Trachoma is a contagious bacterial infection that develops in eyes, caused by the bacteria Chlamydia trachomatis, and primarily spreads by contact with an infected person or infected flies.

According to World Health Organization's (WHO) trachoma grading system, trachoma can be divided into 5 types or stages: Trachomatous inflammation, follicular (TF); trachomatous inflammation, intense (TI); trachomatous scarring (TS); trachomatous trichiasis (TT); and corneal opacity (CO).

A bacterium called Chlamydia trachomatis is responsible for developing trachoma, and it can spread by direct contact such as touching infected eye secretions, indirect contact such as touching contaminated items such as blankets, in addition to the ability of certain flies to spread the disease.

Risk factors that increase the risk of having trachoma include poverty, crowded environments, and being female. Trachoma infection triggers an immune response marked by a distinct inflammatory cell infiltrate with the secretion of pro-inflammatory cytokines in the conjunctiva.

Sign and symptoms associated with trachoma include scarring and distortion of the upper eyelid, mild itching and irritation of the eyes, light sensitivity, and eye pain.

Diagnostic steps that used by healthcare professionals to diagnose trachoma include reviewing of patient’s medical history, performing a physical exam, and recommending certain lab tests such as polymerase chain reaction (PCR).

Treatment options of trachoma include administering certain Antibiotic medications such as azithromycin and surgery. However, if not well treated, the disease can lead to various complications such as an inward folding eyelid that dubbed entropion, inwards turning of lashes that dubbed trichiasis, and corneal scarring or cloudiness.

To prevent the disease from occurring, certain preventive measures can be suggested such as washing hands and face, using proper waste management, and controlling flies.

An excellent prognosis has been reported when proper treatment given at early stages of the disease. However, worldwide, about 1.9 million people have developed blindness and visual impairment due to trachoma according to WHO.

Trachoma is a contagious bacterial infection that develops in eyes, caused by the bacteria Chlamydia trachomatis, and primarily spread by contact with an infected person or infected flies. Moreover, trachoma is considered the world's leading infectious cause of blindness, and repeated trachoma infections are known to cause scars inside the eyelids.

The World Health Organization advocates the using of a simplified grading system to classify trachoma:

• Trachomatous inflammation, follicular (TF): To assert the presence of this type, five or more follicles, which are small bumps that contain a type of white blood cell known as lymphocytes, must be visible on the inner surface of the upper eyelid when examined with magnification.
• Trachomatous inflammation, intense (TI): This type results in significant conjunctival scarring and blindness by thickening of the upper tarsal conjunctiva, leading to obscureness of more than half of the normal tarsal vessels.
• Trachomatous scarring (TS): In this type, scarring of the inner eyelid occur due to repeated infections. The scars take the form of white lines when closely examined.
• Trachomatous trichiasis (TT): At this stage or type, fibrosis and corneal opacification occur because of eyelashes touching the globe.
• Corneal opacity (CO): At this stage or type, the cornea becomes inflamed due to an inflammation that mostly seen under the upper lid.

A bacterium called Chlamydia trachomatis is responsible for developing trachoma as well as chlamydia, which is popular sexually transmitted infection.  Trachoma is usually transmitted by:

• Direct contact that includes touching infected nasal secretions or infected eye secretions.
• Indirect contact such as touching contaminated items such as blankets, sheets, towels, or clothing.
• Certain flies can also spread the bacteria.

Several factors can increase the risk of contracting trachoma include:

• Poverty: Trachoma is more common to spread among extremely poor populations in developing countries.
• Crowded environments: The risk of spreading trachoma increases among people living in close contact. For instance, sharing a bedroom with someone who has the disease can increase the risk of contracting the infection.
• Animals in close proximity: The risk of contracting the disease increases with keeping cattle or other animals close to the home.This happens because of the favorable muscid breeding medium found in human and animal feces.
• Flies: People become more susceptible to infection when they live in areas were a large number of flies present.
• Poor sanitation: lack of hygiene such as unclean faces or hands, and poor sanitary conditions can facilitate the spreading of infection.
• Living inland: This due to the fact that coastal populations are able to clean themselves by swimming in the sea.
• Age: The risk of contracting trachoma mostly increases among children ages 4 to 6.
• Gender: Some investigators believe that females are more susceptible to contract trachoma approximately two to six times higher than males.
• Lack of latrines: A higher incidence of the disease presents in communities or areas with not enough working latrines.

Trachoma is an infection of the eye caused by Chlamydia trachomatis, which typically infects columnar epithelial cells.Chlamydia trachomatis is a gram-negative, coccoid bacterium that can stimulate a poorly understood inflammatory response that can cause conjunctival scarring and blinding.

