Definition of Amsler grid

Amsler grid: While conducting an eye examination, the
eye care professional may ask the patient to look at an Amsler grid.
This grid is a pattern that resembles a checkerboard. The patient
covers one eye and stares at a black dot in the center of the grid.
While staring at the dot, the patient may notice that the straight
lines in the pattern appear wavy.



This kind of wavy pattern on viewing the Amsler grid is abnormal.
It can be an important warning sign of what is called wet age-related
macular degeneration. The macula is an area in the retina of the
eye that is responsible for central (straight-ahead) vision. It
deteriorates most often after age 60 resulting in age-related macular
degeneration (AMD). An early sign of the dangerous "wet" type of
AMD is the wavy appearance of the lines on the Amsler grid. The early
diagnosis of wet AMD is critical since laser surgery is urgently
needed to preserve sight.

The Amsler grids shown here are reduced in size; eye care
specialists have full-size grids in their office and for the patient
to use at home.

Definition of AMD

AMD: Age-related macular degeneration (which may also be abbreviated as ARMD).

Definition of Amaurotic familial idiocy

Amaurotic familial idiocy:
An outdated term for Tay-Sachs disease (TSD) which is concisely defined by OMIM (Online Mendelian Inheritance in Man) as "an autosomal recessive, progressive neurodegenerative disorder, which in the classic infantile form, is usually fatal by age 2 or 3 years, results from deficiency of the enzyme hexosaminidase A. " "Autosomal" points to the gene for TSD residing on a nonsex (autosomal) chromosome (namely, chromosome15q23-q24). "Recessive" indicates a person with 2 copies of the gene has TSD whereas someone with 1 copy is a carrier in normal health. TSD worsens, with time, as the central nervous system progressively deteriorates. The "classic" ("textbook") type of TSD has its insidious onset in infancy. The child with TSD usually develops normally for the first few months of life. An exaggerated startle reaction may first be noted. Head control is lost by 6-8 months of age. The infant cannot roll over or sit up. Spasticity and rigidity develop. Excessive drooling and convulsions become evident. Blindness and head enlargement set in by the second year. "Fatal by age 2 or 3 years" today would be modified to "fatal by age 5." After age 2, total constant nursing care is needed. Death is due usually to cachexia (wasting away) or aspiration pneumonia initiated by food going down "the wrong way" into the lungs. TSD is due to deficiency of an enzyme (a protein needed to catalyze a specific chemical reaction within the body). Lack of the enzyme which results in failure to process a lipid (a fat) which accumulates and is deposited in the brain and other tissues, to their detriment. The enzyme is called hexosaminidase-A (hex-A) and the lipid that is deposited is called GM2-ganglioside TSD is a model of a fatal metabolic disease that occurs primarily within a well-defined subpopulation. It is one of several genetic diseases found more often in persons of Jewish origin. (Other Jewish genetic diseases include Gaucher disease, Niemann-Pick disease, Bloom syndrome, and factor XI deficiency). The frequency of TSD is much higher in Ashkenazi Jews (of European origin) than in other groups of Jews. (In the U.S., 95% of Jews are Ashkenazi and are at risk for TSD). TSD occurs more rarely, in non-Jews. Knowledge of the biochemical basis TSD has permitted screening programs for carrier detection and prenatal diagnosis of TSD. There are forms of TSD with somewhat more hex-A and hence later onset, termed juvenile TSD and adult TSH. Alternative names for TSD itself are type 1 GM2-gangliosidosis, B variant GM2-gangliosidosis, hexosaminidase A deficiency, hex-A deficiency. TSD is named for the English physician Waren Tay (1843-1927) and the New York neurologist Bernard (Barney) Sachs (1858-1944). Tay in 1881 studied an infant with progressive neurological impairment and described "symmetrical changes in the yellow spot in each eye", the "cherry-red spots" characteristic of TSD. Sachs saw a child In 1887 and the child's sister in 1898 with the cherry-red spots and "arrested cerebral development" and in 1910 he demonstrated the presence of accumulated lipid in the brain and retina.

Definition of Age-related deafness

Age-related deafness: See: Presbycusis.

Definition of Age by decade

Age by decade: A term designating someone's age by decade. For example, a septuagenarian refers to someone in his or her seventies (age 70 to 79). The prefix in such terms is always from the Latin. For example, the Latin septuageni = seventy.

Denarian: Someone age 10 to 19.
Vicenarian: Someone in his or her twenties.
Tricenarian: Someone in his or her thirties.
Quadragenarian: Someone in his or her forties.
Quinquagenarian: Someone in his or her fifties.
Sexagenarian: Someone in his or her sixties.
Septuagenarian: Someone in his or her seventies.
Octogenarian: Someone in his or her eighties.
Nonagenarian: Someone in his or her nineties.
Centenarian: Someone 100 or more.
Supercentenarian: Someone 110 years old or more (no upper limit).
The terms denarian, vicenarian, tricenarian, and quadragenarian are not in common usage. The term supercentenarian was coined in 1991.