Absorb: 1. To take something in, as through the skin or the intestine.
2. To react with radiation and reduce it in intensity, as with a dose of radiation or transmitted light.
See also: Absorbed dose; Absorption; Malabsorption; Reabsorption.
Allergy : A misguided reaction to foreign substances by the immune system , the body system of defense against foreign invaders, particularly pathogens (the agents of infection ). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens , dust mite, molds , danders , and certain foods. People prone to allergies are said to be allergic or atopic .
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Astigmatism: A common form of visual impairment in which part of an image is blurred, due to an irregularity in the curvature of the front surface of the eye, the cornea. The curve of the cornea is shaped more like an American football or a rugby ball rather than a normal spherical basketball. Light rays entering the eye there are not uniformly focused on the retina. Rays entering through the more-curved surface are focused before the rays coming through the less-curved surface. The light is focused clearly along one plane but is blurred along the other. The result is blurred vision at all distances. Only part of what you are looking at is in clear focus at any one time.
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Baby blues: A common temporary psychological state right after childbirth when a new mother may have sudden mood swings, feeling very happy, then very sad, cry for no apparent reason, feel impatient, unusually irritable, restless, anxious, lonely and sad. The baby blues may last only a few hours or as long as 1 to 2 weeks after delivery. The baby blues in this sense are less severe than a postpartum depression . The baby blues do not always require treatment from a health care provider. Often, joining a support group of new mothers or talking with other mothers helps.
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Cornea: The clear front window of the eye that transmits and focuses light into the eye.
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Corneal: Pertaining to the cornea, the clear front window of the eye that transmits and focuses light into the eye.
Dry eye: A deficiency of tears. The main symptom is usually a scratchy or sandy feeling as if something is in the eye. Other symptoms may include stinging or burning of the eye; episodes of excess tearing that follow periods of very dry sensation; a stringy discharge from the eye; and pain and redness of the eye. Sometimes people with dry eye experience heaviness of the eyelids or blurred, changing, or decreased vision, although loss of vision is uncommon.
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Eye: The organ of sight. The eye has a number of components. These components include but are not limited to the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid and vitreous.
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Eye color: The color of the iris. The genetics of eye color are complicated. Eye color is polygenic. It is determined by multiple genes. The eye color genes include EYCL1 (a green/blue eye color gene located on chromosome 19), EYCL2 (a brown eye color gene) and EYCL3 (a brown/blue eye color gene located on chromosome 15). There are clearly other genes that influence eye color. The once-held view that blue eye color is a simple recessive trait has been shown to be wrong. The genetics of eye color are so complex that almost any parent-child combination of eye colors can occur.
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Farsightedness: Medically termed hyperopia; the ability to see distant objects more clearly than close objects.
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Health: As officially defined by the World Health Organization, a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity.
Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
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Lens: The transparent structure inside the eye that focuses light rays onto the retina (the nerve layer that lines the back of the eye, senses light and creates impulses that go through the optic nerve to the brain). The lens was named after the lentil bean because it resembled it in shape and size.
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Mind: That which thinks, reasons, perceives, wills, and feels. The mind now appears in no way separate from the brain. In neuroscience, there is no duality between the mind and body. They are one.
Mute: A mute is a person who does not speak, either from an inability to speak or an unwillingness to speak. The term "mute" is specifically applied to a person who, due to profound congenital (or early) deafness, is unable to use articulate language and so is deaf-mute. A mute in speech is a letter that is silent and also an element of speech formed by a position of the mouth which stops the passage of the breath, such as the letters p, b, d, k, and t. The word "mute" comes from the Latin "mutus" meaning unable to speak.
Nearsightedness: The ability to see near objects more clearly than distant objects. Also called myopia.
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Optic: Having to do with vision.
Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life.
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Presbyopia: The loss of the eye's ability to change focus to see near objects. The reasons for this loss of the power of accommodation are not yet fully known. It is conventionally said to be due to the lens becoming less elastic with time.
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Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.
Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea.
Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash ."
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Viral infection: Infection caused by the presence of a virus in the body. Depending on the virus and the person's state of health, various viruses can infect almost any type of body tissue, from the brain to the skin. Viral infections cannot be treated with antibiotics; in fact, in some cases the use of antibiotics makes the infection worse. The vast majority of human viral infections can be effectively fought by the body's own immune system, with a little help in the form of proper diet, hydration, and rest. As for the rest, treatment depends on the type and location of the virus, and may include anti-viral or other drugs.
- Eye Care - Get information on eye care tips and eye health, disorders and treatment with OTC eye-care products, and when to see an ophthalmologist about an eye infection or condition.
- Blepharitis - Eyelid inflammation (blepharitis) may be caused by Staphylococcal infection, allergies or head lice. Blepharitis, in turn, may cause styes, pinkeye and chalazions. Learn more.
- Subconjunctival Hemorrhage - Learn what causes a subconjunctival hemorrhage, a burst blood vessel in the eye, and read about symptoms, signs, diagnosis, treatment and prevention. In newborn infants, a subconjunctival hemorrhage may be a result of the birthing process.
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