Symptoms and the 5 Clinical Signs of Trachoma

Trachoma is tracked by health programs using five clinical signs defined by the World Health Organization (WHO) simplified grading system ^[1]. Understanding these signs is vital because the early phases often have very few symptoms, yet they set the foundation for future vision loss ^[2].

Health workers assess these signs by gently everting (turning inside out) the upper eyelid to inspect the conjunctiva, the pink lining on the underside of the lid ^[3].

Important Safety Warning: Do not attempt to force an eyelid open or diagnose these signs yourself at home. Conditions like allergies and other infections can also cause red eyes and bumps. Rely on a trained health worker to perform this exam safely.

The Active Signs: Often Seen in Childhood

The first two clinical signs are known as “active trachoma.” These represent the body’s immediate reaction to the bacteria ^[4]. Patients do not always progress neatly from one to the next; these signs can co-exist.

• TF: Trachomatous Inflammation—Follicular: A health worker will look for at least five follicles—small, pale, white or yellow bumps—on the inside of the upper eyelid ^[5].
  • What you may feel: Often, there are no symptoms at all ^[2]. Some children may have a slightly red or “sticky” eye with a small amount of discharge ^[6].
• TI: Trachomatous Inflammation—Intense: In this presentation, the inflammation is more severe. The lining of the eyelid becomes thick, red, and swollen, often hiding the normal blood vessels underneath ^[1].
  • What you may feel: The eye may feel irritated or painful. This sign is particularly concerning because intense inflammation is a strong predictor of future scarring ^[7].

The Scarring Signs: Late-Stage Damage

As a person grows older, repeated bouts of active infection lead to permanent changes in the eyelid. This “scarring phase” can continue even if the original infection has been treated ^[8].

• TS: Trachomatous Scarring: The follicles from the active phase heal and leave behind white lines or patches of scar tissue on the inside of the eyelid ^[9].
  • What you may feel: You might not feel anything at this stage. However, these scars are irreversible and act like a tightening drawstring, gradually pulling the eyelid inward ^[9][10].
• TT: Trachomatous Trichiasis: This is a critical sign where the scarred eyelid has turned inward, causing the eyelashes to scratch the eyeball ^[11]. Note that while the official WHO program definition focuses on upper eyelid lashes for tracking purposes, any inward-turning eyelash on the upper or lower lid can damage the cornea and requires prompt assessment ^[1].
  • What you may feel: This is often very painful. It feels like having sand or a “foreign body” constantly scratching the eye ^[10]. You may also experience light sensitivity and constant tearing ^[12]. Lashes touching the eye require prompt clinical evaluation.
• CO: Corneal Opacity: The constant scratching from the eyelashes causes the cornea—the clear window of the eye—to develop dense, cloudy, or white patches ^[13].
  • What you may feel: Vision becomes blurry or may be lost entirely ^[11]. A cloudy cornea must be evaluated by a professional, as opacities can also be caused by injuries or other infections ^[10].

Why Professional Screening is Essential

Because the transition from “bumps” (TF) to “scars” (TS) happens slowly over many years, you might not notice the damage until the painful stage of inward-turning lashes begins ^[8]. Regular eye checks by trained health workers are the only way to catch trachoma in its early, silent stages ^[14]. It is also important to remember that clinical signs like TF can sometimes persist for months even after the bacteria have been cleared by antibiotics, which is why health workers may continue to monitor or treat a community even if people feel healthy ^[15].