What is Trachoma? A persistent inflammation of the cornea and conjunctiva brought on by specific Chlamydia trachomatis serotypes. Pannus, or vascular invasion of the cornea, and subsequent blindness are its defining features. One major cause of blindness is trachoma. It is more prevalent in arid, filthy, and crowded places.

How Trachoma is Transmitted?

Direct contact with an infected person’s ocular secretions can spread trachoma. This can happen directly through discharge-contaminated fingers or indirectly through flies and fomites. During the early stages of the disease, Chlamydia trachomatis is prevalent. The most contagious phases are the initial ones. Children and others living in endemic areas are at significant risk of contracting the virus at a young age. Blindness before the age of ten is frequent, although the disease often advances extremely slowly. Vitamin A deficiency and secondary bacterial infections worsen the condition and increase the risk of scarring, which can result in blindness.

Clinical Features of Trachoma

The incubation period of trachoma is 5 to 12 days, after which the affected individual experiences symptoms of conjunctivitis, or irritation similar to ‘pink eye’. The conjunctival inflammation is called ‘active trachoma’ and usually is seen in children, especially preschool children. The active trachoma is characterized by white lumps in the undersurface of the upper eye lid (conjunctival follicles or lymphoid germinal centres) and by non-specific inflammation and thickening often associated with papillae. Follicles may also appear at the junction of the cornea and the sclera (limbal follicles).

Stages of Trachoma Infection

1. Stage I (Trachomatous Inflammation – Follicular – TF) marks the onset of trachoma, characterized by red, watery eyes resembling typical conjunctivitis. After a month or longer, small pinkish-grey nodules, known as follicles, develop within the upper eyelids. The sclera exhibits mild inflammation. Pus is minimal unless a bacterial superinfection occurs.The pre-auricular lymph nodes begin to swell.
2. Stage II (Trachomatous Inflammation – Intense – TI) is characterized by significant diffuse inflammatory infiltration, edema, and vascular papillary hypertrophy. The upper edge of the cornea appears grayish due to the presence of numerous tiny blood vessels (pannus). The combination of follicles and pannus is nearly diagnostic of trachoma.
3. Stage III (Trachomatous Scarring – TS) occurs after several years, during which the follicles begin to fade, leaving behind white scars on the conjunctiva. The small vessels in the cornea regress. A diffuse haze persists on the cornea. Some vision may be preserved unless severe damage, such as corneal rupture from scarring, has taken place. The scars are located on the inner surface of the conjunctiva.
4. Stage IV (Trachomatous Trichiasis – TT) involves the retraction of scar tissue, causing the eyelid to thicken and turn inward, a condition known as entropion. These scars result in thickened and narrowed eyelids, which may restrict their full opening or cause the eyelashes to turn inward, leading to corneal abrasion with each blink, a condition referred to as trichiasis.

Conclusion

Trachoma is a significant cause of blindness, primarily affecting individuals in arid and overcrowded regions, and is transmitted through direct contact with infected ocular secretions. The disease progresses through distinct stages, leading to severe complications such as scarring and trichiasis, which can ultimately result in vision loss.