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Corneal Hydrops
Corneal hydrops is an uncommon complication seen in people with advanced keratoconus or other corneal ectatic disorders, and is characterized by stromal edema due to leakage of aqueous humor through a tear in Descemet's membrane. Although a hydrops usually causes increased scarring of the cornea, occasionally it will benefit a patient by creating a flatter cone, aiding the fitting of contact lenses. Corneal transplantation is not usually indicated during corneal hydrops. Signs and symptoms The person experiences pain and a sudden severe clouding of vision, with the cornea taking on a translucent milky-white appearance known as a corneal hydrops. Diagnosis Patients are recommended to take a Sodium Chloride eye drop solution as well as a Dexamethasone solution for a period of 4-6 weeks, timeframes may vary depending on the severity of a patients condition. Once the medication cycle is complete and the cloud clears, scarring will be left on the cornea. Management The effect is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratoconus
Keratoconus (KC) is a disorder of the eye that results in progressive thinning of the cornea. This may result in blurry vision, double vision, nearsightedness, irregular astigmatism, and light sensitivity leading to poor quality-of-life. Usually both eyes are affected. In more severe cases a scarring or a circle may be seen within the cornea. While the cause is unknown, it is believed to occur due to a combination of genetic, environmental, and hormonal factors. Patients with a parent, sibling, or child who has keratoconus have 15 to 67 times higher risk in developing corneal ectasia compared to patients with no affected relatives. Proposed environmental factors include rubbing the eyes and allergies. The underlying mechanism involves changes of the cornea to a cone shape. Diagnosis is most often by topography. Topography measures the curvature of the cornea and creates a colored "map" of the cornea. Keratoconus causes very distinctive changes in the appearance of these ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corneal Ectatic Disorders
Corneal ectatic disorders or corneal ectasia are a group of uncommon, noninflammatory, eye disorders characterised by bilateral thinning of the central, paracentral, or peripheral cornea. Types * Keratoconus, a progressive, noninflammatory, bilateral, asymmetric disease, characterized by paraxial stromal thinning and weakening that leads to corneal surface distortion. * Keratoglobus, a rare noninflammatory corneal thinning disorder, characterised by generalised thinning and globular protrusion of the cornea. * Pellucid marginal degeneration, a bilateral, noninflammatory disorder, characterized by a peripheral band of thinning of the inferior cornea. *Posterior keratoconus, a rare condition, usually congenital, which causes a nonprogressive thinning of the inner surface of the cornea, while the curvature of the anterior surface remains normal. Usually only a single eye is affected. * Post-LASIK ectasia, a complication of LASIK eye surgery. * Terrien's marginal degeneration, a painless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Humor
The aqueous humour is a transparent water-like fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary body, a structure supporting the lens of the eyeball. It fills both the anterior and the posterior chambers of the eye, and is not to be confused with the vitreous humour, which is located in the space between the lens and the retina, also known as the posterior cavity or vitreous chamber. Blood cannot normally enter the eyeball. Structure Composition *Amino acids: transported by ciliary muscles *98% water *Electrolytes ( pH = 7.4 -one source gives 7.1) **Sodium = 142.09 **Potassium = 2.2 - 4.0 **Calcium = 1.8 **Magnesium = 1.1 **Chloride = 131.6 **HCO3- = 20.15 **Phosphate = 0.62 ** Osm = 304 *Ascorbic acid *Glutathione *Immunoglobulins Function *Maintains the intraocular pressure and inflates the globe of the eye. It is this hydrostatic pressure that keeps the eyeball in a roughly spherical shape and keeps the walls of the eyeball ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Descemet's Membrane
Descemet's membrane ( or the Descemet membrane) is the basement membrane that lies between the corneal proper substance, also called stroma, and the endothelial layer of the cornea. It is composed of different kinds of collagen (Type IV and VIII) than the stroma. The endothelial layer is located at the posterior of the cornea. Descemet's membrane, as the basement membrane for the endothelial layer, is secreted by the single layer of squamous epithelial cells that compose the endothelial layer of the cornea. Structure Its thickness ranges from 3 μm at birth to 8–10 μm in adults.Johnson DH, Bourne WM, Campbell RJ: The ultrastructure of Descemet's membrane. I. Changes with age in normal cornea. Arch Ophthalmol 100:1942, 1982 The corneal endothelium is a single layer of squamous cells covering the surface of the cornea that faces the anterior chamber. Clinical significance Significant damage to the membrane may require a corneal transplant. Damage caused by the hereditary co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corneal Hydrops (Elise A
Corneal hydrops is an uncommon complication seen in people with advanced keratoconus or other corneal ectatic disorders, and is characterized by stromal edema due to leakage of aqueous humor through a tear in Descemet's membrane. Although a hydrops usually causes increased scarring of the cornea, occasionally it will benefit a patient by creating a flatter cone, aiding the fitting of contact lenses. Corneal transplantation is not usually indicated during corneal hydrops. Signs and symptoms The person experiences pain and a sudden severe clouding of vision, with the cornea taking on a translucent milky-white appearance known as a corneal hydrops. Diagnosis Patients are recommended to take a sodium chloride eye drop solution as well as a dexamethasone solution for a period of 4-6 weeks, timeframes may vary depending on the severity of a patient's condition. Once the medication cycle is complete and the cloud clears, scarring will be left on the cornea. Management The effect is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dexamethasone
