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Astigmatic Keratotomy
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. The lens and cornea of an eye without astigmatism are nearly spherical, with only a single radius of curvature, and any refractive errors present can be corrected with simple glasses. In an eye with astigmatism, either the lens or the cornea is slightly egg-shaped, with higher curvature in one direction than the other. This gives distorted or blurred vision at any distance and requires corrective lenses that apply different optical powers at different rotational angles. Astigmatism can lead to symptoms that include eyestrain, headaches, and trouble driving at night. Astigmatism often is present at birth, but can change or develop later in life. If it occurs in early life and is left untreated, it may result in amblyopia. The cause of astigmatism is unclear, although it is believed to be partly related to genetic factors. The underlying mechanism involves an irregular cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophthalmology
Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medical degree, a doctor specialising in ophthalmology must pursue additional postgraduate residency training specific to that field. In the United States, following graduation from medical school, one must complete a four-year residency in ophthalmology to become an ophthalmologist. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. Ophthalmologists prescribe medications to treat ailments, such as eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists provide both primary and specialty eye care—medical and surgical. Most ophthalmologists participate in academic research on eye diseases at some point in their training and many inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (anatomy)
The lens, or crystalline lens, is a Transparency and translucency, transparent Biconvex lens, biconvex structure in most land vertebrate eyes. Relatively long, thin fiber cells make up the majority of the lens. These cells vary in architecture and are arranged in concentric layers. New layers of cells are recruited from a thin epithelium at the front of the lens, just below the basement membrane surrounding the lens. As a result the vertebrate lens grows throughout life. The surrounding lens membrane referred to as the lens capsule also grows in a systematic way, ensuring the lens maintains an optically suitable shape in concert with the underlying fiber cells. Thousands of suspensory ligaments are embedded into the capsule at its largest diameter which suspend the lens within the eye. Most of these lens structures are derived from the epithelium of the embryo before birth. Along with the cornea, aqueous humour, aqueous, and vitreous humours, the lens Refraction, refracts light, Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CLDN7
Claudin-7 is a protein that in humans is encoded by the ''CLDN7'' gene. It belongs to the group of claudin Claudins are a family of proteins which, along with occludin, are the most important components of the tight junctions ( zonulae occludentes). Tight junctions establish the paracellular barrier that controls the flow of molecules in the inter ...s. Claudins, such as CLDN7, are involved in the formation of tight junctions between epithelial cells. Tight junctions restrict lateral diffusion of lipids and membrane proteins, and thereby physically define the border between the apical and basolateral compartments of epithelial cells (Zheng et al., 2003). upplied by OMIMref name="entrez" /> References External links * Further reading * * * * * * * * * * * * * * * {{gene-17-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FIP1L1
Factor interacting with PAPOLA and CPSF1 (i.e, FIP1L1; also termed Pre-mRNA 3'-end-processing factor FIP1) is a protein that in humans is encoded by the ''FIP1L1'' gene (also known as Rhe, FIP1, and hFip1). A medically important aspect of the ''FIP1L1'' gene is its fusion with other genes to form fusion genes which cause clonal hypereosinophilia and leukemic diseases in humans. Gene The human ''FIP1L1'' gene is located on chromosome 4 at position q12 (4q12), contains 19 exons, and codes for a complete protein consisting of 594 amino acids. However, alternative splicing of its precursor mRNA results in multiple transcript variants encoding distinct FIP1L1 protein isoforms. The ''FIP1L1'' gene is found in a wide range of species, being designated as FIP1 in ''Saccharomyces cerevisiae'' (yeast) and fip1l1 in coho salmon as well as mice and numerous other mammalian species. In humans, an interstitial chromosomal deletion of about 800 kilobases at 4q12 deletes the ''CHIC2'' gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDGFRA
Platelet-derived growth factor receptor A, also termed CD140a, is a Receptor (biochemistry), receptor located on the surface of a wide range of cell types. The protein is encoded in the human by the ''PDGFRA'' gene. This receptor binds to certain isoforms of platelet-derived growth factors (PDGFs) and thereby becomes active in stimulating cell signaling pathways that elicit responses such as Cell growth, cellular growth and cellular differentiation, differentiation. The receptor is critical for the embryonic development of certain tissues and organs, and for their maintenance, particularly hematologic tissues, throughout life. Mutations in ''PDGFRA'', are associated with an array of clinically significant neoplasms, notably ones of the clonal hypereosinophilia class of malignancies, as well as gastrointestinal stromal tumors (GISTs). Overall structure This gene encodes a typical receptor tyrosine kinase, which is a transmembrane protein consisting of an extracellular ligand bind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome-wide Association Study
In genomics, a genome-wide association study (GWA study, or GWAS), is an observational study of a genome-wide set of Single-nucleotide polymorphism, genetic variants in different individuals to see if any variant is associated with a trait. GWA studies typically focus on associations between single-nucleotide polymorphisms (SNPs) and traits like major human diseases, but can equally be applied to any other genetic variants and any other organisms. When applied to human data, GWA studies compare the DNA of participants having varying phenotypes for a particular trait or disease. These participants may be people with a disease (cases) and similar people without the disease (controls), or they may be people with different phenotypes for a particular trait, for example blood pressure. This approach is known as phenotype-first, in which the participants are classified first by their clinical manifestation(s), as opposed to Genotype-first approach, genotype-first. Each person gives a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Migraine
