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Small Incision Lenticule Extraction
ReLEx Small incision lenticule extraction (SMILE), second generation of ReLEx Femtosecond lenticule extraction (FLEx), is a form of laser based refractive eye surgery developed by Carl Zeiss Meditec used to correct myopia, and cure astigmatism. Although similar to LASIK laser surgery, the intrastromal procedure is novel in that it uses a single femtosecond laser referenced to the corneal surface to cleave a thin lenticule from the corneal stroma for manual extraction and SMILE. It has been described as a painless procedure. For candidates to qualify for this treatment, they have their corneal stroma thickness checked to make sure that post operative thickness won't be too thin. The lenticule to be extracted is accurately cut to the correction prescription required by the patient using a photodisruption laser-tissue interaction. The method of extraction was via a LASIK-type flap in ReLEx FLEx, but in SMILE a flapless technique makes a small tunnel incision in the corneal periph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Surgery
Refractive eye surgery is 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, howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Zeiss Meditec
Carl Zeiss Meditec AG is a multinational medical technology company and subsidiary of Carl Zeiss AG. It manufactures tools for eye examinations and medical lasers as well as solutions for neurosurgery, dentistry, gynecology and oncology. Among its products are the most common tools used by ophthalmologists and optometrists. In October 2018, Carl Zeiss Meditec won FDA premarket approval for its ReLEx Smile laser system. Also in October 2018, Carl Zeiss Meditec announced the acquisition of Reno, Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...-based IanTech for an undisclosed sum. In September 2019, Carl Zeiss Meditec launched the CIRRUS 6000 at the European Society of Retina Specialists 2019 Congress. References External links * Manufacturing companies of Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myopia
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include headaches and eye strain. Severe near-sightedness is associated with an increased risk of retinal detachment, cataracts, and glaucoma. The underlying mechanism involves the length of the eyeball growing too long or less commonly the lens being too strong. It is a type of refractive error. Diagnosis is by eye examination. Tentative evidence indicates that the risk of near-sightedness can be decreased by having young children spend more time outside. This decrease in risk may be related to natural light exposure. Near-sightedness can be corrected with eyeglasses, contact lenses, or a refractive surgery. Eyeglasses are the easiest and safest method of correction. Contact lenses can provide a wider field of vision, but are associated with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astigmatism
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at night. Astigmatism often occurs at birth and 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; however, it is believed to be partly related to genetic factors. The underlying mechanism involves an irregular curvature of the cornea and protective reaction changes in the lens of the eye, called lens astigmatism, that has the same mechanism as spasm of accomodation. Diagnosis is by an eye examination called autorefractor keratometry (objective, allows to see lens and cornea components of astigmatism) and subjective refraction, but subjective methods are almost always inaccurate, if lens astigmatism is not fully removed first with a week of e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LASIK
LASIK or Lasik (''laser-assisted in situ keratomileusis''), commonly referred to as laser eye surgery or laser vision correction, is a type of refractive surgery for the correction of myopia, hyperopia, and an actual cure for astigmatism, since it is in the cornea. LASIK surgery is performed by an ophthalmologist who uses a laser or microkeratome to reshape the eye's cornea in order to improve visual acuity. For most people, LASIK provides a long-lasting alternative to eyeglasses or contact lenses. LASIK is very similar to another surgical corrective procedure, photorefractive keratectomy (PRK), and LASEK. All represent advances over radial keratotomy in the surgical treatment of refractive errors of vision. For patients with moderate to high myopia or thin corneas which cannot be treated with LASIK and PRK, the phakic intraocular lens is an alternative. As of 2018, roughly 9.5 million Americans have had LASIK and, globally, between 1991 and 2016, more than 40 million proced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroma Of Cornea
The stroma of the cornea (or substantia propria) is a fibrous, tough, unyielding, perfectly transparent and the thickest layer of the cornea of the eye. It is between Bowman's membrane anteriorly, and Descemet's membrane posteriorly. At its centre, human corneal stroma is composed of about 200 flattened ''lamellæ'' (layers of collagen fibrils), superimposed one on another. They are each about 1.5-2.5 μm in thickness. The anterior lamellæ interweave more than posterior lamellæ. The fibrils of each lamella are parallel with one another, but at different angles to those of adjacent lamellæ. The lamellæ are produced by keratocytes (corneal connective tissue cells), which occupy about 10% of the substantia propria. Apart from the cells, the major non-aqueous constituents of the stroma are collagen fibrils and proteoglycans. The collagen fibrils are made of a mixture of type I and type V collagens. These molecules are tilted by about 15 degrees to the fibril axis, and because of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lenticular Lens
