Lens-Particle Glaucoma Glossary of Medical Terms

Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
See the entire definition of Acute

Angle-closure glaucoma: This condition can be acute or chronic. It consists of increased pressure in the front chamber (anterior chamber) of the eye due to sudden (acute) or slowly progressive (chronic) blockage of the normal circulation of fluid within the eye. The block takes place at the angle of the anterior chamber formed by its junction of the cornea with the iris. This angle can be seen by simply looking at someone's eye from the side. Angle-closure glaucoma tends to affect people born with a narrow angle. People of Asian and Eskimo ancestry are at higher risk of developing it. Age and family history are risk factors. It occurs in older women more often than others. When the pupil of the eye is wide open (dilated), the iris is retracted and thickened and it block the canal of Schlemm, a key component of the drainage pathway for fluid within the eye. Blocking the drainage canal of Schlemm sends the pressure within the eye up. With acute angle-closure glaucoma, there is an abrupt increase in intraocular pressure (IOP) due to the buildup of aqueous (fluid) in the eye. The high pressure can damage the optic nerve (the nerve to the eye) and lead to blindness. The elevated pressure is best detected before the appearance of symptoms. That is why when the eyes are dilated in a doctor's office for a refraction, eye pressures are checked. When symptoms of acute angle glaucoma do develop, they include severe eye and facial pain, nausea and vomiting, decreased vision, blurred vision and seeing haloes around light. The eye in a far advanced case of angle closure glaucoma appears red with a steamy (clouded) cornea and a fixed (nonreactive) dilated pupil. Acute angle-closure glaucoma is an emergency because optic nerve damage and vision loss can occur within hours of the onset of the problem. Administering medications to lower the pressure within the eye is done first. In the past, a piece of the iris was then surgically removed in a procedure called an iridectomy to make a hole in the iris and create a channel (other than the canal of Sclemm) to permit the free flow of fluid. Today, a comparable procedure can be done by laser to burn a small hole in the iris to keep the intraocular pressure within normal limits. This condition can be chronic (progressing slowly or occurring persistently) or acute (occurring suddenly). Chronic angle-closure glaucoma, like the more common type of glaucoma (open-angle glaucoma), may cause vision damage without symptoms.
See the entire definition of Angle-closure glaucoma

Anterior: The front, as opposed to the posterior. The anterior surface of the heart is toward the breast bone (the sternum).
See the entire definition of Anterior

Anterior chamber: The space in the eye that is behind the cornea and in front of the iris.
See the entire definition of Anterior chamber

Aqueous humor: In medicine, humor refers to a fluid (or semifluid) substance. Thus, the aqueous humor is the fluid normally present in the front and rear chambers of the eye. It is a clear, watery fluid that flows between and nourishes the lens and the cornea; it is secreted by the ciliary processes.
See the entire definition of Aqueous humor

Blindness: Loss of useful sight. Blindness can be temporary or permanent. Damage to any portion of the eye, the optic nerve, or the area of the brain responsible for vision can lead to blindness. There are numerous (actually, innumerable) causes of blindness. The current politically correct terms for blindness include visually handicapped and visually challenged.
See the entire definition of Blindness

Capsule: Capsule has many meanings in medicine including the following:

1. In medicine, a membranous structure that envelops an organ, a joint, tumor, or any other part of the body. It is usually made up of dense collagen-containing connective tissue.
2. In pharmacy, a solid dosage form in which the drug is enclosed in a hard or soft soluble container, usually of a form of gelatin.
3. In microbiology, a coat around a microbe, such as a bacterium or fungus.

See the entire definition of Capsule

Cataract: A clouding of the lens of the eye. The normally clear aspirin-sized lens of the eye starts to become cloudy. The result is much like smearing grease over the lens of a camera. It impairs normal vision.

See the entire definition of Cataract

Cataract surgery: Removal of the clouded lens (the cataract ) in its entirety by surgery, usually followed by replacement of the lens with an intraocular lens (IOL) made of plastic, silicone, acrylic or other material. The operation typically takes about an hour, is done under local anesthetic only, and does not require hospitalization.

