Trichiasis:
The term trichiasis means the abnormal direction of the eyelashes. The abnormal lashes rub against the corneal surface of the eyeball with resultant irritation, watering and potential damage to the cornea.
Causes:
All causes of entropion (entropion = lid margins turn inward) produce trichiasis, for example, spasm of the muscle of riolan, fibrosis of palpebral conjunctiva, loss of tone and elasticity of lid margins, Steven Johnson's syndrome.
Pure trichiasis occurs in the following conditions
1. Congenital Trichiasis: It is also called Distichiasis. In this disorder, an extra row of cilia is present behind the grey line in the place of ducts of the meibomian glands. Meibomian glands are absent.
2. Acquired Causes:
a) Trachoma, due to fibrosis distorting the follicles.
b) Ulcerative blepharitis: due to fibrosis near the follicles.
Symptoms and signs:
1. Sandy or foreign body sensation
2. Photo-phobia
3. Lacrimation (watering)
Complications:
1. Chronic conjunctivitis
2. Conjunctival ulceration
3. Epithelial plaque
4. Corneal epithelial defects
5. Superficial vascularization
6. Epidermoid change in cornea
4. Secondary bacterial infection.
Treatment:
Pure trichiasis is treated by operation.
1. If the upper lid is involved then it is corrected by "Van-Millengen's operation" which consist of displacing the rubbing lashes by placing a mucus graft in the grey line.
2. If lower lid is involved then it is corrected by "Webster's operation" in which a mucus graft is placed in an incision which is made in sulcus subtrasalis.
3. If rubbing lashes are more than four then they are treated by.
a) Thermal coagulation
b) Diathermy
c) Chemical coagulation (NaOH)
d) Electrolysis.