|
Corneal Ulcer
Corneal ulcer is an inflammatory or, more seriously, infective condition of the cornea involving disruption of its epithelial layer with involvement of the corneal Stroma of cornea, stroma. It is a common condition in humans particularly in the tropics and the agrarian societies. In developing countries, children afflicted by Vitamin A deficiency are at high risk for corneal ulcer and may become blind in both eyes, which may persist lifelong. In ophthalmology, a corneal ulcer usually refers to having an infectious cause while the term corneal abrasion refers more to physical abrasions. Types Superficial and deep corneal ulcers Corneal ulcers are a common human eye disease. They are caused by trauma, particularly with vegetable matter, as well as chemical injury, contact lenses and infections. Other eye conditions can cause corneal ulcers, such as entropion, distichiasis, corneal dystrophy, and keratoconjunctivitis sicca (dry eye). Many micro-organisms cause infective corneal ulc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Keratitis
Keratitis is a condition in which the eye's cornea, the clear dome on the front surface of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves any of the following symptoms: pain, impaired eyesight, photophobia (light sensitivity), red eye and a 'gritty' sensation. Classification (by chronicity) Acute * Acute epithelial keratitis * Nummular keratitis * Interstitial keratitis * Disciform keratitis Chronic * Neurotrophic keratitis * Mucous plaque keratitis Classification (infective) Viral * Herpes simplex keratitis (dendritic keratitis). Viral infection of the cornea is often caused by the herpes simplex virus (HSV) which frequently leaves what is called a 'dendritic ulcer'. * Herpes zoster keratitis, associated with herpes zoster ophthalmicus, which is a form of shingles. Bacterial * Bacterial keratitis. Bacterial infection of the cornea can follow from an injury or from wearing contact lenses. The bacteria involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspergillus
'''' () is a genus consisting of several hundred mold species found in various climates worldwide. ''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Micheli was reminded of the shape of an ''aspergillum'' (holy water sprinkler), from Latin ''spargere'' (to sprinkle), and named the genus accordingly. Aspergillum is an asexual spore-forming structure common to all ''Aspergillus'' species; around one-third of species are also known to have a sexual stage. While some species of ''Aspergillus'' are known to cause fungal infections, others are of commercial importance. Taxonomy Species ''Aspergillus'' consists of 837 species of fungi. Growth and distribution ''Aspergillus'' is defined as a group of conidial fungi—that is, fungi in an asexual state. Some of them, however, are known to have a teleomorph (sexual state) in the Ascomycota. With DNA evidence, all members of the genus '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corneal Perforation
Corneal perforation is an anomaly in the cornea resulting from damage to the corneal surface. A corneal perforation means that the cornea has been penetrated, thus leaving the cornea damaged. The cornea is a clear part of the eye which controls and focuses the entry of light into the eye. Damage to the cornea due to corneal perforation can cause decreased visual acuity. Signs and symptoms Corneal perforation may cause difficulty in seeing and persistent eye pain. Physical examination may reveal discoloration of the cornea. Causes Perforation of the cornea may occur due to diseases of the cornea, injury during eye surgery, or infection of the eye, which may occur after surgery or procedures. Pellucid marginal degeneration may cause corneal thinning, leading to perforation. Diagnosis Corneal perforation can be diagnosed by using the Seidel test. Any aqueous leakage is revealed during the Seidel test confirms corneal perforation. A fluorescence strip is wiped over the wound. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydia Trachomatis
''Chlamydia trachomatis'' (), commonly known as chlamydia, is a bacterium that causes chlamydia, which can manifest in various ways, including: trachoma, lymphogranuloma venereum, nongonococcal urethritis, cervicitis, salpingitis, pelvic inflammatory disease. ''C. trachomatis'' is the most common infectious cause of blindness and the most common sexually transmitted bacterium. Different types of ''C. trachomatis'' cause different diseases. The most common strains cause disease in the genital tract, while other strains cause disease in the eye or lymph nodes. Like other ''Chlamydia'' species, the ''C. trachomatis'' life cycle consists of two morphologically distinct life stages: elementary bodies and reticulate bodies. Elementary bodies are spore-like and infectious, whereas reticulate bodies are in the replicative stage and are seen only within host cells. Description ''Chlamydia trachomatis'' is a gram-negative bacterium that can replicate only within a host cell. Over the cour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthamoeba Keratitis
''Acanthamoeba'' keratitis (AK) is a rare disease in which amoebae of the genus ''Acanthamoeba'' invade the clear portion of the front (cornea) of the eye. It affects roughly 100 people in the United States each year. ''Acanthamoeba'' are protozoa found nearly ubiquitously in soil and water and can cause infections of the skin, eyes, and central nervous system. Infection of the cornea by ''Acanthamoeba'' is difficult to treat with conventional medications, and AK may cause permanent visual impairment or blindness, due to damage to the cornea or through damage to other structures important to vision. Recently, AK has been recognized as an orphan disease and a funded project, orphan diseases ''Acanthamoeba'' keratitis (ODAK), has tested the effects of a diverse range drugs and biocides on AK. Pathogenesis In the United States, ''Acanthamoeba'' keratitis is nearly always associated with soft contact lens use. ''Acanthamoeba'' spp. is most commonly introduced to the eye by contact l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herpes Of The Eye