Migraine (, ) is a complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea, and light and sound sensitivity. Other characterizing symptoms may include vomiting, cognitive dysfunction, allodynia, and dizziness. Exacerbation or worsening of headache symptoms during physical activity is another distinguishing feature. Up to one-third of people with migraine experience aura, a premonitory period of sensory disturbance widely accepted to be caused by cortical spreading depression at the onset of a migraine attack. Although primarily considered to be a headache disorder, migraine is highly heterogenous in its clinical presentation and is better thought of as a spectrum disease rather than a distinct clinical entity. Disease burden can range from episodic discrete attacks to chronic disease. Migraine is believed to be caused by a mixture of environmental and genetic factors that influe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asthenopia
Eye strain, also medically termed as asthenopia (), is a common eye condition characterized by non-specific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache, and occasional double vision. These symptoms tend to arise after long-term use of computers, staring at phone screens, digital devices, reading, or other activities that involve extended visual tasks. Various causes contribute to eye strain, including uncorrected vision problems, digital device usage, environmental factors, and underlying health conditions. When concentrating on a visually intense task, such as continuously focusing on a book or computer monitor, the ciliary muscles and the extraocular muscles are strained, also contributing to the symptoms. These symptoms are broadly classified into external (related to the ocular surface) and internal symptom factors (related to eye muscles). Treatment involves environmental modifications, visual aids, and taking periodic breaks. The e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squinting
Squinting is the action of looking at something with partially closed eyes. Squinting is most often practiced by people who suffer from refractive errors of the eye who either do not have or are not using their glasses. Squinting helps momentarily improve their eyesight by slightly changing the shape of the eye to make it rounder, which helps light properly reach the fovea. Squinting also decreases the amount of light entering the eye, making it easier to focus on what the observer is looking at by removing rays of light which enter the eye at an angle and would need to otherwise be focused by the observer's faulty lens and cornea. Pinhole glasses, which severely restrict the amount of light entering the cornea, have the same effect as squinting. It is a common belief that squinting worsens eyesight. However, according to Robert MacLaren, a professor of ophthalmology at the University of Oxford, this is nothing more than an old wives' tale: the only damage that can be caused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Vision
Diplopia is the simultaneous perception of two images of a single object that may be displaced in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often voluntary. However, when occurring involuntarily, it results from impaired function of the extraocular muscles, where both eyes are still functional, but they cannot turn to target the desired object. Problems with these muscles may be due to mechanical problems, disorders of the neuromuscular junction, disorders of the cranial nerves ( III, IV, and VI) that innervate the muscles, and occasionally disorders involving the supranuclear oculomotor pathways or ingestion of toxins. Diplopia can be one of the first signs of a systemic disease, particularly to a muscular or neurological process, and it may disrupt a person's balance, movement, or reading abilities. Causes Diplopia has a diverse range of ophthalmologic, infectious, autoimmune, neurological, and neoplastic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Young (scientist)
Thomas Young Fellow of the Royal Society, FRS (13 June 177310 May 1829) was a British polymath who made notable contributions to the fields of Visual perception, vision, light, solid mechanics, energy, physiology, language, harmony, musical harmony, and Egyptology. He was instrumental in the decipherment of Egyptian hieroglyphs, specifically the Rosetta Stone. Young has been described as "The Last Man Who Knew Everything". His work influenced that of William Herschel, Hermann von Helmholtz, James Clerk Maxwell, and Albert Einstein. Young is credited with establishing Christiaan Huygens' wave theory of light, in contrast to the corpuscular theory of Isaac Newton. Young's work was subsequently supported by the work of Augustin-Jean Fresnel. Personal life Young belonged to a Quaker family of Milverton, Somerset, where he was born in 1773, the eldest of ten children. By the age of fourteen, Young had learned Greek language, Greek, Latin, French language, French, Italian language, It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Surgery
Refractive surgery is an optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea ( keratomileusis), lens implantation or lens replacement. The most common methods today use excimer lasers to reshape the curvature of the cornea. Refractive eye surgeries are used to treat common vision disorders such as myopia, hyperopia, presbyopia and astigmatism. History The first theoretical work on the potential of refractive surgery was published in 1885 by Hjalmar August Schiøtz, an ophthalmologist from Norway. In 1930, the Japanese ophthalmologist Tsutomu Sato made the first attempts at performing this kind of surgery, hoping to correct the vision of military pilots. His approach was to make radial cuts in the cornea, correcting effects by up to 6 diopters. The procedure unfortunately produced a high rate of corneal degeneration, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
