Trachoma or Egyptian blindness was once the most leading cause of preventable blindness in the world. With the advent of antibiotic era and other medical procedures, it has decreased in the past few years but it still continues to be a major threat in the developing countries or wherever there are poor hygienic practices and unsafe water supply.
Many people in fact, still regard it as the major cause of preventable blindness in the world. It is caused by Chlamydia trachomatis. Before going into the medical details of the disease, there is an interesting history that is associated with trachoma and is given below in nutshell.
What is trachoma?
It is a highly contagious disease which starts as a nonspecific conjunctivitis in its acute form and with the chronic form takes over to lid scarring mostly in turning of the lid margin leading to in turning of the eyelash and thus rubbing on the cornea causing its most dreaded complication which is blindness. It is caused by Chlamydial trachomatis (A, B, Ba, C, D to K serotypes).
Trachoma has a very long and an interesting history since it dates back to around 8000 B.C. When first evidence of the blinding disease was found in Australia in Australian skulls that had abnormal structure due to an invasion of some microorganism into the bone but not out of it. Trachoma was the most fitting eye diseases that the scientists said could have caused that picture in those skulls.
Written therapies to cure trachoma were also found in China dating back to 2600 B.C.
It was also present in Ancient Greece and Rome. Few of the plays by Aristophanes also contains some references to Trachoma like in Plutus (one of the plays) where Plutus who is the God of Riches is blinded by Zeus. This is said to be an allusion to the blinding disease that had set its tight claws on Greece.
It was Dioscorides who used the term “trachoma” for the first time in 60 A.D. in his work Materia Medica.
The Hippocratic Corpus also had sections about trachoma dating back to 5th century B.C.
Trachoma is also called Egyptian Ophthalmia because when Napoleon had begun his conquest in Egypt in 1798, the disease infected three thousand of Napoleon’s troops in two and a half months and even blinded many of them. Therefore, it also began to be called Military or Egyptian ophthalmia from then.
Thus these troops spread Trachoma from an endemic Egypt to sporadic Europe and made the problem grave in Europe, the infection now spreading in even European civilians.
Infection also spread to the U.S. through immigrants despite of strict medical screening and checkups.
Halberstaedter and Prowazek discovered trachoma inclusion bodies in 1907.
Mccallen created classification of trachoma into four stages around 1913.
The successful treatment of trachoma occurred for the first time in 1937 with the use of sulphonamides.
While use of Penicillin in treatment of trachoma occurred for the first time in 1940. Use of Streptomycin started in 1943.
Chinese first isolated Chlamydia in a chick embryo in 1954 and so it was called a virus and then it was called a bacteria because it had DNA and RNA both and was susceptible to antibiotics.
In 1996, WHO called to use Azithromycin for the treatment of the disease.
In 1999, there was establishment of Vision 2020, in which one of the goals was to eliminate this blinding disease ‘trachoma’ by the year 2020.
Did you know?
Here are some interesting facts related to trachoma just for the sake of interesting read:
1. For the the treatment of trichiasis (a complication of trachoma in which an eyelash or few eyelashes turn inwards rub on the cornea and lead to blindness), the Ebers papyrus suggested a treatment way back in 1550 B.C. The treatment was to remove the in turned eyelash and apply a mixture of myrrh’s (a lizard) blood, and bat’s blood until healed or a mixture of lizard dung, oxblood ass’ blood, pig blood, hound blood, Goat blood, stibium and malachite.
2. St. Paul, Cicero and Galileo had trachoma.
3. Many governments considered trachoma as a serious threat and thus firm decisions were taken in context to prevent its spread in their own territory through immigrant legislation.
4. Some immigrants used adrenaline topically to mask their trachoma signs and fool the officers. Some immigrants also rubbed sugar cubes on their eyelashes 6 weeks before the immigration to temporarily hide their symptoms.
5. Trachoma also has its mention in Mario Puzo’s ‘The Godfather’, Mark Twain’s ‘Innocents Abroad’, and Bill Bryson’s ‘In A Sunburned Country’.
6. In England, this was one of the procedures to treat trachoma back in the eighteenth century. It was blood letting in which various cuts were made near the eye and blood was let to flow from these cuts until the person fainted.
7. There was something known as the soldiers’ plot to fake ophthalmia to avoid serving in the military.
It is endemic in many parts of the world like the Middle East, Central Asia, India, Pakistan, Bangladesh, Eastern Asia that is China and Japan, The Pacific Islands, North and central Africa, Central and South America. It is estimated to affect around 21.4 million people around the globe with five-sixth of them suffering with active trachoma and one-sixth of them having its complication trichiasis.