Herpetic simplex keratitis is a form of keratitis caused by recurrent herpes simplex virus (HSV) infection in the cornea. It begins with infection of epithelial cells on the surface of the eye and retrograde infection of nerves serving the cornea. Primary infection typically presents as swelling of the conjunctiva and eyelids (blepharoconjunctivitis), accompanied by small white itchy lesions on the corneal surface. The effect of the lesions varies, from minor damage to the epithelium ( superficial punctate keratitis), to more serious consequences such as the formation of dendritic ulcers. Infection is unilateral, affecting one eye at a time. Additional symptoms include dull pain deep inside the eye, mild to acute dryness, and sinusitis. Most primary infections resolve spontaneously in a few weeks. Healing can be aided by the use of oral and topical antivirals. Subsequent recurrences may be more severe, with infected epithelial cells showing larger dendritic ulceration, and lesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus
Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the common cold (which is also caused by other viruses, predominantly rhinoviruses), while more lethal varieties can cause SARS, MERS and COVID-19, which is causing the ongoing pandemic. In cows and pigs they cause diarrhea, while in mice they cause hepatitis and encephalomyelitis. Coronaviruses constitute the subfamily ''Orthocoronavirinae'', in the family ''Coronaviridae'', order '' Nidovirales'' and realm '' Riboviria''. They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 26 to 32 kilobases, one of the largest among RNA viruses. They have characteristic club-shaped spikes that project from their surface, which in electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenovirus
Adenoviruses (members of the family ''Adenoviridae'') are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from their initial isolation from human adenoids in 1953. They have a broad range of vertebrate hosts; in humans, more than 50 distinct adenoviral serotypes have been found to cause a wide range of illnesses, from mild respiratory infections in young children (known as the common cold) to life-threatening multi-organ disease in people with a weakened immune system. Virology Classification This family contains the following genera: * '' Atadenovirus'' * '' Aviadenovirus'' * '' Ichtadenovirus'' * '' Mastadenovirus'' (including all human adenoviruses) * '' Siadenovirus'' * '' Testadenovirus'' Diversity In humans, currently there are 88 human adenoviruses (HAdVs) in seven species (Human adenovirus A to G): * A: 12, 18, 31 * B: 3, 7, 11, 14, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herpes Zoster
Shingles, also known as zoster or herpes zoster, is a viral disease characterized by a painful skin rash with blisters in a localized area. Typically the rash occurs in a single, wide mark either on the left or right side of the body or face. Two to four days before the rash occurs there may be tingling or local pain in the area. Otherwise, there are typically few symptoms though some people may have fever or headache, or feel tired. The rash usually heals within two to four weeks; however, some people develop ongoing nerve pain which can last for months or years, a condition called postherpetic neuralgia (PHN). In those with poor immune function the rash may occur widely. If the rash involves the eye, vision loss may occur. Shingles is caused by the varicella zoster virus (VZV) that also causes chickenpox. In the case of chickenpox, also called varicella, the initial infection with the virus typically occurs during childhood or adolescence. Once the chickenpox has resolved, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herpes Simplex
Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold sores or fever blisters or may just cause a sore throat. Genital herpes, often simply known as herpes, involves the genitalia. It may have minimal symptoms or form blisters that break open and result in small ulcers. These typically heal over two to four weeks. Tingling or shooting pains may occur before the blisters appear. Herpes cycles between periods of active disease followed by periods without symptoms. The first episode is often more severe and may be associated with fever, muscle pains, swollen lymph nodes and headaches. Over time, episodes of active disease decrease in frequency and severity. Herpetic whitlow typically involves the fingers or thumb. Herpes simplex keratitis involves the eye. Herpesviral encephalitis involves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypopyon
Hypopyon is a medical condition involving inflammatory cells in the anterior chamber of the eye. It is an exudate rich in white blood cells, seen in the anterior chamber, usually accompanied by redness of the conjunctiva and the underlying episclera. It is a sign of inflammation of the anterior uvea and iris, i.e. iritis, which is a form of anterior uveitis. The exudate settles at the dependent aspect of the eye due to gravity. It can be sterile (in bacterial corneal ulcer) or not sterile (fungal corneal ulcer). Differential diagnosis Hypopyon can be present in a corneal ulcer. It can occur as a result of Behçet's disease, endophthalmitis, panuveitis/panophthalmitis, or adverse reactions to some drugs (such as rifabutin). Hypopyon is also known as ''sterile pus'' because it occurs due to the release of toxins and not by the actual invasion of pathogens. The toxins secreted by the pathogens mediate the outpouring of leukocytes that settle in the anterior chamber of the eye. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mucor
''Mucor'' is a microbial genus of approximately 40 species of molds in the family Mucoraceae. Species are commonly found in soil, digestive systems, plant surfaces, some cheeses like Tomme de Savoie, rotten vegetable matter and iron oxide residue in the biosorption process. Description Colonies of this fungal genus are typically white to beige or grey and fast-growing. Colonies on culture medium may grow to several centimeters in height. Older colonies become grey to brown in color due to the development of spores. The species 'Mucor' belongs to the microbial kingdom: Fungi. ''Mucor'' spores or sporangiospores can be simple or branched and form apical, globular sporangia that are supported and elevated by a column-shaped columella. ''Mucor'' species can be differentiated from molds of the genera ''Absidia'', ''Rhizomucor'', and ''Rhizopus'' by the shape and insertion of the columella, and the lack of stolons and rhizoids. Some ''Mucor'' species produce chlamydospores. They fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
