Clinical History:

A 21-year-old woman from Bangladesh has had decreasing vision in her left eye "for years." Physical examination reveals left corneal and conjunctival scarring. Her eyelashes are partly turned in, scratching the surface of the eye. A conjunctival scraping is made for diagnosis.

Microscopic Pathology:

There is an intracytoplasmic elementary body of Chlamydia trachomatis in the cell to the left of the arrow.

Questions:

1. What is the diagnosis?

This is trachoma, a chronic, progressive infection of the eye with Chlamydia trachomatis infection, which produces scarring of the conjunctiva and cornea leading to partial or complete blindness.

2. What are risk factors?

Trachoma is the most common cause for preventable blindness worldwide. Persons living in overcrowded rural communities with limited access to water and health care are at greatest risk. Trachoma is passed easily from person to person in a cycle of infection and re-infection. Mothers of young children are particularly susceptible, and the majority of persons affected are women.

3. What is the treatment?

Trachoma typically begins in childhood and progresses for years with repeated infections. Infection causes irritation and scarring on the conjunctiva of the inner eyelid, known as trichiasis. Trichiasis causes the eyelashes to turn inward and repeatedly scratch the surface of the cornea, resulting in permanent scarring and eventual permanent blindness. Blindness usually occurs in middle age. The inturned eyelashes can be plucked out, but they will regrow. A surgical procedure can reverse the inturned eyelashes. However, prevention consists of frequent face washing. The early stages of infection can be treated with topical tetracycline or azithromycin.

4. Name another cause for preventable blindness.

Vitamin A deficiency, which primarily affects children.