Day Blindness is also known as Hemeralopia
(medical name) and as Night Sight (not to be confused
with "Night Blindness").
Day Blindness is the term
used to refer to comparatively good vision in poor light
but poor vision in good illumination.
An alternative definition of Day Blindness is "a
visual defect characterised by the inability to see as clearly in bright
light as in dim light".
The meaning of the term Day Blindness is therefore quite
easy to remember from its name, though less so when the medical term "Hemeralopia"
Day Blindness is usually congenital (meaning
"present since birth"). However, it may sometimes be
acquired (meaning occur in a person who did not have the condition
previously), for example if the cones
in the retina
are damaged or destroyed e.g. by disease.
See for comparison Night
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.
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