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, and watering of the affected eye.
There are several forms of entropion (classified according to cause).
- 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. following surgery.
- 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 and closing of 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
- A diagram of the eye
- Definitions and descriptions of the parts of the eye
- A concise description of the human retina
- Definitions of parts of the retina
- Clinical and surgical procedures re. eyes and human visual system
For further information see also our pages of books about ophthalmology.