Trachoma is a disease of the eyes that causes the inflammation of eyes known as Kerato-conjunctivitis (the eyes become red and painful) that leads to blindness when not treated. Trachoma was initially called Egyptian ophthalmia; it is the leading cause of preventable blindness in the world. Trachoma is caused by an organism called Chlamydia trachomatis. There are different serotypes of Chlamydia trachomatis which include serotypes A, B, Ba and C. Repeated trachoma infection causes chronic eye disease that leads to blindness and this can occur commonly in endemic regions.
Table of Contents
- Trachoma Causes
- Trachoma Epidemiology
- Trachoma Risk Factors
- Trachoma Mode of Transmission
- Trachoma Pathophysiology
- McCallans Trachoma Classification of 1908 (Four stages of Trachoma)
- Trachoma Stages (Classification of Trachoma – WHO Grading System based on Clinical features at presentation)
- Trachoma eye disease pictures and description
- Trachoma Symptoms and Signs
- Trachoma Diagnosis
- Trachoma Treatment
- Trachoma Prevention
- Trachoma Complications
- Chlamydia trachomatis serotype A
- Chlamydia trachomatis serotype B
- Chlamydia trachomatis serotype C
There is an estimated worldwide population of about 150 million people currently infected with Trachoma and about 6 million people worldwide have been blinded by trachoma infection. It is a disease commonly found among the poor and children are more affected than adults (it is common in Children). Trachoma is affects about 500 million people worldwide and is the 3rd major cause of blindness worldwide even though it is preventable and curable. There is higher prevalence in Southern Asia, the Middle East and some parts of Africa such as the northern parts. This infection has been eradicated in Europe and Taiwan.
Trachoma Risk Factors
- Insanitary habits
- Lack of clean water
- Abundant population of flies
Trachoma Mode of Transmission
Trachoma is spread by flies picking Chlamydia trachomatis from an infected persons eye to another person. Chlamydia trachomatis can also be transmitted sexually but the serotype of chlamydia trachomatis that causes sexually transmitted infections (STDs) is different from the type that causes Trachoma.
Trachoma infection occurs bilateral (both eyes are affected at the same time) and begins in the conjunctiva, with marked follicular inflammation and subsequent scarring. Trachoma causes the formation of granulations or follicles in the inflammatory stages which is then followed by diffuse infiltration and papillary hypertrophy of the conjunctiva with extension of blood vessels to the surface of the cornea.
The inflammation of the eyes in Trachoma may disappear spontaneously or may progress towards conjunctival cicatrization (scarring of the conjunctiva) which then leads to inward deviation of the eyelid margin called Entropion. Scarring of the conjunctiva may distort the growth of the eyelashes and cause inward growing of the eyelashes towards the cornea a condition referred to as trichiasis. This in-growing of the eyelashes causes irritation of the cornea and subsequent ulceration that leads to cornea scarring or opacification and permanent blindness sets in after about 10 to 15 years.
In mild cases of trachoma, the inflammation heals without causing permanent loss of vision the final result of Trachoma infection depends on the degree of damage to the cornea some may have mild infection and healing occur with no effect on vision while others may have severe infection with total blindness occurring.
McCallans Trachoma Classification of 1908 (Four stages of Trachoma)
- Trachoma Stage I: the incipient trachoma or stage of infiltration is characterized by hyperemia of palpebral conjunctiva and immature follicles.
- Trachoma Stage II this is an established trachoma or stage of florid infiltration and it is characterized by appearance of mature follicles, papillae and progressive corneal pannus.
- Trachoma Stage III in this, Cicatrising trachoma or stage of scarring includes obvious scarring of palpebral conjunctiva.
- Trachoma Stage IV this is healed trachoma or stage of sequelae
Trachoma Stages (Classification of Trachoma – WHO Grading System based on Clinical features at presentation)
- TF = Trachomatous inflammation (Follicles): this stage has five or more follicles measuring at least 0.5mm in size and found on the ‘flat’ surface of the upper tarsal conjunctiva.
- TI = Trachomatous inflammation – (Intense): in this stage, inflammatory thickening of the upper tarsal conjunctiva occurs with more than half of the normal deep tarsal vessels obscured
- TS = Trachomatous Scarring: this occurs when scarring of the tarsal conjunctiva (fibrosis) develops
- TT = Trachomatous trichiasis: when at least one eyelash rubbing on the eyeball or evidence of eyelash removal
- CO = Corneal Opacity: the stage where at least part of the pupil is blurred or obscured.
Trachoma eye disease pictures and description
Trachomatous Inflammation Follicular (TF)
In this Trachoma stage, there are about 5 or more follicles, each of which must be at least 0.5mm in diameter, on the flat surface of the upper tarsal conjunctiva.
