Microbiology Practice Exam

What disease is known to be the leading cause of blindness?

1. Cataracts

2. Glaucoma

3. Trachoma

4. Macular degeneration

The correct answer is: Trachoma

Trachoma is recognized as the leading cause of blindness worldwide, primarily affecting individuals in developing regions. This infectious disease is caused by the bacterium Chlamydia trachomatis and is transmitted through personal contact, contaminated water, and flies. The repeated infections can lead to scarring of the inner eyelid and inversion of the eyelashes (trichiasis), which ultimately results in corneal damage and blindness if left untreated. While cataracts, glaucoma, and macular degeneration are significant causes of visual impairment and can lead to blindness, they are not the leading causes globally in terms of infectious disease. Cataracts typically result from aging or environmental factors but are treatable with surgery. Glaucoma, a group of eye conditions that damage the optic nerve, can cause severe vision loss but is generally not as prevalent in low-income countries where trachoma is endemic. Macular degeneration primarily affects older adults and is associated with age rather than infectious processes. Thus, the emphasis on trachoma as the leading cause highlights the intersection of infectious disease control and public health measures aimed at reducing preventable blindness, particularly in vulnerable populations.