Chlamydia trachomatis spreads passively by flies, aerosol droplets, or by fomites contaminated by secretions. The infection triggers an immune response marked by a distinct inflammatory cell infiltrate with the secretion of pro-inflammatory cytokines in the conjunctiva.

Active infections can lead to follicular inflammation with mucopurulent keratoconjunctivitis. A single episode of infection can be healed; however, repeated infections can result in conjunctival damage that may develop eventually to cause inward turning of the eyelid or entropion, and continual eyelash irritation of the cornea or trichiasis.

Symptoms of trachoma appear 5 to 12 days after the exposure to the bacteria. However, many people with trachoma may show no symptoms at all. Symptoms of trachoma include:

• Scarring and distortion of the upper eyelid due to repeated episodes of reinfection,
• Mild itching and irritation of the eyes and eyelids,
• Swelling of lymph nodes a front of the ears,
• Abnormal growth of corneal blood vessels,
• Mucus or pus discharge from the eyes,
• Turned-in eyelashes,
• Light sensitivity,
• Cornea scarring,
• Swollen eyelids,
• Cloudy cornea,
• Eye pain.

An ophthalmologist can perform the following to help diagnose trachoma:

• Medical history: An ophthalmologist may ask questions regarding previous health issues, in addition to symptoms present.

• Physical examination: An ophthalmologist may perform an eye exam to identify any scar formation inside of the upper eyelid, new blood vessel growth into the cornea, in addition to examine the redness of the white part of the eyes.
• Lab tests: These tests are helpful in identifying the bacteria to draw the accurate diagnosis.  However, trachoma diagnosis is normally made by clinical examination. Lab tests may include :

1. Polymerase chain reaction (PCR) and ligase chain reaction (LCR) which are known to have high sensitivity and specificity.
2. Direct fluorescein-labeled monoclonal antibody (DFA) and enzyme immunoassay (EIA) of conjunctival smears which are relatively new tests.
3. Giemsa cytology (the finding of intracytoplasmic inclusions) which is technically demanding with high specificity but low sensitivity.

Moreover, trachoma can be identified clinically when any of the following are confirmed:

• Presence of five or more follicles >0.5 mm in diameter.
• Presence of conjunctival scarring.
• Presence of limbal follicles or Herbert pits.
• Presence of corneal neovascularization and granulation tissue formation.

The severity of the condition determines best treatment option, but may include:

• Antibiotic medications: The preferable treatment for uncomplicated cases is a single oral dose of an antibiotic called azithromycin.Azithromycin is known to be safe, effective, well-tolerated with few side effects.
• Surgery: A surgery may be recommended by specialists to prevent long-term scarring, that may lead to blindness if not properly managed. In eyelid rotation surgery, a surgeon makes an incision in the scarred lid and rotates the eyelashes away from the cornea.

Repeated trachoma infections can lead to many possible complications, including:

• Entropion, which is an inward folding eyelid.
• Trichiasis , which is inwards turning of lashes.
• Corneal scarring or cloudiness.
• Scarring of the inner eyelid.
• Partial or complete vision loss.

Some preventive measures to limit the spreading of the trachoma infection can include:

• Avoid sharing items such as towels.
• Washing hands and face often.
• Proper waste management.
• Improved access to water.
• Keeping clothes clean.
• Controlling flies.

Moreover, there is a form of trachoma control method called “SAFE”, which has been developed by the World Health Organization. “SAFE” stands for:

• S -surgery for trichiasis.
• A -antibiotics, prescribing azithromycin to fight the infection.
• F -facial cleansing and general hygiene.
• E-environmental improvements that relate to water, sanitation and fly control.

An excellent prognosis has been reported when proper treatment is given at early stages of the disease but repeated infection worsens the prognosis. However, vision may not improve although severe disease may show stability at some point.

The followings are part of the available information regarding the epidemiology of trachoma as mentioned by World Health Organization (WHO):

• Globally, about 1.9 million people have developed blindness and visual impairment due to trachoma. In 2016, 190.2 million people lived in trachoma-endemic areas and were at risk of trachoma blindness.
• In 2016, 85 million people were treated with antibiotics to improve trachoma, and more than 260 000 people received surgical treatment for advanced trachoma.
• Africa remains the most affected continent with 18 million cases of active trachoma (85% of all cases globally), and the highest prevalence of active trachoma exists in Ethiopia and South Sudan.
• Trachoma is accounted for S$ 2.9–5.3 billion annually as an economic cost in terms of lost productivity from blindness and visual impairment. The figure increases to US$ 8 billion when trichiasis is included