Presently it is the second most common cause of preventable blindness after cataracts. The most vulnerable groups are that of women and children with preschool children being most affected 60-90 percent in hyper endemic areas. There is an increased risk of development of blindness and complications in women than in men.
Risk factors or Causes
1. Unhygienic practices like not washing hands often, rubbing eyes with dirty or bare hands frequently and overcrowding.
2. Sharing same towels, clothes.
3. Fomites like door handles (already being touched with infected hands and fingers).
4. Flies or other vectors which are attracted to eye discharge.
5. Sexual transmission from infected genitals to hands and then from hands to eye.
6. Basically transmission is bye eye to eye or genitals to eye.
5. Coming in contact with eyes of the infected person.
Pure trachoma is mostly symptomless. Symptoms are mainly due to secondary bacterial infection and may be minimal like foreign body sensation in the eyes, mild lacrimation, itching etc. It may also give a picture similar to acute bacterial conjunctivitis when there is severe secondary bacterial infection like mucopurulent discharge, red eye, etc.
The complications or the sequelae may take even 20 years to emerge. In chronic stages there may be intense pain, lacrimation and photophobia when the cornea is involved due to trichiasis.
- Conjunctival signs: Signs in the conjunctiva.
- Corneal signs: Signs in the cornea.
Conjunctival signs include
a. Congestion or Redness: There is redness of the upper tarsal (palpebral) conjunctiva or say fold of conjunctiva covering the back of the eyelid and can be seen when the eyelid everted. This is mainly due to the response of the body against the invading microorganism in the form of inflammation in this which includes dilatation of the blood vessels of the conjunctiva.
b. Papillary enlargement: There is redness in the tarsal conjunctiva, the reason being the above described that is dilatation of the blood vessels as a protective mechanism in response to the microorganism. But this time the inflammation or the dilatation is extensive and causes jelly like appearance of the tarsal conjunctiva that is more reddish and velvety appearance.
c. Follicles: Follicles have mostly boiled sagograin like look and are mainly seen on the upper tarsal conjunctiva. They are formed due to collection of the protective cells of the body that is the lymphocytes in response to the microorganism as a part of the inflammation. The centre of the follicle have the protective cells called the mononuclear histiocytes(cells with single nucleus) and leber cells( which are large cells with many nuclei inside a single cells also called giant cells). In the periphery, the follicle is mainly made up of collection of lymphocytes.
If follicles are less than 5mm in diameter than they can be due to follicular conjunctivitis but a follicle with diameter greater than 5 mm is only seen in trachoma. A follicle seen on the bulbar conjunctiva is pathognomonic or a sure shot sign of trachoma.
d. There can be Scarring of the conjunctiva.
e. Concretions: They are formed due to collection or mounding up of dead epithelium of the conjunctiva due to invasion and destruction by the Chlamydia. They look like white hard deposits which are usually pinpoint in size.
Corneal signs include
a. Keratitis is the inflammation of the cornea which is usually seen in the upper part and mainly in the superficial layers of the cornea.
b. Herbert follicles: follicles which are present at the junction of conjunctiva and the cornea that is limbus that is at the periphery or margin of the cornea. They are also a part of inflammation and due to collection of lymphocytes.
c. Pannus: It means something invading the cornea or something infiltrating the cornea. It is usually associated with entering of blood vessels in the normally avascular cornea which is called vascularization. This infiltration is mainly of the lymphoid cells and it is most commonly seen in the upper part but gradually and slowly it can involve whole of the cornea. The margin of the cornea starts looking cloudy and hazy and unclear due to this infiltration and vessels can be clearly appreciated springing up from outside into the cornea.
Pannus is of two types
Progressive pannus: In this the infiltration is ahead of vascularization and the vessels are mainly parallel, vertical and face downwards ahead of which lines a strip of infiltration.
Regressive pannus: In this filtration lags behind the vascularization that is vessels extend a distance beyond the haze of the infiltration.
Such classification is necessary to decide upon the course of the treatment.
The vessels are usually superficial that is they lie between the bowmanns’s membrane and the epithelium and at that stage the treatment of pannus does not lead to corneal opacity but if the vascularization becomes deep (destroyed the bowmann’s membrane), a permanent corneal opacity may result despite of the treatment.
d. Corneal ulcer: It usually takes place at the edge of the pannus which is advancing already and are generally shallow but may become deep as the time passes by.
e. Herbert pits: When the herbert follicles explained above heal, they leave scars behind which are called herbert pits. These pits are usually brown in colour and oval in shape.
f. Corneal opacity: A permanent haze or cloudiness can occur in cornea either due to corneal ulceration or due to deep pannus which may affect the vision of the person especially if the opacity is in the region of the pupil by blocking the light entering the pupil.
