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Cataract Surgery
Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye (also called "crystalline lens") that has developed an opacification, which is referred to as a cataract, and its replacement with an intraocular lens. Metabolic changes of the crystalline lens fibers over time lead to the development of the cataract, causing impairment or loss of vision. Some infants are born with congenital cataracts, and certain environmental factors may also lead to cataract formation. Early symptoms may include strong glare from lights and small light sources at night, and reduced acuity at low light levels. During cataract surgery, a patient's cloudy natural cataract lens is removed, either by emulsification in place or by cutting it out. An artificial intraocular lens (IOL) is implanted in its place. Cataract surgery is generally performed by an ophthalmologist in an ambulatory setting at a surgical center or hospital rather than an inpatient settin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophthalmology
Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye 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. This may include a one-year integrated internship that involves more general medical training in other fields such as internal medicine or general surgery. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. Ophthalmologists prescribe medications to treat 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 include research as par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacoemulsification
Phacoemulsification is a modern cataract surgery method in which the eye's internal lens is emulsified with an ultrasonic handpiece and aspirated from the eye. Aspirated fluids are replaced with irrigation of balanced salt solution to maintain the anterior chamber. Etymology The term originated from phaco- (Greek ''phako-'', comb. form of ''phakós'', lentil; see lens) + emulsification. Preparation and precautions Proper anesthesia is essential for ocular surgery. Topical anesthesia is most commonly employed, typically by the instillation of a local anesthetic such as tetracaine or lidocaine. Alternatively, lidocaine and/or longer-acting bupivacaine anesthetic may be injected into the area surrounding (peribulbar block) or behind (retrobulbar block) the eye muscle cone to more fully immobilize the extraocular muscles and minimize pain sensation. A facial nerve block using lidocaine and bupivacaine may occasionally be performed to reduce lid squeezing. General anesthesia is re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subluxation
A subluxation is an incomplete or partial dislocation of a joint or organ. According to the World Health Organization (WHO), a subluxation is a "significant structural displacement", and is therefore always visible on static imaging studies, such as X-rays. In contrast, the chiropractic belief of "vertebral subluxation" may or may not involve a significant displacement or even pain or clear dysfunction.WHO guidelines on basic training and safety in chiropractic p. 4, including footnote. Joints [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryosurgery
Cryosurgery is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. The term comes from the Greek words cryo (κρύο) ("icy cold") and surgery (''cheirourgiki'' – χειρουργική) meaning "hand work" or "handiwork". Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions. Uses Warts, moles, skin tags, solar keratoses, molluscum, Morton's neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treated with cryosurgery, including liver cancer, prostate cancer, lung cancer, oral cancers, cervical disorders and, more commonly in the past, hemorrhoids. Soft tissue conditions such as plantar fasciitis (jogger's heel) and fibroma (benign excrescence of connective tissue) can be treated with cryosurgery. Cryosurgery works by taking advantage of the des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Nitrogen
Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is widely used as a coolant. Physical properties The diatomic character of the N2 molecule is retained after liquefaction. The weak van der Waals interaction between the N2 molecules results in little interatomic interaction, manifested in its very low boiling point. The temperature of liquid nitrogen can readily be reduced to its freezing point by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of nitrogen gas bubbles. This effect, known as the Leidenfrost effect, occurs when any liquid comes in contact with a surface which is significantly hotter than its boil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryoextraction (medicine)
In ophthalmology, cryoextraction is a form of intracapsular cataract extraction in which a cryoextractor, a special type of cryoprobe Cryosurgery is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. The term comes from the Greek words cryo (κρύο) ("icy cold") and surgery (''cheirourgiki'' – χ� ..., is used to freeze the crystalline lens and pull it intact from the eye. Dr. Charles Kelman is credited with pioneering this surgical method in 1962. It can also be used in the treatment of orbital tumors. References Eye surgery {{treatment-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mode-locking
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (morphology)
In biological morphology and anatomy, a sulcus (pl. ''sulci'') is a furrow or fissure (Latin ''fissura'', plural ''fissurae''). It may be a groove, natural division, deep furrow, elongated cleft, or tear in the surface of a limb or an organ, most notably on the surface of the brain, but also in the lungs, certain muscles (including the heart), as well as in bones, and elsewhere. Many sulci are the product of a surface fold or junction, such as in the gums, where they fold around the neck of the tooth. In invertebrate zoology, a sulcus is a fold, groove, or boundary, especially at the edges of sclerites or between segments. In pollen a grain that is grooved by a sulcus is termed sulcate. Examples in anatomy Liver *Ligamentum teres hepatis fissure * Ligamentum venosum fissure * Portal fissure, found in the under-surface of the liver * Transverse fissure of liver, found in the lower surface of the liver * Umbilical fissure, found in front of the liver Lung *Azygos fissure, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating Microscope
An operating microscope or surgical microscope is an optical microscope specifically designed to be used in a surgical setting, typically to perform microsurgery. Design features of an operating microscope are: magnification typically in the range from 4x-40x, components that are easy to sterilize or disinfect in order to ensure cross-infection control. There is often a prism that allows splitting of the light beam in order that assistants may also visualize the procedure or to allow photography or video to be taken of the operating field. Typically an operating microscope might cost several thousand dollars for a basic model, more advanced models may be much more expensive. Additionally specialized microsurgical instruments may be required to make full use of the improved vision the microscope affords. It can take time to master use of an operating microscope. Fields of medicine that make significant use of the operating microscope include plastic surgery, dentistry (espec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreous Body
The vitreous body (''vitreous'' meaning "glass-like"; , ) is the clear gel that fills the space between the lens and the retina of the eyeball (the vitreous chamber) in humans and other vertebrates. It is often referred to as the vitreous humor (also spelled humour, from Latin meaning liquid) or simply "the vitreous". Vitreous fluid or "liquid vitreous" is the liquid component of the vitreous gel, found after a vitreous detachment. It is not to be confused with the aqueous humor, the other fluid in the eye that is found between the cornea and lens. Structure The vitreous humor is a transparent, colorless, gelatinous mass that fills the space in the eye between the lens and the retina. It is surrounded by a layer of collagen called the vitreous membrane (or hyaloid membrane or vitreous cortex) separating it from the rest of the eye. It makes up four-fifths of the volume of the eyeball. The vitreous humour is fluid-like near the centre, and gel-like near the edges. The vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. The cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its focus is fixed. Accommodation (the refocusing of light to better view near objects) is accomplished by changing the geometry of the lens. Medical terms related to the cornea often start with the prefix "'' kerat-''" from the Greek word κέρας, ''horn''. Structure The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the healthy cornea does not have or need blood ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