A lenticular lens is an array of lenses, designed so that when viewed from slightly different angles, different parts of the image underneath are shown. The most common example is the lenses used in lenticular printing, where the technology is used to give an illusion of depth, or to make images that appear to change or move as the image is viewed from different angles. Applications Lenticular printing Lenticular printing is a multi-step process consisting of creating a lenticular image from at least two existing images, and combining it with a lenticular lens. This process can be used to create various frames of animation (for a motion effect), offsetting the various layers at different increments (for a 3D effect), or simply to show a set of alternate images which may appear to transform into each other. Corrective lenses Lenticular lenses are sometimes used as corrective lenses for improving vision. A bifocal lens could be considered a simple example. Lenticular eyeglass lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photodisruption
Photodisruption is a form of minimally invasive surgery used in ophthalmology, utilizing infrared Nd:YAG lasers to form plasma ("lightning bolt"), which then causes acoustic shock waves ("thunderclap") which then in turn affects tissue. The tissue ruptures as a result of the vapor bubble produced by the laser; the temperature required to produce this effect is between 100 and 305 °C. Because the infrared laser is invisible to the surgeon's eye, typically a companion HeNe laser is used in conjunction. However, the eye lens acts as a prism, so the infrared light bends at a shallower angle than the red light, causing chromatic aberration. This means the area highlighted by the HeNe laser is not precisely the area being affected Nd:YAG laser, and therefore some surgical lasers have an added adjustment to compensate. The first successful use of photodisruption was in 1972, on a case of trabecular meshwork. Photodisruption came to wide use in the early 1980s for the treatment of e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowman's Membrane
The Bowman layer (Bowman's membrane, anterior limiting lamina, anterior elastic lamina) is a smooth, acellular, nonregenerating layer, located between the superficial epithelium and the stroma in the cornea of the eye. It is composed of strong, randomly oriented collagen fibrils in which the smooth anterior surface faces the epithelial basement membrane and the posterior surface merges with the collagen lamellae of the corneal stroma proper. In adult humans, Bowman layer is 8-12 μm thick. With ageing, this layer becomes thinner. The function of the Bowman layer remains unclear and appears to have no critical function in corneal physiology. Recently, it is postulated that the layer may act as a physical barrier to protect the subepithelial nerve plexus and thereby hastens epithelial innervation and sensory recovery. Moreover, it may also serve as a barrier that prevents direct traumatic contact with the corneal stroma and hence it is highly involved in stromal wound healing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Far-sightedness
Far-sightedness, also known as long-sightedness, hypermetropia, or hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred. This blurred effect is due to incoming light being focused behind, instead of on, the retina wall due to insufficient accommodation by the lens. Minor hypermetropia in young patients is usually corrected by their accommodation, without any defects in vision. But, due to this accommodative effort for distant vision, people may complain of eye strain during prolonged reading. Some hypermetropes can see clear at distance, but near vision may be blurred due to insufficient accommodation. For this reason, this defect is referred as far-sightedness. If the hypermetropia is high, there will be defective vision for both distance and near. People may also experience accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus. Newborns are almost invariably hypermetropic, but it gradually decreas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Femtosecond Laser
Mode locking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds (10−12 s) or femtoseconds (10−15 s). A laser operated in this way is sometimes referred to as a femtosecond laser, for example, in modern refractive surgery. The basis of the technique is to induce a fixed phase relationship between the longitudinal modes of the laser's resonant cavity. Constructive interference between these modes can cause the laser light to be produced as a train of pulses. The laser is then said to be "phase-locked" or "mode-locked". Laser cavity modes Although laser light is perhaps the purest form of light, it is not of a single, pure frequency or wavelength. All lasers produce light over some natural bandwidth or range of frequencies. A laser's bandwidth of operation is determined primarily by the gain medium from which the laser is constructed, and the range of frequencies over which a lase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibronectin
Fibronectin is a high- molecular weight (~500-~600 kDa) glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins. Fibronectin also binds to other extracellular matrix proteins such as collagen, fibrin, and heparan sulfate proteoglycans (e.g. syndecans). Fibronectin exists as a protein dimer, consisting of two nearly identical monomers linked by a pair of disulfide bonds. The fibronectin protein is produced from a single gene, but alternative splicing of its pre-mRNA leads to the creation of several isoforms. Two types of fibronectin are present in vertebrates: * soluble plasma fibronectin (formerly called "cold-insoluble globulin", or CIg) is a major protein component of blood plasma (300 μg/ml) and is produced in the liver by hepatocytes. * insoluble cellular fibronectin is a major component of the extracellular matrix. It is secreted by various cells, primarily fibroblasts, as a soluble protein dimer and is then ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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