Night Blindness is also known as Nyctalopia
(medical name).
| Night Blindness is the inability
(or severely reduced ability) to see in low-light levels,
such as at dusk and at night.
Note that those affected can, in the absence of other conditions,
see to a normal extent during typical "daytime" light-levels
. |
Night Blindness is generally due to a disorder of the
rods,
which are the cells in the retina
of the eye
that are most important for vision in dim light (i.e. low-light levels,
such as occur at night).
There are many possible reasons for a disorder of the rods, leading to
Night Blindness.
For example,
- Congenital (since birth) Night Blindness
- Deficiency of Vitamin A
- Malabsorption - if it adversely affects absorption of Vitamin A
- Retinitis
pigmentosa
- Sorsby's fundus dystrophy (a genetic eye inflammatory disorder.)
- Pathological myopia
(myopia ="short-sightedness")
- Peripheral cortical cataract
- Oguchi's disease
See also, for comparison, Day
Blindness (also known as Hemeralopia).
More about Ophthalmology: This section includes short definitions
of many diseases, disorders, and conditions of the eyes and visual system.
For definitions of other terms in this category, choose from the list
to the left (but note that this is not a complete/exhaustive list).
Other related pages include the diagram
of the eye, and definitions
of parts of the eye, a description
of the human retina, and definitions
of parts of the retina, and the section of short definitions
of clinical and surgical procedures re. eyes and human visual system.
For further information see also our section of Books
about Ophthalmology. |
 |
This Section
is about
Diseases
and Disorders of the Eyes and Visual System.
To read about other diseases, disorders, or conditions of the eye and
human visual system, use the links on the left-side of this page.
|
