Entropion is the turning-in
of the eyelid, towards from the eyeball - which may lead to eyelashes
rubbing against the eye causing irritation called trichiasis.
The lower-eyelids are more commonly affected that the upper-eyelids because
the tissue that supports the upper-eyelids is wider and more stable than
that supporting the lower-eyelids.
Entropion is is usually uncomfortable, involving itching/irritation,
the sense of "something" feeling like grit being in the eye,
watering of the affected eye.
There are several forms of entropion (classified according
- Involutional entropion - the most common form of
entropion, this is due to the changes in the tissue
of the eyelid(s) associated with the normal ageing process. For example,
the small muscles controlling the affected eyelid may have weakened.
In this case either or both eyes may be affected. This is also known
as senile entropion.
- Cicatricial entropion - related to scarring e.g.
due to accident burns or surgery (recall that cicatrix
is the medical term for a scar). Either one or both eyes may be affected.
- Spastic entropion - of the lower-eyelid may be due
to (possibly temporary) spasm of the orbicularis oculus muscle, e.g.
- Congenital entropion - that is, entropion
present since birth.
This is very rare but when present may be due to hypertrophy, i.e. increased
size (due to enlargement of the cells) of the skin of the affected area
or the orbicularis oculi muscles responsible for opening/closing the
eyes. Either one, or both, eyes may be affected.
Surgery may be recommended. If so, the procedure is usually a small adjustment
turing the eyelid back to its ideal position - at which eyelashes do not
rub against the eyeball.
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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