Dexamethasone is a glucocorticoid medication used to treat rheumatic problems, a number of skin diseases, severe allergies, asthma, chronic obstructive lung disease, croup, brain swelling, eye pain following eye surgery, superior vena cava syndrome (a complication of some forms of cancer), and along with antibiotics in tuberculosis. In adrenocortical insufficiency, it may be used in combination with a mineralocorticoid medication such as fludrocortisone. In preterm labor, it may be used to improve outcomes in the baby. It may be given by mouth, as an injection into a muscle, as an injection into a vein, as a topical cream or ointment for the skin or as a topical ophthalmic solution to the eye. The effects of dexamethasone are frequently seen within a day and last for about three days. The long-term use of dexamethasone may result in thrush, bone loss, cataracts, easy bruising, or muscle weakness. It is in pregnancy category C in the United States, meaning that it should ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmosis
Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of higher solute concentration), in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a selectively permeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do work. Osmotic pressure is defined as the external pressure required to be applied so that there is no net movement of solvent across the membrane. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity. Osmosis is a vital process in biological systems, as biological membranes are semiperm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saline (medicine)
Saline (also known as saline solution) is a mixture of sodium chloride (salt) and water. It has a number of uses in medicine including cleaning wounds, removal and storage of contact lenses, and help with dry eyes. By injection into a vein it is used to treat dehydration such as that from gastroenteritis and diabetic ketoacidosis. Large amounts may result in fluid overload, swelling, acidosis, and high blood sodium. In those with long-standing low blood sodium, excessive use may result in osmotic demyelination syndrome. Saline is in the crystalloid family of medications. It is most commonly used as a sterile 9 g of salt per litre (0.9%) solution, known as normal saline. Higher and lower concentrations may also occasionally be used. Saline is acidic, with a pH of 5.5 (due mainly to dissolved carbon dioxide). The medical use of saline began around 1831. It is on the World Health Organization's List of Essential Medicines. In 2020, sodium was the 274th most commonly p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-steroidal Anti-inflammatory
Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of use, but largely include an increased risk of gastrointestinal ulcers and bleeds, heart attack, and kidney disease. The term ''non-steroidal'', common from around 1960, distinguishes these drugs from corticosteroids, which during the 1950s had acquired a bad reputation due to overuse and side-effect problems after their initial introduction in 1948. NSAIDs work by inhibiting the activity of cyclooxygenase enzymes (the COX-1 and COX-2 isoenzymes). In cells, these enzymes are involved in the synthesis of key biological mediators, namely prostaglandins, which are involved in inflammation, and thromboxanes, which are involved in blood clotting. There are two general types of NSAIDs available: non-selective, and COX-2 selective. Most NSAID ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dua's Layer
Dua's layer, according to a 2013 paper by Harminder Singh Dua's group at the University of Nottingham, is a layer of the cornea that had not been detected previously. It is hypothetically thick, the fourth caudal layer, and located between the corneal stroma and Descemet's membrane. Despite its thinness, the layer is very strong and impervious to air. It is strong enough to withstand up to 2 bars (200 kPa) of pressure. While some scientists welcomed the announcement, other scientists cautioned that time was needed for other researchers to confirm the discovery and its significance. Others have met the claim "with incredulity". Study In a paper published in 2013, the existence of a new layer was suggested by Harminder Singh Dua ''et al.'' Dua's team from the University of Nottingham are conducting transplant-related research on donated eyes. Simulating corneal surgery, they injected tiny bubbles of air into the cornea. Descemet's membrane was surgically removed, causing the air bub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harminder Singh Dua
Professor Harminder Singh Dua (Punjabi language, Punjabi: ਹਰਮਿੰਦਰ ਸਿੰਘ ਦੁਆਹ, born in Jalandhar, Punjab, India, Punjab, India) is an British Indians, Indian-British medical doctor and researcher. He is the chair and professor of ophthalmology at University of Nottingham and is the head of the Division of Ophthalmology and Visual Sciences. Prior, he was associate professor at the Thomas Jefferson University, Philadelphia, USA when he was invited to chair in Nottingham in April 1994. He earlier did his Graduation in Medicine from Government Medical College and Hospital, Nagpur. Dua is also the co-editor in chief with Arun Singh of the ''British Journal of Ophthalmology''. He was president of EuCornea, the European society of Cornea and Ocular surface disease specialists. He is also president of the EVERf (European Association for Vision and Eye Research Foundation) and past president of the association itself. He was elected to the chair of Academia Oph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disorders Of Sclera And Cornea
Disorder may refer to randomness, non-order, or no intelligible pattern. Disorder may also refer to: Healthcare * Disorder (medicine), a functional abnormality or disturbance * Mental disorder or psychological disorder, a psychological pattern associated with distress or disability that occurs in an individual and is not a part of normal development or culture: :* Anxiety disorder, different forms of abnormal and pathological fear and anxiety :* Conversion disorder, neurological symptoms such as numbness, blindness, paralysis, or fits, where no neurological explanation is possible :* Obsessive–compulsive disorder, an anxiety disorder characterized by repetitive behaviors aimed at reducing anxiety :* Obsessive–compulsive personality disorder, obsession with perfection, rules, and organization :* Personality disorder, an enduring pattern of inner experience and behavior that deviates markedly from the expectations of the culture of the individual who exhibits it Law enforceme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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