Trachoma
in Pictures
Clinical grading.
Trachoma
is a clinical diagnosis, made by examining the conjunctivae of the eye in good
light using a 2.5x magnification lens.
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Fig 1. The upper eye-lid has been turned over to examine the
conjunctiva over the stiffer part of the upper lid, as dotted in. The
normal conjunctiva shown here is pink, smooth and transparent. Large,
deep-lying blood vessels normally run vertically over the whole area of
the conjunctiva. From the World Health
Organisation Prevention of blindness web site.
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Fig 2. Trachomatous inflammation TF. There
must be 5 or more follicles on the upper conjunctiva. Follicles must be at least
0.5 mm in diameter and are round, whitish, paler than the surrounding
conjunctiva.
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The
initial response to eye infection with trachoma agents is
conjunctivitis involving the palpebral and bulbar conjunctivae. The conjunctiva
 is inflamed, slightly swollen and congested, with papillary
hypertrophy
prominent in the palpebral conjunctiva. This is followed by lymphoid follicle
formation, most commonly on the palpebral conjunctiva (Fig 2). However follicles
may also be found on the bulbar conjunctiva. Trachomatous inflammation grade TF
involves the presence of at least five lymphoid follicles on the upper
conjunctiva. Pannus
may
also be present.
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| Fig 3. Shallow pits at the limbal margin of the
bulbar conjunctiva, caused by the rupture of lymphoid follicles leaving
small scarred depressions termed Herbert's pits. These are considered,
together with lymphoid follicles or vascular pannus, as one of the
characteristic diagnostic signs of trachoma. |
Fig 4. Intense trachomatous inflammation, TI.
The tarsal conjunctiva appears red, rough and thickened, obscuring more
than half of the normal, deep, tarsal vessels. There are numerous
follicles which are partially covered by the thickened conjunctiva. Figure
kindly provided by the World Health Organisation. |
Conjunctival
follicles, after rupture, may leave shallow pits, termed Herbert's pits (Fig
3). [Herbert was an English ophthalmic surgeon, 1865 -
1942]. In some areas of the world secondary bacterial infection with Moraxella
or other species is common giving rise to discharge of pus from the eyes [Wood
& Dawson, 1967].
Cicatricial
trachoma.
Severe
initial infection, but more commonly repeated re-infection in an endemic area,
leads to the development of conjunctival scarring (Fig 5).
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| Fig 5. Grade TS. Scarring and fibrosis of the
tarsal conjunctiva in response to severe or chronic trachoma. This is
sometimes called cicatricial trachoma. The scars, glistening and
fibrous in appearance, are easily visible as white lines, bands or even
sheets. Scarring and, particularly, diffuse fibrosis may obscure the deep
conjunctival blood vessels. Scarring is important because it gives rise to
the blinding sequelae of trachoma. |
Fig 6. Grade TS. An example of more sheet-like
fibrosis of the conjunctiva as a result of trachoma. The conjunctival
blood vessels are almost entirely obscured. Severe trachomatous scarring
such as this is usually seen in older adults, and in women more commonly
than men.
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Severe scarring of the tarsal
conjunctiva distorts the eyelid, a condition called entropion (Fig 7).
This re-directs the eyelashes inwards so that they lash the orb of the eye, (trichiasis)
leading to corneal damage and visual loss (Fig 8).
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Fig 7. Grade TT. Trichiasis is defined
as occurring when at least one eye-lash rubs on the eye-ball as a result
of entropion of the lid. The inturned eye-lashes are irritating,
leading to attempts to remove them. Evidence of recent attempts to remove
inturned eye lashes in a trachoma endemic community should also be graded
TT.
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Fig 8. Grade TT & CO. The eyelashes
have abraded the cornea, damaging it, leading to corneal opacity
and undoubted visual loss. The tragedy is that this loss could have been
prevented at the right time by surgical correction of the eye lid
deformity, a procedure which can be performed in rural villages, takes
about 15 minutes and costs roughly US$ 20.
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NEXT: Prevalence and
distribution of trachoma
[MEW] March 2002
Web resource
WHO Prevention of
Blindness Program web
site
References
Thylefors, B., Dawson, C. R.,
Jones, B. R., West, S. K. & Taylor, H. R. (1987). A simple system for
the assessment of trachoma and its complications. Bulletin of
the World Health Organisation 65, 477 - 483. 
West, S. K. & Taylor, H. R. (1990). Reliability
of photographs for grading trachoma in field studies. British
Journal of Ophthalmology 74, 12 - 13.
Wood, T. R. & Dawson, C.
R. (1967). Bacteriologic studies of a trachomatous population. American
Journal of Ophthalmology 63, Suppl:1298-301.
NEXT: Prevalence and
distribution of trachoma
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