See the entire definition of Cataract surgery

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
See the entire definition of Chronic

Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
See the entire definition of Complication

Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
See the entire definition of Congenital

Cornea: The clear front window of the eye that transmits and focuses light into the eye.
See the entire definition of Cornea

Cortex: The outer portion of an organ.
See the entire definition of Cortex

Diagnosis: 1 The nature of a disease ; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies . 3 The identification of any problem. The diagnosis was a plugged IV.
See the entire definition of Diagnosis

Dilation: The process of enlargement, stretching, or expansion. The word "dilatation" means the same thing. Both come from the Latin "dilatare" meaning "to enlarge or expand."
See the entire definition of Dilation

Drain: A device for removing fluid from a cavity or wound. A drain is typically a tube or wick. As a verb, to allow fluid to be released from a confined area.
See the entire definition of Drain

Exacerbate: To make worse. For example, smoking may exacerbate systemic lupus erythematosus .
See the entire definition of Exacerbate

Glaucoma : A common eye condition in which the fluid pressure inside the eyes rises because of slowed fluid drainage from the eye. If untreated, it may damage the optic nerve and other parts of the eye, causing the loss of vision or even blindness.
See the entire definition of Glaucoma

Hospital: It may seem unnecessary to define a "hospital" since everyone knows the nature of a hospital. A hospital began as a charitable institution for the needy, aged, infirm, or young.
See the entire definition of Hospital

Humor: In medicine, humor refers to a fluid (or semifluid) substance. Thus, the aqueous humor is the fluid normally present in the front and rear chambers of the eye. The humors ran through an ancient theory that held that health came from balance between the bodily liquids. These liquids were termed humors. Disease arose when there was imbalance between these humors.
See the entire definition of Humor

Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
See the entire definition of Inflammation

Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury . The injury may be accidental or deliberate, as with a needlestick injury . The term "injury" may be synonymous (depending on the context) with a wound or with trauma .
See the entire definition of Injury

Intervention: The act of intervening, interfering or interceding with the intent of modifying the outcome. In medicine, an intervention is usually undertaken to help treat or cure a condition. For example, early intervention may help children with autism to speak. "Acupuncture as a therapeutic intervention is widely practiced in the United States," according to the National Institutes of Health. From the Latin intervenire, to come between.
See the entire definition of Intervention

Intraocular: In the eye. The intraocular pressure is the pressure within the eye.
See the entire definition of Intraocular

Intraocular pressure: The pressure created by the continual renewal of fluids within the eye. The intraocular pressure is increased in glaucoma .
See the entire definition of Intraocular pressure

Iris: The iris is the circular, colored curtain of the eye. Its opening forms the pupil. The iris helps regulate the amount of light that enters the eye.
See the entire definition of Iris

Laser: A powerful beam of light that can produce intense heat when focused at close range. Lasers are used in medicine in microsurgery, cauterization, for diagnostic purposes, etc. For example, lasers are employed in microsurgery to cut tissue and remove tissue.
See the entire definition of Laser

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.
See the entire definition of Lens

Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")
See the entire definition of Medication

Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.
See the entire definition of Microscope

Microscopic: So small it cannot be seen without the aid of microscope. As opposed to macroscopic (large enough to be seen with naked eye). A tiny tumor is microscopic while a big tumor is macroscopic.
See the entire definition of Microscopic

Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system .
See the entire definition of Nerve

Nucleus: 1) In cell biology, the structure that houses the chromosomes. 2) In neuroanatomy, a group of nerve cells.
See the entire definition of Nucleus

Obstruction: Blockage of a passageway. See, for example: Airway obstruction ; Intestinal obstruction .
See the entire definition of Obstruction

Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis . There is always an onset to a disease but never to the return to good health. The default setting is good health.
See the entire definition of Onset

Open-angle glaucoma : Glaucoma in which the aqueous (fluid) that flows through the pupil into the anterior (front) chamber of the eye cannot get through a filtration system called the trabecular meshwork into the drainage canals, causing pressure to build up within the eye which can damage the optic nerve and impair vision.
See the entire definition of Open-angle glaucoma

Ophthalmologist: An eye doctor. A physician practicing ophthalmology. An ophthalmologist is an M.D.
See the entire definition of Ophthalmologist

Ophthalmology: The art and science of eye medicine.
See the entire definition of Ophthalmology

Ophthalmoscopy: Examination of the interior of the eye , including the lens , retina and optic nerve , by indirect or direct ophthalmoscopy.
See the entire definition of Ophthalmoscopy

