3. Trachomatous scarring (TS)
Introduction
The presence of scarring in the tarsal conjunctiva. Once the presence or absence of TF and TI has been determined the tarsal conjunctiva should be examined for the presence of scarring. Scarring on the conjunctiva appears as slender white bands that generally run in a transverse direction.
If scars are easily visible, then the diagnosis of trachomatous scarring should be made. Only scars that lie within the grading area should be considered.
Trachomatous scarring (TS)
Definition
The presence of easily visible scarring in the tarsal conjunctiva.
Scars appear more frequently in older people, however in areas with hyperendemic trachoma it is not unusual to see scarring in children.
It is important not to confuse scarring with pale areas of conjunctiva. The pressure of the finger holding the elevated lid in position can cause an area of conjunctiva to blanch.
In the clinical setting this can be easily confirmed by altering the pressure on the lid to see if colour is restored when blood returns. However, when observing pictures, it must simply be kept in mind.
Figure 11: Mild scars traversing the lid.
Figure 12: Severe scarring with Arlt's line.
In more advanced disease, the thin transverse bands of scar tissue can coalescence to form a thickened band. This is particularly common across the superior part of the lid and is called Arlt’s line. Thick bands of scar tissue can cause alterations in the architecture of the lid and lead to trachomatous trichiasis and blindness.