Trachoma

Overview

Trachoma is an infectious eye disease caused by the bacterium Chlamydia trachomatis. It is highly contagious and spreads through contact with the eyes, eyelids, nose, or throat secretions of infected individuals, as well as through handling contaminated items like handkerchiefs. Initial symptoms often include mild itching and irritation of the eyes and eyelids, progressing to swollen eyelids and pus drainage from the eyes if left untreated.

The disease is the leading preventable cause of blindness globally, primarily affecting impoverished regions in Africa where 85% of those with active trachoma live. In these areas, the rate of infection among children under five can exceed 60%, exacerbated by poor hygiene, limited access to clean water, and overcrowded living conditions.

The World Health Organization (WHO) categorizes the development of trachoma into five stages:

• Inflammation — follicular: This initial infection is characterized by the presence of five or more follicles—small bumps filled with lymphocytes, a type of white blood cell—visible under magnification on the inner surface of the upper eyelid (conjunctiva).
• Inflammation — intense: At this highly infectious stage, the eye becomes irritated with a noticeable thickening or swelling of the upper eyelid.
• Eyelid scarring: Chronic infections lead to the scarring of the inner eyelid. These scars typically present as white lines under magnification. This can cause the eyelid to distort and potentially turn inward (entropion).
• In-turned eyelashes (trichiasis): Continued deformation from scarring causes the eyelashes to turn inward, scratching the transparent outer surface of the eye (cornea).
• Corneal clouding (opacity): Ongoing inflammation, especially under the upper eyelid, coupled with damage from the in-turned lashes, results in the clouding of the cornea.

Early intervention and treatment are crucial in managing trachoma and preventing its severe complications, which can lead to irreversible blindness. Efforts to improve hygiene, water access, and sanitation are essential in combating this public health issue, particularly in vulnerable communities.

Symptoms

Early stages of trachoma: In the initial phases of trachoma, individuals may experience:

• Red and irritated eyes
• Swollen eyelids
• Blurred vision
• Watery discharge from the eyes
• Nasal discharge

Advanced trachoma (Trachomatous Trichiasis): Advanced trachoma typically develops after multiple infections and inflammation episodes. Key features include:

• Scar tissue formation inside the eyelids, causing them to tighten.
• Eyelashes that turn inward due to the tightened eyelids
• Severe eye pain from eyelashes scraping against the cornea.
• Increased sensitivity to light
• Impaired vision, which can lead to blindness if untreated.

This progressive condition primarily affects the cornea, the clear, curved front of the eye, leading to its opacity and reduced light transmission.

Causes

Trachoma, caused by the bacterium Chlamydia trachomatis—which is also responsible for the sexually transmitted infection chlamydia—involves certain subtypes that affect the eyes. The disease spreads through contact with the discharges from the eyes or nose of an infected person. Various transmission routes include insects, hands, clothes, and towels. In developing countries, eye-seeking flies also play a significant role in transmitting this infectious disease.

Risk factors

The following factors that increase your risk of developing trachoma:

• Age: The disease primarily affects youngsters between the ages of 4 and 6 in places where it is common.
• Crowded place: Infection transmission is more likely amongst closely spaced residents.
• Flies: Infection risk may be higher in residents of places where fly populations are difficult to manage.
• Poor sanitation: The disease can spread due to unhygienic environments, insufficient water supply, and poor personal hygiene, including dirty hands and faces.
• Sex: Women are more likely to get the disease in some places more than men. Women may be more likely to interact with children than men, who serve as the main source of infection.