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How to Test for Trachoma

Trachoma is a disease of the eye that is caused by the infectious microorganism Chlamydia trachomatis. It is transmitted by contact with discharge through fingers, towels or handkerchiefs and by flies. It predominates in areas with water shortages, poor hygiene and crowded living conditions. Chronic exposure or repeated infections cause the eyelid to turn inward, exposing the cornea to the eyelashes. This can cause scarring and permanent visual impairment. It affects about 84 million people worldwide, causing visual impairment in about 10 percent of sufferers.

Things You'll Need

  • Binocular loupes (2.5x magnification or greater)
  • Bright light or light source
  • Grading card (Supplied by the World Health Organization, see Resource)
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Instructions

  1. Physical Examination

    • 1

      Put on the binocular loupes.

    • 2

      Examine the patient in adequate light. The patient should be examined in full daylight, or with the use of a bright lamp or flashlight. The grading system depends on detection of small features and differences in color.

    • 3

      Observe the eyelids and corneas. Trachoma causes inturned eyelashes and corneal opacity.

    • 4

      Evert the upper eyelid. Evert (turn over or turn inside out) the upper eyelid to observe the tarsal conjunctiva. The tarsal conjunctiva is the pink tissue on the inside of the eyelid. The grading card supplied by the World Health Organization shows a dotted border for the exact area to be examined. The normal conjunctiva is pink, smooth, thin and transparent. Deep blood vessels will be seen running vertically through the healthy conjunctiva.

    • 5

      Check for follicles. Follicles are round swellings at least 0.5 mm in diameter--smaller are not significant in this diagnosis. They will appear paler than the surrounding tissue. Follicles indicate trachomatous inflammation, with the medical term "Trachomatous inflammation--follicular" (TF).

    • 6

      Check for intense inflammation. The tarsal conjunctiva will appear red and roughened and thickened. This state is usually accompanied with numerous follicles (see Step 5) that may be partially or completely covered by the thickened conjunctiva. This stage of the disease is graded as "Trachomatous inflammation--follicular and intense" (TF + TI).

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