The picture shows a number of follicles in early and active stage of trachoma. They are accumulations of tiny lymphoid cells. The follicles are rounded in shape and looks pale compared to the remaining conjunctival surface; the follicles are also slightly raised. While staging trachoma, the corners of the everted eyelid and the lower edge of the everted conjunctiva are not considered.
Trachomatous Inflammation Intense (TI) Stage of Trachoma
Presence of marked inflammatory thickening of the upper tarsal conjunctiva with obscurity of more than half of the deep conjunctival blood vessels. This stage of trachoma is highly infectious.
Infection at this stage is very active and the tarsal conjunctiva becomes thickened and inflamed. This stage shows diffuse inflammatory infiltration with edema and enlarged vascular papillae. There should be more than half of the deep conjunctival vessels being covered with inflamed conjunctiva and the blood vessels are becoming invisible for this stage to be called the Intense Trachomatous Trachoma.
Trachomatous Scarring (TS)
There is scarring of the tarsal conjunctiva in this stage. The picture shows presence of white and yellow lines forming a basketwork of fibrous scarring in the tarsal conjunctiva with some Scars disappearing as white lines or appearing as bands or sheets with different shapes and angles with some looking like the edge of a feather. There is scarring most times in adults but may rarely be present in older children.
Trachomatous Trichiasis (TT)
This Trachoma stage is commoner in females than males and mostly starts in adolescence and becoming prevalent with increasing age. There is evidence of one or more eyelashes rubbing on the eyeball. Even when one eyelash or a number of eyelashes have recently been removed it is still termed as Trachomatous trichiasis. Self-removal of eyelashes by a patient due to irritation is termed as Epilation.
Corneal Opacity (CO)
This can occur about 20 years after the initial infection. Corneal scarring occurs when the scarring is central and sufficiently dense to obscure part of the margin of the pupil. Once scarring has occurred, there cant be improvement in vision with medical treatment.
Trachoma Symptoms and Signs
- Redness of both eyes (conjunctivitis)
- Scarring of the upper eyelids leading entropion (inward positioning of the eyelids)
- Scarring of the cornea as a result of inward bending of the eyelashes (trichiasis) that touch the cornea and irritate it
- Blindness as a result of cornea opacity
Diagnosis of Trachoma is clinical according to the presence of two of the following clinical features:
- Presence of healed Follicles on the upper tarsal conjunctiva or on the limbal area called Herbert’s pits. The Herbert’s pits are the oval or circular pitted scars, left after healing of the follicles in the limbal area
- Presence of Epithelial or sub-epithelial keratitis that is most marked in the upper third of the cornea
- Presence of Pannus (abnormal layer of granulation tissue) on the cornea (that is most marked superiorly)
- Characteristic scars of the lids and cornea and their sequelae such as entropion and trichiasis these two sequelae of scarring of the lids further aggravate the process of irritation and opacification of the cornea and result in total blindness.
Trachoma infection may also occur as an acute ophthalmic infection in neonates or Ophthalmia neonatorum (newborn conjunctivitis) this type is a one of the venereal diseases and occurs as secondary eye infection in a newborn child, found to have an eye infection as a result of transmission occurring in the mothers birth canal. Neonates therefore should have immediate application of tetracycline 1% eye ointment in each eye at birth, as a prophylactic measure against this type of Chlamydia trachomatis infection.
- The treatment of choice in Trachoma is the use of Systemic therapy with a single dose of 20mg/kg of Azithromycin
- Use of topical antibiotics such as tetracyclines and erythromycin is very effective in treatment of Trachoma if and only if the patient can comply with treatment. The topical antibiotics are applied 2 times in a day for 5 consecutive days this is done every month for a period of 6 months
- If there is complication such as Entropion and trichiasis, then surgical correction is needed to prevent opacification of the cornea or for eyelid reconstruction
- Prevention of the disease to avoid reinfection
Treatment guideline for Trachoma is done using the WHO safe strategy for Trachoma (WHO S.A.F.E approach): Surgery, Antibiotics, Facial cleanliness and Environmental improvement. Do not give these systemic antibiotics to women during pregnancy. If you need to treat women of child-bearing age then erythromycin 500 mg twice a day is a safe alternative. Doxycycline and tetracycline should not be given to children under the age of 7 years.
- Mass treatment using of children using Topical Tetracyclines in communities where Trachoma prevalence is 20% or more
- Provision of good clean water
- Improved sanitation to prevent flies
Prevention of Trachoma is reflected in the World Health Organization – WHO SAFE approach
to trachoma which includes: Surgery, Antibiotics, Facial cleanliness, and Environmental improvement. WHO aims to eradicate Trachoma by year 2020.
- Blindness: this may occur many years after infection with Chlamydia trachomatis
- Entropion: in-folding of the eyelids
- Trichiasis: in-folding of eyelashes
Trachoma is not a very infectious disease as the complications occur due to secondary bacterial infections that aggravate the disease and facilitate transmission which is by contact with infected material.