MacCallan’s Classification of Trachoma

Stage 1 (T I)

Stage 2 (T II)

Stage 3 (T III)

Stage 4 (T IV)

Appearance

Immature follicles

Small

Grayish

Not raised above the surface

Not expressible

T IIa mature follicles

Large

Pinkish

Raised above the surface

Expressible T IIb papillae

Soft

Pinkish red

Finger-like

Narrow topped

1. Patches of fibrosis affecting upper palpebral conjunctiva & a dense white line at sulcus subtarsalis (Arlet’s line)

2. PTDs & PTCs

Complete healing, no follicles nor papillae (as T III)

Pathology

Cellular infiltration surrounding the invading

organism leading to formation of aggregations of

lymphocytes and surrounded by giant multinucleated cells

(Leber’s cells)

1. Follicles enlarge and undergo central necrosis

2. Infiltration increases around a core of blood vessels covered by epithelium papillae

1. Degeneration occurs in conjunctival crypts in between papillae (PTDs)

2. Calcification may occur in these degenerated areas (PTCs)

Patient becomes not infective

(no inclusion bodies in conjunctival scrapings

stained by Giemsa stain)