Complications or sequelae of trachoma:
1. Sequelae in the lids: The most common one being trichiasis, which causes rubbing on the cornea and blindness. Trichiasis is rubbing of the eyelash against the eyeball. It usually takes places because of in turning of the lid margin due to scarring of the palpebral conjunctiva. This in turning of the lid margin is called Entropion, which is another complication. There can be thickening of the lid margin which is called tylosis. There can be drooping eyelid also.
Due to dense infiltration there is a specific type of drooping of the upper eyelid giving the patient a sleepy appearance. It is also called ‘trachomatous ptosis.’
Classification of trachoma:
WHO classification is the most accepted one and that is the FISTO classification:
There was also MacCallan’s classification:
Clinical diagnosis is made by history, specific signs and FISTO classification described above.
For routine diagnostic use, A simplified form of micro-immunofluorescence test is done using pooled antigens. It does not use the antigens involving individual trachoma inclusion conjunctivitis.
Direct examination of the conjunctival smear with the help of Direct Monoclonal fluorescent antibody microscopy is also a rapid and an inexpensive method.
Conjunctival cytology- Conjunctival smears are taken and stained with Giemsa stain. If the smear shows neutrophils with presence of plasma cells and Leber cells, it is suggestive of trachoma.
Detection of inclusion bodies can also be suggestive of trachoma and is done by staining conjunctival smears with Giemsa,iodine stain or immunofluorescent staining.
ELISA can be done for chlamydial antigens.
Isolation of Chlamydia can be done by yolk sac inoculation method. MacCoy cell culture can also be used and it requires three days.
Treatment is divided into two phases:
- Treatment of the active phase.
- Treatment of the sequelae.
1. Treatment of the active phase:
Azithromycin remains the first drug of choice presently. It is given as 1g stat (when diagnosed). Tetracycline and Erythromycin have also been tried with success systemically but Tetracycline is not given to children below 8 years, pregnant women or nursing mothers. The schedule is as follows:
- Oral tetracycline or erythromycin 250 -500mg four times a day for 3-6 weeks.
- Oral Doxycycline 100mg twice a day for 3-6 weeks
- Oral Clarithromycin 250-500mg twice a day for 3-6 weeks.
Topical treatment with erythromycin and tetracycline is more effective than topical sulfonamides. The treatment is repeated in trachoma control programmes and is called the intermittent treatment that is after the continuous treatment of trachoma for active trachoma for 6 weeks, the intermittent treatment is started by giving the medication for 5 consecutive days of a month for 12 months.
Continuous treatment consists of:
- Tetracycline 1% eye ointment or erythrocycline 1% eye ointment 4 times a day for 6 weeks or
- Sulfacetamide 20% eye drops three times a day along with 1% tetracycline ointment at bedtime for 6 weeks.
- Combined systemic and local therapy is given when the infection is severe.
2. Treatment of trachoma sequelae:
- Trichiasis: It needs epilation or cryolysis or electrolysis.
- Entropion is also corrected surgically, it will be dealt as a separate topic too.
- Dry eye is treated by artificial tears.
- Pannus requires no treatment as such and usually resolves with regression of the inflammatory activity of the conjunctiva.
1. Hygienic living:
- Proper handwashing.
- Do not rub eyes frequently.
- Environmental hygiene, no flies etc.
- Use separate towels, cloths.
- Use clean towels and cloths.
- Use separate handkerchiefs, surma rods or kajal sticks.
- Proper face washing at regular intervals.
- Sexual hygiene: No Sexually Transmitted Diseases should be there, if exist, take proper treatment.
2. Any sort of conjunctivitis should be treated properly and at the earliest to prevent transmission.
3. The intermittent therapy described above should be followed in national trachoma control programmes. It is also called WHO Blanket antibiotic therapy.
4. Various steps were taken by WHO. They started GET 2020 (Global Elimination of Trachoma by 2020) in 1997, under which primary health care activities were initiated and they followed a SAFE strategy.
S: Surgery for the lid.
A: Antibiotic to treat the community pool of infection.
F: Facial cleanliness
E: Environmental changes.
Vision 2020 also included trachoma in its list and runs on the lines of GET 2020 in context of trachoma.
1. History of Trachoma by Katherine Schlosser.
2. A.K Khurana, MD “Ophthalmology” (New Age International Publisher, Inc 2012) Chapter: Optics and refraction p59-66.
3. Parsons, Disease of the Eye (Elsevier, 21 Edition), p174-176.