Ingrown eyelashes (trichiasis) is when the lashes turn inwards and rub against the front of the eye causing irritation. It may be due to conditions of the lid or the lining of the lid (conjunctiva) eg. blepharitis – inflammation of the edge of the lids.
It can also be caused by injuries to the lid such as burns or by previous surgery.
Trichiasis should not be confused with entropion, which is when the lid itself is turned inwards rather than just the lashes.
Different treatment is needed for this. It is possible to have both entropion and trichiasis at the same time and treatment for both these conditions may be needed.