this disease, involving many genes, there are still many questions about the role of these genes in keratoconus etiology. thus, the present study aims to identify the presence of mutations in vsx1, sod1 and timp3 genes, which are considered important candidates for the origin and development of this eye anomaly, through the analysis of their nucleotide sequences in corneal tissue and peripheral blood in keratoconus patients, in their unilateral and bilateral forms. the results will allow to compare the presented mutations in different analysed tissues for unilateral and bilateral forms of keratoconus and also compare them with the same tissues in healthy patients, in an attempt to establish what the likely inherited and/or acquired genetic mutations are causing this condition. thus providing genetic data, still unpublished in brazilian populations, which may offer subsidies for the characterization of the mutation dynamics and their patterns, on the origin and development of keratoconus. also will be evaluated the tomographic index as corneal curvature, thinnest point, corneal high order aberrations, posterior and anterior elevation, corneal densitometry, corneal volume. the idea is focused on that suspicious cornea that has the fellow eye with unequivocal keratoconus.

Eligibility criteria:
inclusion criteria: * patients diagnosed with keratoconus in clinical examination, topography and tomography * patients with clinical examination, topography, and tomography aspect of sound cornea in one eye, and the fellow eye diagnosed with keratoconus by clinical examination, topography, and tomography. patients diagnosed with keratoconus by clinical examination, topography, and tomography in both eyes (ou). * patients with some degree of ametropia that underwent to prk and lasik exclusion criteria: * history of eye trauma, glaucoma, dysfunctional tear syndrome, rosacea, neurotrophic keratopathy, systemic or topical use of immunosuppressive drugs, previous ocular surgeries.

Keywords: keratoconus,corneal dystrophies, corneal tomography, topography