Optic: Having to do with vision.
See the entire definition of Optic

Optic nerve: The optic nerve connects the eye to the brain. The optic nerve carries the impulses formed by the retina, the nerve layer that lines the back of the eye and senses light and creates impulses. These impulses are dispatched through the optic nerve to the brain, which interprets them as images. Using an ophthalmoscope, the head of the optic nerve can be easily seen. It can be viewed as the only visible part of the brain (or extension of it).
See the entire definition of Optic nerve

Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
See the entire definition of Pain

Peripheral: Situated away from the center, as opposed to centrally located.
See the entire definition of Peripheral

Peripheral vision: Side vision. The ability to see objects and movement outside of the direct line of vision. Peripheral vision is the work of the rods, nerve cells located largely outside the macula (the center) of the retina. The rods are also responsible for night vision and low-light vision but are insensitive to color. As opposed to central vision.
See the entire definition of Peripheral vision

Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
See the entire definition of Pharmacy

Prevalence: The proportion of individuals in a population having a disease. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time.
See the entire definition of Prevalence

Prognosis: 1. The expected course of a disease .
2. The patient's chance of recovery.
The prognosis predicts the outcome of a disease and therefore the future for the patient . His prognosis is grim, for example, while hers is good.
See the entire definition of Prognosis

Prostaglandin: One of a number of hormone-like substances that participate in a wide range of body functions such as the contraction and relaxation of smooth muscle, the dilation and constriction of blood vessels, control of blood pressure, and modulation of inflammation. Prostaglandins are derived from a chemical called arachidonic acid.
See the entire definition of Prostaglandin

Pupil: The opening of the iris. The pupil may appear to open (dilate) and close (constrict) but it is really the iris that is the prime mover; the pupil is merely the absence of iris. The pupil determines how much light is let into the eye. Both pupils are usually of equal size. If they are not, that is termed anisocoria (from "a-", not + "iso", equal + "kore", pupil = not equal pupils).
See the entire definition of Pupil

Residual: Something left behind. With residual disease, the disease has not been eradicated.
See the entire definition of Residual

Rule out: A term much used in medicine, meaning to eliminate or exclude something from consideration. The ACB (albumin cobalt binding) test helps rule out a heart attack in the differential diagnosis of severe chest pain.
See the entire definition of Rule out

Sensitivity: 1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.
See the entire definition of Sensitivity

Sign: Any objective evidence of disease. Gross blood in the stool is a sign of disease. It can be recognized by the patient, doctor, nurse, or others. In contrast, a symptom is, by its nature, subjective. Abdominal pain is a symptom. It is something only the patient can know.
See the entire definition of Sign

Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
See the entire definition of Surgery

Therapy: The treatment of disease .
See the entire definition of Therapy

Tonometry: A standard eye test that determines the fluid pressure inside the eye. Increased pressure is a possible sign of glaucoma , a common and potentially very serious eye problem if not detected and treated promptly. It is recommended that adults over age 40 have tonometry for glaucoma every 3 to 5 years by having their eye pressures measured.
See the entire definition of Tonometry

Topical: Pertaining to a particular surface area. A topical agent is applied to a certain area of the skin and is intended to affect only the area to which it is applied. Whether its effects are indeed limited to that area depends upon whether the agent stays where it is put or is absorbed into the blood stream.
See the entire definition of Topical

Ultrasound : High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy . There is no convincing evidence for any danger from ultrasound during pregnancy.
See the entire definition of Ultrasound

Visual field: The entire area that can be seen when the eye is directed forward, including that which is seen with peripheral vision.
See the entire definition of Visual field

Vitrectomy: Removal of the gel (called the vitreous) from within the eyeball. This may be done because it has blood and scar tissue in it that blocks sight. An eye surgeon then replaces the clouded gel with a clear fluid.
See the entire definition of Vitrectomy

Vitreous: A clear, jelly-like substance that fills the middle of the eye. Also called the vitreous humor, "humor" in medicine referring to a fluid (or semifluid) substance.
See the entire definition of Vitreous

Most Popular Topics

Explore 80+ Centers

Search Medical Dictionary

or A-Z List

We subscribe to the HONcode principles. Verify here.

©2008 WebMD, Inc. All rights reserved.
eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information.