Blind Spot: From 2 Different Sources
The small, oval-shaped area on the retina of the eye where the optic nerve leaves the eyeball.
The area is not sensitive to light because it has no light receptors (nerve endings responsive to light).
The blind spot can also be used to describe the part of the visual field in which objects cannot be detected.
the small area of the *retina of the eye where the nerve fibres from the light-sensitive cells (see cone; rod) lead into the optic nerve. There are no rods or cones in this area and hence it does not register light. Anatomical name: punctum caecum.
A disorder in which abnormal FAECES occur as a result of a redundant loop in the small INTESTINE. The loop obstructs the normal ?ow of the contents of the bowel, causing stagnation. The syndrome is characterised by light-yellow, smelly, fatty, bulky faeces. The patient suffers from tiredness, malaise and loss of weight. Previous abdominal surgery is sometimes the cause, but the condition can be inherited. Blockage of intestinal contents upsets the bowel’s normal bacterial balance and hinders the normal absorption of nutrients. Treatment is either with antibiotics or, if that fails, surgery.... blind loop syndrome
A scienti?c study in which di?erent patients receive a di?erent drug, the same drug at a different dose, or a placebo – with neither the investigators assessing the outcome nor the subjects being treated knowing which of these the latter are receiving. The aim is to remove any hint of bias due to the investigators’ or patients’ preferences or preconceptions. The results are analysed after all the data have been collected and the code has been broken. Trials should have a separate supervising committee, the members of which know the code but do not take part in the study. Their job is to check the results at intervals so they can stop the trial if one arm of treatment is clearly better than another. Otherwise, it would be unethical to continue. (See INTERVENTION STUDY.)... double blind trial
A fever of the typhus group (see TYPHUS FEVER). It received its name from the fact that it was ?rst reported in the Rocky Mountain States of the United States; these are still the most heavily infected areas, but the fever is now found in all parts of the US. The causative organism is Rickettsia rickettsi, which is transmitted to humans by tics.... rocky mountain spotted fever
A misnomer applied to the brown MACULES often seen on the backs of the hands of those chronically exposed to sunlight (see LENTIGO). They have no connection with any liver disorder.... liver spots
Irregularly shaped areas of bluish-black pigmentation found occasionally on the buttocks, lower back or upper arms in newborn infants of African, Chinese and Japanese parentage, and sometimes in the babies of black-haired Europeans. They measure from one to several centimetres in diameter, and usually disappear in a few months. They are commonly mistaken for bruises.... mongolian blue spots
See MENINGITIS; EPIDEMIC; TYPHUS FEVER.... spotted fever
Tiny, grey-white spots that appear in the mouth during the incubation period of measles.... koplik’s spots
De Morgan’s spots are a type of small HAEMANGIOMA occuring in the skin of middle-aged people. No more than 3 mm in diameter, they are rarely widespread and are not malignant.... de morgan’s spots
A tick-borne disease found on Flinder’s Island, north of Tasmania. Zoonotic and caused by Rickettsia honei.... flinder’s island spotted fever
A vague term applied to small in?amed and congested areas which appear especially upon the skin of the face, neck and chest or other parts of the body in warm weather.... heat spots
Bluish-white spots appearing on the mucous membrane of the mouth in cases of MEASLES about the third day, and forming the ?rst part of the rash in this disease.... koplik’s spots
A tick-borne spotted fever endemic to mainland Australia. Caused by Rickettsia australis.... queensland spotted fever
See “blinding”.... single-blind trial
Also called FLOATERS, these can arise from a variety of causes including in?ammation and bleeding in the eye, or preceding a retina detachment. They may also occur for a variety of totally harmless reasons. (See EYE, DISORDERS OF.)... spots before the eyes
See “blinding”.... triple-blind trial
Harmless red or purple raised spots in the skin, consisting of a cluster of minute blood vessels. About 2 mm across, the spots usually affect middle-aged or older people. With increasing age, the spots become more numerous but do not increase in size. They may bleed if injured. Treatment is unnecessary.... de morgan’s spots
A blue-black pigmented spot found on the lower back and buttocks at birth. The spots are a type of naevus and are caused by a concentration of melanocytes (pigmentproducing cells). Mongolian blue spots are commonly found in black or Asian children, and they usually disappear by the age of 3–4 years.... mongolian blue spot
A general term for a small lump, mark, or inflamed area on the skin.... spot
See breakthrough bleeding.... spotting
cheesy foamy greyish spots that form on the surface of dry patches of conjunctiva at the sides of the eyes. They consist of fragments of keratinized epithelium. A common cause is vitamin A deficiency. [P. A. Bitot (1822–88), French physician]... bitot’s spots
(in Britain) an incomplete list of persons who are technically blind or partially sighted due to reduced visual acuity, or who have severely restricted fields of vision (see blindness). Registration is voluntary, but it is a precondition for the receipt of some financial benefits. The list is maintained by local authorities (England and Wales), regional or island councils (in Scotland), or the Health and Social Care Board (Northern Ireland).... blind and partially sighted register
see intervention study.... blind trial
greyish-brown spots seen in the iris of the eye. They can be found in normal individuals but are usually associated with *Down’s syndrome. [T. Brushfield (1858–1937), British physician]... brushfield spots
see angioma. [C. G. de Morgan (1811–76), British physician]... campbell de morgan spots
soft fluffy spots in the retina resulting from accumulations of *axoplasm in the nerve-fibre layer of the retina. These may indicate diseases causing hypoxia (oxygen deficiency) in the nerve-fibre layer (e.g. diabetes, hypertension, connective-tissue disease, or AIDS).... cotton-wool spots
(DSI) the production of static images using an *image intensifier, usually during a fluoroscopic examination. The images can be stored digitally (see digitization) and either transferred to photographic film or viewed on a TV monitor.... digital spot imaging
visible sebaceous glands present in most individuals. They are 1–3-mm painless papules that may be noticed on the scrotum, shaft of the penis, labia, and inner surface and border of the lips. They become more visible from puberty onwards and are easier to see when the skin is stretched. Completely harmless, they are not sexually transmitted or infectious and do not require any treatment. [J. A. Fordyce (1858–1925), US dermatologist]... fordyce spots
pigmented lesions in the macular area of the retina that are seen in severely myopic (short-sighted) individuals. They are breaks in *Bruch’s membrane allowing choroidal *neovascularization and can result in reduced vision. [E. Fuchs]... fuchs’ spots
a pale area surrounded by haemorrhage sometimes seen in the retina, with the aid of an *ophthalmoscope, in those who have bacterial endocarditis, septicaemia, or leukaemia. [M. Roth (1839–1915), Swiss physician]... roth spot
see macula.... yellow spot
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